* [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support
@ 2026-07-02 17:15 Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
` (7 more replies)
0 siblings, 8 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Alexey Charkov, Alice Guo, Andrew Goodbody,
Anshul Dalal, Bo-Chen Chen, Brian Sune, David Lechner,
Dinesh Maniyam, Fabio Estevam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jaehoon Chung,
Jerome Forissier, Julien Masson, Julien Stephan, Kory Maincent,
Kuan-Wei Chiu, Lucien.Jheng, Macpaul Lin, Marek Vasut,
Marek Vasut, Martin Schwan, Mateusz Furdyna, Mattijs Korpershoek,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
NXP i.MX U-Boot Team, Neil Armstrong, Nobuhiro Iwamatsu, Peng Fan,
Peter Robinson, Philip Molloy, Pieter Van Trappen, Quentin Schulz,
Rasmus Villemoes, Raymond Mao, Simon Glass, Stefan Roese,
Stefano Babic, Svyatoslav Ryhel, Tom Rini
This series adds U-Boot's PMBus 1.x support as a small boot-time
layer (not a hwmon clone):
- a decoder + transport library and the pmbus CLI command
- a shared UCLASS_REGULATOR adapter plus a catch-all driver for
compliant chips, add the MPS MPQ8785 per-chip driver
- a generic PMBus die-temperature UCLASS_THERMAL bridge
- migration of the shared NXP VID rail-trim code to this framework
- a sandbox PMBus chip emulator and "ut dm pmbus" unit tests that
exercise most subcommand of the CLI.
The goal is to identify PMBus regulators at boot, print telemetry and
decode chip alerts before the kernel takes over - no polling, no
sysfs, no fan loops. Linux owns the runtime side.
Vincent Jardin (7):
pmbus: add PMBus 1.x framework, CLI, and binding
power: regulator: add generic PMBus UCLASS_REGULATOR adapter
power: regulator: add MPS MPQ8785 PMBus regulator driver
board: nxp: vid: introduce PMBus framework support
thermal: pmbus: add PMBus die-temp driver
test: dm: pmbus: add a sandbox PMBus chip emulator
test: dm: pmbus: test pmbus command and framework
MAINTAINERS | 19 +
arch/Kconfig.nxp | 4 +
arch/sandbox/dts/test.dts | 10 +
board/nxp/common/vid.c | 104 ++-
board/nxp/common/vid.h | 15 +-
cmd/Kconfig | 14 +
cmd/Makefile | 1 +
cmd/pmbus.c | 816 ++++++++++++++++
configs/sandbox_defconfig | 6 +
doc/develop/index.rst | 1 +
doc/develop/pmbus.rst | 636 +++++++++++++
.../regulator/lltc,ltc3882.yaml | 91 ++
.../regulator/mps,mpq8785.yaml | 105 +++
doc/device-tree-bindings/regulator/pmbus.yaml | 65 ++
.../regulator/renesas,isl68233.yaml | 105 +++
drivers/power/regulator/Kconfig | 43 +
drivers/power/regulator/Makefile | 4 +
drivers/power/regulator/mpq8785.c | 494 ++++++++++
drivers/power/regulator/pmbus_generic.c | 90 ++
drivers/power/regulator/pmbus_helper.c | 315 +++++++
drivers/power/regulator/pmbus_helper.h | 90 ++
drivers/power/regulator/sandbox_pmbus.c | 160 ++++
drivers/thermal/Kconfig | 8 +
drivers/thermal/Makefile | 1 +
drivers/thermal/pmbus_thermal.c | 33 +
include/pmbus.h | 666 +++++++++++++
lib/Kconfig | 16 +
lib/Makefile | 1 +
lib/pmbus.c | 876 ++++++++++++++++++
test/dm/Makefile | 1 +
test/dm/pmbus.c | 247 +++++
31 files changed, 4982 insertions(+), 55 deletions(-)
create mode 100644 cmd/pmbus.c
create mode 100644 doc/develop/pmbus.rst
create mode 100644 doc/device-tree-bindings/regulator/lltc,ltc3882.yaml
create mode 100644 doc/device-tree-bindings/regulator/mps,mpq8785.yaml
create mode 100644 doc/device-tree-bindings/regulator/pmbus.yaml
create mode 100644 doc/device-tree-bindings/regulator/renesas,isl68233.yaml
create mode 100644 drivers/power/regulator/mpq8785.c
create mode 100644 drivers/power/regulator/pmbus_generic.c
create mode 100644 drivers/power/regulator/pmbus_helper.c
create mode 100644 drivers/power/regulator/pmbus_helper.h
create mode 100644 drivers/power/regulator/sandbox_pmbus.c
create mode 100644 drivers/thermal/pmbus_thermal.c
create mode 100644 include/pmbus.h
create mode 100644 lib/pmbus.c
create mode 100644 test/dm/pmbus.c
--
2.43.0
base-commit: f605dcee103c897b6f1a8873549a36949bd4e2a1
branch: for-upstream/pmbus-v4
^ permalink raw reply [flat|nested] 24+ messages in thread
* [PATCH v1 1/7] pmbus: add PMBus 1.x framework, CLI, and binding
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
` (6 subsequent siblings)
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Alexey Charkov, Andrew Goodbody, Brian Sune,
David Lechner, Dinesh Maniyam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jerome Forissier,
Julien Stephan, Kory Maincent, Kuan-Wei Chiu, Marek Vasut,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
Neil Armstrong, Peng Fan, Peter Robinson, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
Add U-Boot's PMBus 1.x layer: the decoder/transport library, the
pmbus CLI command and a generic DT binding.
The subsequent commits provide the UCLASS_REGULATOR adapter and per-chip
drivers.
U-Boot's PMBus support is not a hwmon clone of Linux's
drivers/hwmon/pmbus/. Linux owns the runtime side (polling, sysfs,
alert IRQs, fan loops). U-Boot owns the boot-time side in order to,
- identify the PMBus regulators a board carries: MFR_ID/
MFR_MODEL/MFR_REVISION + sanity checks.
- print telemetry (VIN/VOUT/IIN/IOUT/POUT/TEMP) so an
operator can confirm rail voltages and faults before the kernel
- decode any chip alerts (STATUS_VOUT/STATUS_IOUT/STATUS_INPUT/
STATUS_TEMPERATURE/STATUS_CML) so a boot log shows why the
previous boot failed or the board had been power cycled because
of an outage (typically over temperature or under current).
Out of scope by design: no periodic polling, no sysfs, no fan-speed
control loop, no PMBUS_VIRT_* sensor virtualisation, no caching.
If a use case needs any of those, the answer should be "wait until
Linux comes up". It shall remain a thin layer.
The constants and structural shape (command codes, status bit names,
sensor-class enum, format enum, struct pmbus_driver_info) are
mirrored from Linux drivers/hwmon/pmbus/pmbus.h verbatim. The
decoders/encoders are reimplemented from the PMBus 1.3
specification because the surrounding hwmon context (struct
pmbus_data, sysfs caching, hwmon publication) does not apply.
The main benefits:
- One framework + CLI for any board carrying PMBus regulators:
no per-board PMBus implementation required anymore.
- Boards call pmbus_print_telemetry() / pmbus_print_status_word()
directly from boot init for a snapshot, sharing all decode +
format-dispatch with the CLI.
- Linux-compatible constants and DT binding so porting an existing
drivers/hwmon/pmbus/ chip is mechanical.
- Boot-time AVS/VID rail trim reuses the same decoders and
encoders as the CLI and the regulator path: no duplicate math.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 9 +
cmd/Kconfig | 14 +
cmd/Makefile | 1 +
cmd/pmbus.c | 816 +++++++++++++++++
doc/develop/index.rst | 1 +
doc/develop/pmbus.rst | 636 +++++++++++++
doc/device-tree-bindings/regulator/pmbus.yaml | 65 ++
include/pmbus.h | 629 +++++++++++++
lib/Kconfig | 16 +
lib/Makefile | 1 +
lib/pmbus.c | 859 ++++++++++++++++++
11 files changed, 3047 insertions(+)
create mode 100644 cmd/pmbus.c
create mode 100644 doc/develop/pmbus.rst
create mode 100644 doc/device-tree-bindings/regulator/pmbus.yaml
create mode 100644 include/pmbus.h
create mode 100644 lib/pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 571af196465..01553aee45a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1580,6 +1580,15 @@ S: Maintained
F: cmd/pci_mps.c
F: test/cmd/pci_mps.c
+PMBUS
+M: Vincent Jardin <vjardin@free.fr>
+S: Maintained
+F: cmd/pmbus.c
+F: doc/develop/pmbus.rst
+F: doc/device-tree-bindings/regulator/pmbus.yaml
+F: include/pmbus.h
+F: lib/pmbus.c
+
POWER
M: Jaehoon Chung <jh80.chung@samsung.com>
M: Peng Fan <peng.fan@nxp.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index c71c6824a19..63f783ac0b9 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2715,6 +2715,20 @@ config CMD_PMIC
- pmic write address - write byte to register at address
The only one change for this command is 'dev' subcommand.
+config CMD_PMBUS
+ bool "pmbus device interrogation and control command"
+ depends on PMBUS
+ help
+ Enable the pmbus U-Boot CLI command. Provides identification,
+ decoded telemetry, STATUS_* decoding, raw register read/write,
+ CLEAR_FAULTS, and VOUT_COMMAND set/get against any PMBus 1.x
+ compliant device selectable via 'pmbus dev <bus>:<addr>'.
+
+ Per chip drivers and board files publish vendor extensions in
+ the 'pmbus <vendor> ...' namespace.
+
+ See doc/develop/pmbus.rst for the full usage reference.
+
config CMD_REGULATOR
bool "Enable Driver Model REGULATOR command"
depends on DM_REGULATOR
diff --git a/cmd/Makefile b/cmd/Makefile
index bbbdfcc4ded..ce772e5555b 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -228,6 +228,7 @@ obj-$(CONFIG_CMD_AXI) += axi.o
obj-$(CONFIG_CMD_PVBLOCK) += pvblock.o
# Power
+obj-$(CONFIG_CMD_PMBUS) += pmbus.o
obj-$(CONFIG_CMD_PMIC) += pmic.o
obj-$(CONFIG_CMD_REGULATOR) += regulator.o
diff --git a/cmd/pmbus.c b/cmd/pmbus.c
new file mode 100644
index 00000000000..5ddaf3665fc
--- /dev/null
+++ b/cmd/pmbus.c
@@ -0,0 +1,816 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * pmbus U-Boot CLI command.
+ *
+ * Generic command surface over the PMBus 1.x framework defined in
+ * <pmbus.h> + lib/pmbus.c.
+ *
+ * See doc/develop/pmbus.rst for the full usage reference.
+ */
+
+#include <command.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/ctype.h>
+#include <power/regulator.h>
+
+static int parse_bus_addr(const char *s, int *bus_seq, u8 *addr)
+{
+ char busbuf[8];
+ const char *colon;
+ unsigned long b, a;
+ size_t buslen;
+
+ colon = strchr(s, ':');
+ if (!colon)
+ return -EINVAL;
+ buslen = colon - s;
+ if (buslen == 0 || buslen >= sizeof(busbuf))
+ return -EINVAL;
+ memcpy(busbuf, s, buslen);
+ busbuf[buslen] = '\0';
+ if (strict_strtoul(busbuf, 0, &b))
+ return -EINVAL;
+ if (strict_strtoul(colon + 1, 0, &a) || a > 0x7f)
+ return -EINVAL;
+ *bus_seq = (int)b;
+ *addr = (u8)a;
+ return 0;
+}
+
+static const struct {
+ const char *name;
+ u8 reg;
+} pmbus_reg_syms[] = {
+ { "PAGE", PMBUS_PAGE },
+ { "OPERATION", PMBUS_OPERATION },
+ { "ON_OFF_CONFIG", PMBUS_ON_OFF_CONFIG },
+ { "CLEAR_FAULTS", PMBUS_CLEAR_FAULTS },
+ { "WRITE_PROTECT", PMBUS_WRITE_PROTECT },
+ { "CAPABILITY", PMBUS_CAPABILITY },
+ { "VOUT_MODE", PMBUS_VOUT_MODE },
+ { "VOUT_COMMAND", PMBUS_VOUT_COMMAND },
+ { "VOUT_TRIM", PMBUS_VOUT_TRIM },
+ { "VOUT_MAX", PMBUS_VOUT_MAX },
+ { "VOUT_SCALE_LOOP", PMBUS_VOUT_SCALE_LOOP },
+ { "STATUS_BYTE", PMBUS_STATUS_BYTE },
+ { "STATUS_WORD", PMBUS_STATUS_WORD },
+ { "STATUS_VOUT", PMBUS_STATUS_VOUT },
+ { "STATUS_IOUT", PMBUS_STATUS_IOUT },
+ { "STATUS_INPUT", PMBUS_STATUS_INPUT },
+ { "STATUS_TEMP", PMBUS_STATUS_TEMPERATURE },
+ { "STATUS_CML", PMBUS_STATUS_CML },
+ { "READ_VIN", PMBUS_READ_VIN },
+ { "READ_IIN", PMBUS_READ_IIN },
+ { "READ_VOUT", PMBUS_READ_VOUT },
+ { "READ_IOUT", PMBUS_READ_IOUT },
+ { "READ_TEMP1", PMBUS_READ_TEMPERATURE_1 },
+ { "READ_TEMP2", PMBUS_READ_TEMPERATURE_2 },
+ { "READ_TEMP3", PMBUS_READ_TEMPERATURE_3 },
+ { "READ_DUTY", PMBUS_READ_DUTY_CYCLE },
+ { "READ_FREQ", PMBUS_READ_FREQUENCY },
+ { "READ_POUT", PMBUS_READ_POUT },
+ { "READ_PIN", PMBUS_READ_PIN },
+ { "REVISION", PMBUS_REVISION },
+ { "MFR_ID", PMBUS_MFR_ID },
+ { "MFR_MODEL", PMBUS_MFR_MODEL },
+ { "MFR_REVISION", PMBUS_MFR_REVISION },
+};
+
+static int parse_reg(const char *s, u8 *reg)
+{
+ unsigned long v;
+ unsigned int i;
+
+ if (isdigit((unsigned char)s[0])) {
+ if (strict_strtoul(s, 0, &v) || v > 0xff)
+ return -EINVAL;
+ *reg = (u8)v;
+ return 0;
+ }
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++) {
+ if (!strcasecmp(s, pmbus_reg_syms[i].name)) {
+ *reg = pmbus_reg_syms[i].reg;
+ return 0;
+ }
+ }
+ return -EINVAL;
+}
+
+static const char *pmbus_reg_name(u8 reg)
+{
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++)
+ if (pmbus_reg_syms[i].reg == reg)
+ return pmbus_reg_syms[i].name;
+ return "?";
+}
+
+static int require_active(struct udevice **chip,
+ const struct pmbus_active_dev **act)
+{
+ *act = pmbus_active();
+ if (!*act) {
+ printf("pmbus: no active device. Use 'pmbus dev <bus>:<addr>' first.\n");
+ return CMD_RET_FAILURE;
+ }
+ if (pmbus_active_get_i2c(chip)) {
+ printf("pmbus: cannot reach i2c%d:0x%02x\n",
+ (*act)->bus_seq, (*act)->addr);
+ return CMD_RET_FAILURE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static void print_micro(s64 micro, const char *unit)
+{
+ s64 abs_milli;
+
+ abs_milli = (micro < 0 ? -micro : micro) / 1000LL;
+ printf("%lld.%03lld%s",
+ (long long)(micro / 1000000LL),
+ (long long)(abs_milli % 1000LL), unit);
+}
+
+static void print_active(const struct pmbus_active_dev *act)
+{
+ printf("pmbus: active i2c%d:0x%02x", act->bus_seq, act->addr);
+ if (act->name[0])
+ printf(" rail=\"%s\"", act->name);
+ printf(" MFR_ID=\"%s\" MODEL=\"%s\" vendor=%s%s\n",
+ act->mfr_id[0] ? act->mfr_id : "?",
+ act->mfr_model[0] ? act->mfr_model : "?",
+ act->vendor[0] ? act->vendor : "(generic)",
+ act->info ? "" : " [no driver_info]");
+}
+
+static int do_dev(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ int bus_seq, ret;
+ u8 addr;
+
+ if (argc < 2) {
+ act = pmbus_active();
+ if (!act) {
+ printf("pmbus: no active device\n");
+ return CMD_RET_SUCCESS;
+ }
+ print_active(act);
+ return CMD_RET_SUCCESS;
+ }
+
+ if (parse_bus_addr(argv[1], &bus_seq, &addr) < 0) {
+ ret = pmbus_resolve_by_name(argv[1], &bus_seq, &addr);
+ if (ret) {
+ printf("pmbus: '%s' is neither <bus>:<addr> nor a known regulator-name (%d)\n",
+ argv[1], ret);
+ return CMD_RET_FAILURE;
+ }
+ }
+ ret = pmbus_set_active(bus_seq, addr);
+ if (ret) {
+ printf("pmbus: cannot select i2c%d:0x%02x (%d)\n",
+ bus_seq, addr, ret);
+ return CMD_RET_FAILURE;
+ }
+ act = pmbus_active();
+ if (act)
+ print_active(act);
+ return CMD_RET_SUCCESS;
+}
+
+static int do_list(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ struct udevice *dev;
+ struct uclass *uc;
+ int ret, n = 0;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR)) {
+ printf("pmbus: CONFIG_DM_REGULATOR not enabled in this build. Use 'pmbus dev <bus>:<addr>'.\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ ret = uclass_get(UCLASS_REGULATOR, &uc);
+ if (ret) {
+ printf("pmbus: UCLASS_REGULATOR not available\n");
+ return CMD_RET_SUCCESS;
+ }
+ uclass_foreach_dev(dev, uc) {
+ struct dm_regulator_uclass_plat *up = dev_get_uclass_plat(dev);
+ struct udevice *parent = dev_get_parent(dev);
+ const char *rname = (up && up->name) ? up->name : "";
+ const char *drv = (dev->driver && dev->driver->name)
+ ? dev->driver->name : "?";
+ int bus_seq = -1;
+ int addr = -1;
+
+ if (parent && device_get_uclass_id(parent) == UCLASS_I2C) {
+ bus_seq = dev_seq(parent);
+ addr = dev_read_addr(dev);
+ }
+
+ if (n == 0)
+ printf("UCLASS_REGULATOR devices (no PMBus filter):\n");
+ if (bus_seq >= 0 && addr >= 0) {
+ printf(" i2c%d:0x%02x rail=\"%s\" node=%s driver=%s\n",
+ bus_seq, addr, rname, dev->name, drv);
+ } else {
+ printf(" (non-I2C) rail=\"%s\" node=%s driver=%s\n",
+ rname, dev->name, drv);
+ }
+ n++;
+ }
+ if (!n)
+ printf("pmbus: no UCLASS_REGULATOR devices bound. Use 'pmbus dev <bus>:<addr>' to select a chip directly.\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_info(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ static const char * const cls_names[PSC_NUM_CLASSES] = {
+ "VOLTAGE_IN", "VOLTAGE_OUT", "CURRENT_IN", "CURRENT_OUT",
+ "POWER", "TEMPERATURE",
+ };
+ static const char * const fmt_names[] = {
+ "LINEAR", "IEEE754", "DIRECT", "VID",
+ };
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc, c, rrev;
+ u8 rev = 0;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ rrev = pmbus_read_byte(chip, PMBUS_REVISION, &rev);
+
+ printf("pmbus device i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ if (act->name[0])
+ printf(" regulator-name: \"%s\"\n", act->name);
+ printf(" MFR_ID : \"%s\"\n", act->mfr_id[0] ? act->mfr_id : "?");
+ printf(" MFR_MODEL : \"%s\"\n", act->mfr_model[0] ? act->mfr_model : "?");
+
+ /*
+ * MFR_REVISION may encodes the revision as a non printable byte
+ * (BCD nibbles, packed major / minor, etc.). Show both the
+ * printable form and the raw bytes the chip returned.
+ */
+ {
+ u8 raw[PMBUS_MFR_STRING_MAX];
+ int len, i;
+
+ if (dm_i2c_read(chip, PMBUS_MFR_REVISION, raw, 1) ||
+ raw[0] < 1 || raw[0] > sizeof(raw) - 1 ||
+ dm_i2c_read(chip, PMBUS_MFR_REVISION, raw, raw[0] + 1)) {
+ printf(" MFR_REVISION : \"%s\"\n",
+ act->mfr_revision[0] ? act->mfr_revision : "?");
+ } else {
+ len = raw[0];
+ printf(" MFR_REVISION : \"%s\" raw=0x",
+ act->mfr_revision[0] ? act->mfr_revision : "?");
+ for (i = 1; i <= len; i++)
+ printf("%02x", raw[i]);
+ printf("\n");
+ }
+ }
+
+ if (rrev)
+ printf(" PMBUS_REVISION: <read failed (%d)>\n", rrev);
+ else
+ printf(" PMBUS_REVISION: 0x%02x (%s)\n", rev,
+ rev == PMBUS_REV_13 ? "PMBus 1.3" :
+ rev == PMBUS_REV_12 ? "PMBus 1.2" :
+ rev == PMBUS_REV_11 ? "PMBus 1.1" :
+ rev == PMBUS_REV_10 ? "PMBus 1.0" : "unknown");
+ printf(" vendor : %s\n", act->vendor[0] ? act->vendor : "(none)");
+
+ if (!act->info) {
+ printf(" driver_info : not registered (decoders fall back to LINEAR16 / LINEAR11)\n");
+ return CMD_RET_SUCCESS;
+ }
+ printf(" driver_info : pages=%d\n", act->info->pages);
+ for (c = 0; c < PSC_NUM_CLASSES; c++) {
+ printf(" [%-12s] format=%s",
+ cls_names[c], fmt_names[act->info->format[c]]);
+ if (act->info->format[c] == pmbus_fmt_direct)
+ printf(", m=%d, b=%d, R=%d",
+ act->info->m[c], act->info->b[c], act->info->R[c]);
+ printf("\n");
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_telemetry(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ printf("pmbus telemetry @ i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ pmbus_print_telemetry(chip);
+ return CMD_RET_SUCCESS;
+}
+
+static int do_status(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ u16 word = 0;
+ u8 b;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ if (pmbus_read_word(chip, PMBUS_STATUS_WORD, &word)) {
+ printf("pmbus: STATUS_WORD read failed\n");
+ return CMD_RET_FAILURE;
+ }
+
+ const struct pmbus_status_override *ovr =
+ act->info ? act->info->status_overrides : NULL;
+
+ printf("pmbus status @ i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ printf(" STATUS_WORD (79h) = 0x%04x [", word);
+ pmbus_print_status_bits(PMBUS_STATUS_WORD, word,
+ pmbus_status_word_bits, ovr);
+ printf("]\n");
+
+ if (pmbus_read_byte(chip, PMBUS_STATUS_VOUT, &b) == 0) {
+ printf(" STATUS_VOUT (7Ah) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_VOUT, b,
+ pmbus_status_vout_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_IOUT, &b) == 0) {
+ printf(" STATUS_IOUT (7Bh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_IOUT, b,
+ pmbus_status_iout_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_INPUT, &b) == 0) {
+ printf(" STATUS_INPUT (7Ch) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_INPUT, b,
+ pmbus_status_input_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_TEMPERATURE, &b) == 0) {
+ printf(" STATUS_TEMP (7Dh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_TEMPERATURE, b,
+ pmbus_status_temp_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_CML, &b) == 0) {
+ printf(" STATUS_CML (7Eh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_CML, b,
+ pmbus_status_cml_bits, ovr);
+ printf("]\n");
+ }
+
+ return CMD_RET_SUCCESS;
+}
+
+static int do_dump(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ unsigned int i;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ printf("pmbus dump @ i2c%d:0x%02x (registers known to <pmbus.h>)\n",
+ act->bus_seq, act->addr);
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++) {
+ u8 reg = pmbus_reg_syms[i].reg;
+ u8 b = 0;
+ u16 w = 0;
+
+ switch (reg) {
+ case PMBUS_PAGE:
+ case PMBUS_OPERATION:
+ case PMBUS_ON_OFF_CONFIG:
+ case PMBUS_WRITE_PROTECT:
+ case PMBUS_CAPABILITY:
+ case PMBUS_VOUT_MODE:
+ case PMBUS_STATUS_BYTE:
+ case PMBUS_STATUS_VOUT:
+ case PMBUS_STATUS_IOUT:
+ case PMBUS_STATUS_INPUT:
+ case PMBUS_STATUS_TEMPERATURE:
+ case PMBUS_STATUS_CML:
+ case PMBUS_REVISION:
+ if (pmbus_read_byte(chip, reg, &b) == 0)
+ printf(" %02xh %-15s b=0x%02x\n",
+ reg, pmbus_reg_syms[i].name, b);
+ break;
+ case PMBUS_MFR_ID:
+ case PMBUS_MFR_MODEL:
+ case PMBUS_MFR_REVISION: {
+ char s[PMBUS_MFR_STRING_MAX];
+
+ if (pmbus_read_string(chip, reg, s, sizeof(s),
+ act->info ? false : false) >= 0)
+ printf(" %02xh %-15s s=\"%s\"\n",
+ reg, pmbus_reg_syms[i].name, s);
+ break;
+ }
+ default:
+ if (pmbus_read_word(chip, reg, &w) == 0)
+ printf(" %02xh %-15s w=0x%04x\n",
+ reg, pmbus_reg_syms[i].name, w);
+ break;
+ }
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_read(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ const char *fmt = "b";
+ u8 reg, b;
+ u16 w;
+ char s[PMBUS_MFR_STRING_MAX];
+ int rc, ret;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ if (parse_reg(argv[1], ®) < 0) {
+ printf("pmbus: invalid register '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ if (argc >= 3)
+ fmt = argv[2];
+
+ if (!strcmp(fmt, "b")) {
+ ret = pmbus_read_byte(chip, reg, &b);
+ if (ret) {
+ printf("pmbus: read byte 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s b=0x%02x\n", reg, pmbus_reg_name(reg), b);
+ } else if (!strcmp(fmt, "w")) {
+ ret = pmbus_read_word(chip, reg, &w);
+ if (ret) {
+ printf("pmbus: read word 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s w=0x%04x\n", reg, pmbus_reg_name(reg), w);
+ } else if (!strcmp(fmt, "s")) {
+ ret = pmbus_read_string(chip, reg, s, sizeof(s), false);
+ if (ret < 0) {
+ printf("pmbus: read string 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s s=\"%s\"\n", reg, pmbus_reg_name(reg), s);
+ } else {
+ printf("pmbus: unknown format '%s' (expected b, w, or s)\n", fmt);
+ return CMD_RET_USAGE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_write(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ const char *fmt = "b";
+ unsigned long val;
+ u8 reg, b;
+ u8 buf[2];
+ int rc, ret;
+
+ if (argc < 3)
+ return CMD_RET_USAGE;
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ if (parse_reg(argv[1], ®) < 0) {
+ printf("pmbus: invalid register '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ if (strict_strtoul(argv[2], 0, &val)) {
+ printf("pmbus: invalid value '%s'\n", argv[2]);
+ return CMD_RET_USAGE;
+ }
+ if (argc >= 4)
+ fmt = argv[3];
+
+ if (!strcmp(fmt, "b")) {
+ if (val > 0xff) {
+ printf("pmbus: byte value out of range\n");
+ return CMD_RET_USAGE;
+ }
+ b = (u8)val;
+ ret = dm_i2c_write(chip, reg, &b, 1);
+ } else if (!strcmp(fmt, "w")) {
+ if (val > 0xffff) {
+ printf("pmbus: word value out of range\n");
+ return CMD_RET_USAGE;
+ }
+ buf[0] = (u8)(val & 0xff);
+ buf[1] = (u8)((val >> 8) & 0xff);
+ ret = dm_i2c_write(chip, reg, buf, 2);
+ } else {
+ printf("pmbus: unknown format '%s' (expected b or w)\n", fmt);
+ return CMD_RET_USAGE;
+ }
+ if (ret) {
+ printf("pmbus: write 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: wrote 0x%lx to %02xh (%s)\n", val, reg, pmbus_reg_name(reg));
+ return CMD_RET_SUCCESS;
+}
+
+static int do_clear(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc, ret;
+
+ if (argc >= 2 && strcmp(argv[1], "faults") != 0) {
+ printf("pmbus: unknown clear subcommand '%s' (expected 'faults')\n",
+ argv[1]);
+ return CMD_RET_USAGE;
+ }
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ ret = pmbus_clear_faults(chip);
+ if (ret) {
+ printf("pmbus: CLEAR_FAULTS (03h) failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: CLEAR_FAULTS (03h) issued (RAM sticky STATUS_* cleared)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_vout(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ u8 vout_mode = 0;
+ u16 raw;
+ s64 uv;
+ int rc, ret;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ if (pmbus_read_byte(chip, PMBUS_VOUT_MODE, &vout_mode)) {
+ printf("pmbus: VOUT_MODE read failed\n");
+ return CMD_RET_FAILURE;
+ }
+
+ if (argc < 2) {
+ if (pmbus_read_word(chip, PMBUS_READ_VOUT, &raw)) {
+ printf("pmbus: READ_VOUT failed\n");
+ return CMD_RET_FAILURE;
+ }
+ if (act->info)
+ uv = pmbus_reg2data(act->info, PSC_VOLTAGE_OUT, raw, vout_mode);
+ else
+ uv = pmbus_reg2data_linear16(raw, vout_mode);
+ printf("pmbus VOUT @ i2c%d:0x%02x raw=0x%04x ",
+ act->bus_seq, act->addr, raw);
+ print_micro(uv, "V");
+ printf("\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ {
+ unsigned long target_uv;
+ const char *fmt_name;
+ u8 buf[2];
+
+ if (strict_strtoul(argv[1], 0, &target_uv)) {
+ printf("pmbus: invalid microvolt value '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ raw = pmbus_data2reg_linear16((s64)target_uv, vout_mode);
+ fmt_name = "LINEAR16";
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ if (!act->info ||
+ act->info->format[PSC_VOLTAGE_OUT] != pmbus_fmt_direct) {
+ printf("pmbus: VOUT_MODE selects DIRECT but the active driver_info has no DIRECT coefficients for VOLTAGE_OUT\n");
+ return CMD_RET_FAILURE;
+ }
+ raw = pmbus_data2reg_direct((s64)target_uv,
+ act->info->m[PSC_VOLTAGE_OUT],
+ act->info->b[PSC_VOLTAGE_OUT],
+ act->info->R[PSC_VOLTAGE_OUT]);
+ fmt_name = "DIRECT";
+ break;
+ default:
+ printf("pmbus: VOUT_MODE 0x%02x selects an encoder not yet implemented (VID / IEEE754)\n",
+ vout_mode);
+ return CMD_RET_FAILURE;
+ }
+
+ buf[0] = raw & 0xff;
+ buf[1] = (raw >> 8) & 0xff;
+ ret = dm_i2c_write(chip, PMBUS_VOUT_COMMAND, buf, 2);
+ if (ret) {
+ printf("pmbus: VOUT_COMMAND write failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: VOUT_COMMAND <- 0x%04x (%s, target %lu uV)\n",
+ raw, fmt_name, target_uv);
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int pmbus_scan_one_bus(struct udevice *bus, int bus_seq)
+{
+ int hits = 0;
+ int addr;
+
+ for (addr = 0x08; addr <= 0x77; addr++) {
+ struct udevice *chip;
+ u8 b;
+
+ if (i2c_get_chip(bus, addr, 1, &chip))
+ continue;
+ /* MFR_ID block read: 1st byte is the length of the string. */
+ if (dm_i2c_read(chip, PMBUS_MFR_ID, &b, 1))
+ continue;
+ if (b >= 1 && b <= PMBUS_MFR_STRING_MAX - 1) {
+ char s[PMBUS_MFR_STRING_MAX] = "";
+
+ pmbus_read_string(chip, PMBUS_MFR_ID, s, sizeof(s), false);
+ if (!s[0])
+ pmbus_read_string(chip, PMBUS_MFR_ID, s, sizeof(s), true);
+ printf(" i2c%d:0x%02x MFR_ID=\"%s\"\n",
+ bus_seq, addr, s[0] ? s : "(unprintable)");
+ hits++;
+ }
+ }
+ return hits;
+}
+
+static int do_scan(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ int total = 0;
+
+ if (argc >= 2) {
+ struct udevice *bus;
+ unsigned long val;
+ int bus_seq;
+
+ if (strict_strtoul(argv[1], 0, &val)) {
+ printf("pmbus: invalid bus seq '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ bus_seq = (int)val;
+ if (uclass_get_device_by_seq(UCLASS_I2C, bus_seq, &bus)) {
+ printf("pmbus: i2c%d not available\n", bus_seq);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus scan i2c%d:\n", bus_seq);
+ total = pmbus_scan_one_bus(bus, bus_seq);
+ } else {
+ struct uclass *uc;
+ struct udevice *bus;
+
+ if (uclass_get(UCLASS_I2C, &uc))
+ return CMD_RET_FAILURE;
+ uclass_foreach_dev(bus, uc) {
+ int seq = dev_seq(bus);
+
+ if (seq < 0)
+ continue;
+ printf("pmbus scan i2c%d:\n", seq);
+ total += pmbus_scan_one_bus(bus, seq);
+ }
+ }
+ if (!total)
+ printf("pmbus: no PMBus responders found\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_help(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ unsigned int i, n = pmbus_vendor_count();
+
+ if (n == 0) {
+ printf("pmbus: no vendor extensions registered.\n");
+ printf(" Vendor handlers are registered by per chip drivers at\n");
+ printf(" probe time; trigger a probe via 'pmbus dev <name>' or a\n");
+ printf(" board hook (boot snapshot) and re run 'pmbus help'.\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ printf("Registered pmbus vendor extensions (%u):\n\n", n);
+ for (i = 0; i < n; i++) {
+ const struct pmbus_vendor_op *op = pmbus_vendor_at(i);
+
+ if (!op)
+ continue;
+ printf("[vendor: %s]\n", op->vendor);
+ if (op->help)
+ printf("%s", op->help);
+ printf("\n");
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static struct cmd_tbl pmbus_subcmd[] = {
+ U_BOOT_CMD_MKENT(dev, 2, 1, do_dev, "", ""),
+ U_BOOT_CMD_MKENT(list, 1, 1, do_list, "", ""),
+ U_BOOT_CMD_MKENT(info, 1, 1, do_info, "", ""),
+ U_BOOT_CMD_MKENT(telemetry, 1, 1, do_telemetry, "", ""),
+ U_BOOT_CMD_MKENT(status, 1, 1, do_status, "", ""),
+ U_BOOT_CMD_MKENT(dump, 1, 1, do_dump, "", ""),
+ U_BOOT_CMD_MKENT(read, 3, 1, do_read, "", ""),
+ U_BOOT_CMD_MKENT(write, 4, 1, do_write, "", ""),
+ U_BOOT_CMD_MKENT(clear, 2, 1, do_clear, "", ""),
+ U_BOOT_CMD_MKENT(vout, 2, 1, do_vout, "", ""),
+ U_BOOT_CMD_MKENT(scan, 2, 1, do_scan, "", ""),
+ U_BOOT_CMD_MKENT(help, 1, 1, do_help, "", ""),
+};
+
+static int do_pmbus(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_vendor_op *vop;
+ struct cmd_tbl *cmd;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+
+ argc--;
+ argv++;
+
+ cmd = find_cmd_tbl(argv[0], pmbus_subcmd, ARRAY_SIZE(pmbus_subcmd));
+ if (cmd) {
+ if (argc > cmd->maxargs)
+ return CMD_RET_USAGE;
+ return cmd->cmd(cmdtp, flag, argc, argv);
+ }
+
+ /* Vendor namespace dispatch */
+ vop = pmbus_lookup_vendor(argv[0]);
+ if (vop)
+ return vop->handler(cmdtp, flag, argc, argv);
+
+ printf("pmbus: unknown subcommand '%s'\n", argv[0]);
+ return CMD_RET_USAGE;
+}
+
+U_BOOT_CMD(pmbus, CONFIG_SYS_MAXARGS, 1, do_pmbus,
+ "PMBus 1.x device interrogation and control",
+ "list - list UCLASS_REGULATOR devices (DM bound)\n"
+ "pmbus dev [<bus>:<addr>|<name>] - show / select active PMBus device\n"
+ "pmbus info - identification banner + driver_info\n"
+ "pmbus telemetry - decoded VIN, VOUT, IIN, IOUT, TEMP\n"
+ "pmbus status - decode every STATUS_* register\n"
+ "pmbus dump - hex dump of every standard register\n"
+ "pmbus read <reg> [b|w|s] - raw read (b=byte, w=word, s=string)\n"
+ "pmbus write <reg> <val> [b|w] - raw write\n"
+ "pmbus clear [faults] - issue CLEAR_FAULTS (03h)\n"
+ "pmbus vout [<uV>] - read / set VOUT_COMMAND (microvolts)\n"
+ "pmbus scan [<bus>] - PMBus aware probe of one or all I2C buses\n"
+ "pmbus help - list registered vendor extensions\n"
+ "\n"
+ "Vendor extensions (pmbus <vendor> ...) are registered by per chip\n"
+ "drivers at probe time. Run 'pmbus help' after a chip is probed to\n"
+ "see the available subcommands.\n"
+);
diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index 3c044e67927..2ce67b7bfe2 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -50,6 +50,7 @@ Implementation
logging
makefiles
menus
+ pmbus
printf
smbios
spl
diff --git a/doc/develop/pmbus.rst b/doc/develop/pmbus.rst
new file mode 100644
index 00000000000..270c1118ce2
--- /dev/null
+++ b/doc/develop/pmbus.rst
@@ -0,0 +1,636 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+PMBus support in U-Boot
+=======================
+
+This document describes U-Boot's PMBus 1.x support: what it is for,
+how it is structured, and how to add support for a new PMBus chipn
+either from scratch from a chip datasheet or by porting an existing
+Linux ``drivers/hwmon/pmbus/`` driver.
+
+.. contents::
+ :local:
+ :depth: 2
+
+Intent and scope
+----------------
+
+U-Boot's PMBus layer is not a hardware monitoring (hwmon) clone of
+the Linux kernel's ``drivers/hwmon/pmbus/`` subsystem. Linux owns the
+runtime side: continuous polling, sysfs publication, alert IRQ
+handling, fan control loops. U-Boot owns the boot time side. Concretely
+the U-Boot PMBus support exists to:
+
+* Identify the PMBus regulator(s) a board carries at boot:
+ ``MFR_ID``, ``MFR_MODEL``, ``MFR_REVISION`` reads, plus a quick
+ ``STATUS_WORD`` sanity check.
+* Print telemetry so an operator can confirm rail voltages, input
+ current, and temperature before handing off to the kernel. One shot
+ reads, on demand, via the ``pmbus`` and ``regulator`` U-Boot
+ commands (``pmbus dev <name>; pmbus telemetry``,
+ ``regulator dev <name>; regulator value``).
+* Decode chip alerts when a rail trips an over/under voltage,
+ over current, or thermal threshold; so a boot log shows why the
+ previous boot failed, before the kernel even comes up.
+* Optionally trim a critical rail (typically the SoC core) before
+ the kernel takes over; "set the voltage prior to a kernel boot
+ to better protect the board". This is the existing
+ ``board/nxp/common/vid.c`` AVS path and any future per board
+ speed binning trim.
+
+Out of scope, by design:
+
+* No periodic polling. No worker thread. No background updates.
+* No sysfs / procfs / userspace surface. U-Boot has none.
+* No fan speed control loop. The kernel runs that.
+* No long tail of virtual sensor registers (``PMBUS_VIRT_*``).
+* No sensor caching / update timestamps.
+
+If you find yourself wanting any of those, the answer is "wait until
+Linux comes up". Keep U-Boot's PMBus surface minimal.
+
+Architecture overview
+---------------------
+
+The framework is split into four layers (layer 3 comes in two
+flavours, 3a and 3b),
+
+::
+
+ +----------------------------------------+
+ | Layer 1: include/pmbus.h |
+ | Standard PMBus 1.x command codes, |
+ | numeric format enum, sensor class |
+ | enum, struct pmbus_driver_info, |
+ | decoder + transport prototypes, |
+ | STATUS_WORD bit names. |
+ +----------------------------------------+
+ | Layer 2: lib/pmbus.c |
+ | Format decoders (LINEAR11/LINEAR16/|
+ | DIRECT) and encoder (LINEAR16), |
+ | two stage SMBus block read helper, |
+ | STATUS_*-bit print tables, generic |
+ | dispatcher pmbus_reg2data(). |
+ +----------------------------------------+
+ | Layer 3a: drivers/power/regulator/ |
+ | <chip>.c |
+ | UCLASS_REGULATOR per chip drivers |
+ | ; one struct pmbus_driver_info |
+ | plus regulator set_value/get_value |
+ | ops. Optional: per chip identify() |
+ | hook to refine format from the |
+ | chip's own VOUT_MODE. |
+ +----------------------------------------+
+ | Layer 3b: drivers/power/regulator/ |
+ | pmbus_generic.c |
+ | Catch all driver matching |
+ | compatible = "pmbus". |
+ | Auto detects format via VOUT_MODE |
+ | and PMBUS_QUERY where supported. |
+ | Use for compliant chips with no |
+ | per chip driver yet; ship |
+ | telemetry today, write a per chip |
+ | driver later only if quirks demand |
+ | it. |
+ +----------------------------------------+
+ | Layer 4: board/<vendor>/<board>/ |
+ | <chip>_diag.c |
+ | Diagnostic commands only: |
+ | <chip>_info / <chip>_raw |
+ | Reads via regulator_get_value() |
+ | and lib/pmbus.c helpers. LINEAR / |
+ | DIRECT math NOT here. |
+ +----------------------------------------+
+
+Generic vs. board specific separation rule. Layer 1, 2, and 3
+files are tree level and platform agnostic. Their comments may
+reference only:
+
+* the PMBus 1.x specification, and
+* chip manufacturer datasheets.
+
+Never a specific board, SoC, or product. Board-specific quirks
+(a particular bus number, a particular slave address, a particular
+PCB feedback divider, board local design notes) live exclusively in
+``board/<vendor>/<board>/`` files.
+
+CLI commands
+------------
+
+The framework publishes one top level command, ``pmbus``, plus a
+vendor namespace dispatcher so per chip code can register chip
+specific extensions without touching the framework.
+
+Active device model
+~~~~~~~~~~~~~~~~~~~
+
+``pmbus`` mirrors the ``regulator`` command: select an active device
+once, then operate on it across subcommands. The active device is
+selected by I2C bus and 7 bit address::
+
+ => pmbus dev 0:0x10
+ pmbus: active i2c0:0x10 MFR_ID="MPS" MFR_MODEL="MPQ8785" vendor=mps
+
+The framework probes ``MFR_ID`` (in both natural and reverse byte
+orders) at selection time, looks the result up in the chip match
+registry populated by per chip code via ``pmbus_register_chip()``,
+and caches the matched ``pmbus_driver_info``. All subsequent
+subcommands consume that cached metadata.
+
+Standard subcommands
+~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ pmbus list list UCLASS_REGULATOR devices (DM bound)
+ pmbus dev [<bus>:<addr>] show / select active PMBus device
+ pmbus info identification banner + driver_info
+ pmbus telemetry decoded VIN, VOUT, IIN, IOUT, TEMP
+ pmbus status decode every STATUS_* register
+ pmbus dump hex dump of every standard register
+ pmbus read <reg> [b|w|s] raw read (b=byte, w=word, s=string)
+ pmbus write <reg> <val> [b|w] raw write
+ pmbus clear [faults] issue CLEAR_FAULTS (03h)
+ pmbus vout [<uV>] read or set VOUT_COMMAND (microvolts)
+ pmbus scan [<bus>] PMBus aware probe of one or all I2C buses
+
+The ``<reg>`` argument accepts either a hexadecimal address
+(``0x88``) or a symbolic name (``READ_VIN``, ``VOUT_MODE``,
+``MFR_ID``). Format selectors after the register select the SMBus
+transaction width: ``b`` for byte, ``w`` for 16 bit little endian
+word, ``s`` for the SMBus block read used by string registers.
+
+Decoded telemetry honours the active device's ``pmbus_driver_info``;
+when no chip match has been registered, VOUT falls back to LINEAR16
+driven by ``VOUT_MODE`` and the other sensors fall back to LINEAR11.
+
+Vendor namespace
+~~~~~~~~~~~~~~~~
+
+Per chip drivers and board files publish chip specific subcommands
+in the ``pmbus <vendor> ...`` namespace by calling
+``pmbus_register_vendor_handler()`` at init time. The framework
+dispatches ``pmbus mps last``, ``pmbus mps clear last``, and
+``pmbus mps clear force`` to the MPS handler when the active
+device matches the ``mps`` vendor. Additional vendor handlers for
+``lltc``, ``renesas``, etc. land alongside the per chip drivers
+that need them.
+
+Relationship to ``vdd_override`` / ``vdd_read``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The NXP Layerscape ``vdd_override <mV>`` and ``vdd_read`` commands
+remain available in their original form for compatibility with
+existing AVS production scripts. The new ``pmbus vout`` and
+``pmbus vout <uV>`` subcommands cover the read and single shot
+write paths against the same chips, but do not implement
+``vdd_override``'s full sequence (board drop compensation, fuse
+target derivation, multi step convergence loop, atomic
+``PAGE_PLUS_WRITE`` block transaction, ``WRITE_PROTECT`` dance).
+For interactive bring up ``pmbus vout`` is sufficient; for
+production AVS, ``vdd_override`` stays canonical.
+
+Lifecycle: from board boot to Linux handoff
+-------------------------------------------
+
+The PMBus framework spans the entire U-Boot lifecycle. This section
+walks the boot timeline phase by phase, showing when each piece
+comes online and how the regulator uclass and the ``pmbus`` CLI
+converge on the same chip.
+
+Timeline overview
+~~~~~~~~~~~~~~~~~
+
+::
+
+ Phase 0 chip power on chip ramps to NVM default VOUT
+ Phase 1 boot ROM / SPL / TF-A PMBus typically untouched
+ Phase 2 U-Boot relocation, DM init regulators bound, not probed
+ Phase 3 first regulator probe chip driver runs, framework lights up
+ Phase 4 board hooks / boot scripts snapshot, AVS trim, gating
+ Phase 5 Linux handoff DT passed, chip state preserved
+ Phase 6 Linux runtime kernel pmbus driver takes over
+
+Phase 0: chip power on
+~~~~~~~~~~~~~~~~~~~~~~
+
+When the regulator chip receives its input voltage, it ramps its
+output to the VOUT default programmed into its NVM at factory
+provisioning. PMBus is silent: no software runs anywhere on the
+SoC yet.
+
+Phase 1: pre U-Boot stages
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boot ROMs, secondary boot loaders (SPL, ARM TF-A BL2 / BL31)
+typically do not touch PMBus. They focus on PLLs, DDR PHY init,
+and bringing up enough hardware to load the next stage. Some
+platforms have a pre U-Boot AVS path in board specific TF-A
+code that writes ``VOUT_COMMAND`` from a fuse derived target;
+that path is independent of the U-Boot framework described here.
+
+Phase 2: U-Boot relocation and DM init
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+After relocation, U-Boot binds device tree nodes to drivers but
+does not probe them. UCLASS_REGULATOR devices for PMBus chips
+are bound (driver and DT match resolved) but the ``.probe``
+callback has not run yet.
+
+Framework state at this point:
+
+* chip match registry: empty
+* vendor handler registry: empty
+* active device: none
+* regulator uclass: devices bound, none probed
+
+Phase 3: lazy regulator probe
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The first caller into the regulator uclass for a given chip
+triggers the chip driver's ``.probe``. Typical first callers:
+
+* a board ``EVENT_SPY`` at ``EVT_LAST_STAGE_INIT`` (boot snapshot)
+* a U-Boot script: ``regulator dev <name>; regulator value``
+* the ``pmbus dev <name>`` CLI command (resolves to the regulator)
+* another DT consumer with a ``regulator-supplies`` reference
+
+The probe chain looks like this::
+
+ <chip>_probe(dev)
+ pmbus_regulator_probe_common(dev, &<chip>_info, page)
+ dev_read_addr(dev) -> reg = <addr>
+ i2c_get_chip(dev->parent, addr) -> I2C chip handle
+ priv->i2c_dev = handle
+ priv->info = &<chip>_info
+ priv->page = page
+ (page > 0) write PMBUS_PAGE
+ <chip>_identify_vout(priv->i2c_dev) [optional]
+ read VOUT_MODE; refine info->format[PSC_VOLTAGE_OUT]
+ pmbus_regulator_apply_voltage_scale(dev, fb_div) [optional]
+ write PMBUS_VOUT_SCALE_LOOP if DT property set
+ pmbus_register_chip(&<chip>_match) [idempotent]
+ pmbus_register_vendor_handler(&<chip>_op) [idempotent]
+
+Once probed, three independent surfaces are functional against
+the same chip:
+
+* the regulator uclass API (``regulator_get_value``,
+ ``regulator_set_value``, ``regulator_get_enable``,
+ ``regulator_set_enable``)
+* the ``pmbus`` CLI (chip is reachable by name through
+ ``pmbus_resolve_by_name()``, by raw ``<bus>:<addr>`` through
+ ``pmbus_set_active()``)
+* the chip's vendor extension subcommands (``pmbus <vendor> ...``)
+
+Phase 4: board hooks and boot scripts
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boards hook the boot flow at well known points to drive board
+specific PMBus behaviour. The framework prescribes none of these;
+they are conventions:
+
+* boot time rail snapshot. An ``EVENT_SPY`` at
+ ``EVT_LAST_STAGE_INIT`` reads telemetry through the regulator
+ uclass and prints a one shot summary to the console. Useful
+ for operator visibility on serial during bring up.
+
+* pre kernel rail trim (AVS). A board hook in
+ ``board_late_init`` or a custom event spy reads a fuse derived
+ target voltage and calls ``regulator_set_value_force()`` to
+ trim the SoC core rail before kernel handoff.
+
+* Linux handoff gate. A bootcmd reads the rail voltage
+ through the regulator command and refuses to boot Linux if
+ the rail is outside the expected range.
+
+Phase 5: Linux handoff
+~~~~~~~~~~~~~~~~~~~~~~
+
+When U-Boot transfers control to Linux, it passes the device
+tree (potentially patched). The DT compatible strings for PMBus
+regulators must match those in the upstream kernel binding so
+the kernel's ``drivers/hwmon/pmbus/<chip>.c`` picks them up.
+Property names are shared with the kernel binding
+(``regulator-name``, ``regulator-min-microvolt``,
+``mps,vout-fb-divider-ratio-permille``, etc.); see "DT alignment
+with Linux" below.
+
+The chip itself is left in the state U-Boot wrote it to. If
+U-Boot trimmed VOUT, the chip stays at the trimmed voltage
+through handoff. ``CLEAR_FAULTS`` state is preserved unless an
+operator explicitly issued one.
+
+Phase 6: Linux runtime
+~~~~~~~~~~~~~~~~~~~~~~
+
+Linux's ``drivers/hwmon/pmbus/pmbus_core.c`` probes the chip,
+exposes telemetry under ``/sys/class/hwmon``, and takes over
+runtime voltage management through its regulator subsystem.
+The hwmon framework polls periodically; U-Boot does not.
+
+Operation paths through the regulator uclass
+--------------------------------------------
+
+After the first probe completes, calls into the regulator uclass
+for a PMBus chip flow through the shared helper.
+
+Read VOUT::
+
+ regulator_get_value(dev)
+ -> dm_regulator_ops->get_value
+ -> pmbus_regulator_get_value(dev)
+ pmbus_regulator_select_page(priv)
+ pmbus_read_byte(priv->i2c_dev, VOUT_MODE, &mode)
+ pmbus_read_word(priv->i2c_dev, READ_VOUT, &raw)
+ pmbus_reg2data(priv->info, PSC_VOLTAGE_OUT, raw, mode)
+ -> reg2data_linear16 (mode = 0)
+ -> reg2data_direct (chip configured for DIRECT)
+ return engineering value (microvolts)
+
+Write VOUT::
+
+ regulator_set_value(dev, uV)
+ -> dm_regulator_ops->set_value
+ -> pmbus_regulator_set_value(dev, uV)
+ pmbus_regulator_select_page(priv)
+ pmbus_read_byte(VOUT_MODE)
+ check (mode == LINEAR) [LINEAR16 only today]
+ raw = pmbus_data2reg_linear16(uV, mode)
+ dm_i2c_write(VOUT_COMMAND, raw)
+
+Read / write enable bit::
+
+ regulator_get_enable(dev)
+ -> pmbus_regulator_get_enable(dev)
+ pmbus_read_byte(OPERATION) & PB_OPERATION_ON
+
+ regulator_set_enable(dev, on)
+ -> pmbus_regulator_set_enable(dev, on)
+ read OPERATION, set or clear PB_OPERATION_ON, write back
+
+Bus traffic per call:
+
+* ``get_value`` : 1 byte read (VOUT_MODE) + 1 word read (READ_VOUT)
+ + 1 byte write (PAGE) when ``page > 0``
+* ``set_value`` : 1 byte read (VOUT_MODE) + 1 word write (VOUT_COMMAND)
+ + 1 byte write (PAGE) when ``page > 0``
+* ``get_enable`` : 1 byte read (OPERATION)
+* ``set_enable`` : 1 byte read (OPERATION) + 1 byte write (OPERATION)
+
+Common board hook patterns
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boot time rail snapshot::
+
+ static int my_board_pmbus_snapshot(void)
+ {
+ struct udevice *reg;
+
+ if (regulator_get_by_platname("MY_RAIL", ®))
+ return 0;
+ printf("MY_RAIL: VOUT = %d uV, enabled = %d\n",
+ regulator_get_value(reg),
+ regulator_get_enable(reg));
+ return 0;
+ }
+ EVENT_SPY_SIMPLE(EVT_LAST_STAGE_INIT, my_board_pmbus_snapshot);
+
+The first call to ``regulator_get_value()`` triggers the chip
+driver's ``.probe``, which seeds the chip match and vendor
+extension registries. Subsequent ``pmbus`` CLI commands work
+without further setup.
+
+Pre kernel rail trim (AVS)::
+
+ int board_late_init(void)
+ {
+ struct udevice *reg;
+ int target_uV = compute_avs_target();
+
+ if (regulator_get_by_platname("VDD_CORE", ®))
+ return 0;
+ return regulator_set_value_force(reg, target_uV);
+ }
+
+Use ``regulator_set_value_force()`` when the target may sit
+outside the DT declared ``regulator-min-microvolt`` /
+``regulator-max-microvolt`` range; force bypasses the bounds
+check.
+
+Adding a new PMBus chip from scratch
+------------------------------------
+
+Use this path when the chip has no Linux driver yet, or when you want
+to validate the U-Boot port against the datasheet alone.
+
+1. Confirm PMBus 1.x compliance level. Locate in the chip
+ datasheet:
+
+ which PMBus standard command codes the chip implements
+ (``READ_VIN``, ``READ_VOUT``, ``STATUS_WORD``, ``MFR_ID`` ...),
+ which numeric format(s) it uses for VOUT (LINEAR16 with the
+ exponent in ``VOUT_MODE``, DIRECT with chip specific m/b/R, or
+ VID with one of the documented VRM tables),
+ which numeric format it uses for VIN, IIN, IOUT, TEMPERATURE
+ (most commonly LINEAR11; some MPS / MPS derivative chips use
+ DIRECT instead),
+ how many output rails it exposes (single page parts vs.
+ multi rail PMBus pages).
+
+2. Declare a ``struct pmbus_driver_info``. Wire each sensor
+ class to one ``enum pmbus_data_format``, plus the m/b/R triple if
+ the format is DIRECT::
+
+ static struct pmbus_driver_info chipname_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_direct,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear,
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_direct,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_IN] = 4, .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_CURRENT_OUT] = 16, .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_TEMPERATURE] = 1, .R[PSC_TEMPERATURE] = 0,
+ };
+
+3. Bind to a DT compatible. Use the lowercase ``vendor,chip``
+ tuple Linux uses (see "DT alignment with Linux" below). Add the
+ driver under ``drivers/power/regulator/`` matching the existing
+ skeleton (``fan53555.c``, ``pca9450.c``).
+
+4. Add a YAML schema under
+ ``doc/device-tree-bindings/regulator/<vendor>,<chip>.yaml``.
+ Mirror the upstream Linux binding when it exists; cross reference
+ the kernel YAML in the schema description.
+
+5. Smoke test. With the chip wired up in DT::
+
+ => regulator dev <name>
+ => regulator value
+ => regulator info
+
+ Numbers should match the bench measurement to within the chip's
+ advertised LSB.
+
+Porting an existing Linux PMBus driver to U-Boot
+------------------------------------------------
+
+When the chip already has a ``linux/drivers/hwmon/pmbus/<chip>.c``,
+that driver is the authoritative reference for format, coefficients,
+and quirks. Take what carries; leave what does not.
+
+What carries verbatim
+~~~~~~~~~~~~~~~~~~~~~
+
+* Numeric formats (``format[PSC_*]``).
+* DIRECT coefficients (``m[]``, ``b[]``, ``R[]``).
+* Per page count and per page functionality bits (``pages``,
+ ``func[]``).
+* VOUT_MODE driven per chip identify hook (e.g. MPQ8785's
+ switch between LINEAR16 and VID coerced DIRECT m=64 R=1).
+* Vendor register addresses for chip specific quirks (fault
+ history, scale-loop, page mapping).
+
+What does not carry
+~~~~~~~~~~~~~~~~~~~~~~~
+
+* ``hwmon_device_register()`` and the attribute groups it consumes.
+* ``struct pmbus_data`` / ``update_lock`` / ``last_updated``
+ U-Boot has no caching layer.
+* ALERT# IRQ wiring; U-Boot is single threaded boot code.
+* Fan control hooks (``read_fan_*``, ``set_pwm_*``).
+* Virtual register handling (``PMBUS_VIRT_READ_VIN_*`` etc.); those
+ are entirely a hwmon publication aid.
+* ``module_i2c_driver(...)`` and ``MODULE_*`` macros; U-Boot uses
+ ``U_BOOT_DRIVER(...)``.
+
+Worked example: porting MPQ8785
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Linux's ``drivers/hwmon/pmbus/mpq8785.c`` is 193 LOC; the U-Boot
+equivalent is ~150 LOC.
+
+The ``mpq8785_info`` struct transcribes verbatim::
+
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = direct, .m[PSC_VOLTAGE_IN] = 4, .R[PSC_VOLTAGE_IN] = 1,
+ .format[PSC_CURRENT_OUT] = direct, .m[PSC_CURRENT_OUT] = 16, .R[PSC_CURRENT_OUT] = 0,
+ .format[PSC_TEMPERATURE] = direct, .m[PSC_TEMPERATURE] = 1, .R[PSC_TEMPERATURE] = 0,
+
+The VOUT format is decided at probe time from VOUT_MODE bits[7:5] :
+mode 0 means LINEAR16, mode 1 or 2 means DIRECT m=64 R=1 (the chip's
+"VID" mode is coerced to DIRECT by the driver). Translate Linux's
+``mpq8785_identify()`` 1:1.
+
+The per chip quirks that carry over:
+
+* MPS NVM string byte order: chip stores ``S P M`` for the human
+ string ``MPS``. ``pmbus_read_string()`` accepts a ``reverse_bytes``
+ flag for this case.
+* ``mps,vout-fb-divider-ratio-permille`` DT property maps to
+ ``VOUT_SCALE_LOOP`` write at probe time.
+
+The quirks that do not carry over:
+
+* The ``PMBUS_VIRT_*`` virtual sensor wiring. Drop entirely.
+* The ``hwmon_chip_info`` attribute group registration.
+* The ``MODULE_AUTHOR`` / ``MODULE_LICENSE`` declarations.
+
+Using the generic ``compatible = "pmbus"`` driver
+-------------------------------------------------
+
+When a board carries a PMBus chip without a per chip U-Boot driver,
+the catch all ``drivers/power/regulator/pmbus_generic.c`` (Layer 3b)
+binds against ``compatible = "pmbus"``. It auto detects format via
+``VOUT_MODE`` and ``PMBUS_QUERY`` (where the chip supports it) and
+provides telemetry + voltage set/get against the standard PMBus 1.x
+subset.
+
+Decision tree:
+
+1. Try the generic driver first. Add the regulator node to the
+ board DT with ``compatible = "pmbus"`` plus the standard
+ regulator properties. Boot, run ``regulator value``, compare
+ against bench measurement.
+2. Switch to a per chip driver only when the generic one is
+ wrong: telemetry shows wrong values (chip uses DIRECT with
+ non default coefficients), an alert can't be decoded (chip has
+ vendor specific status bits), AVS is needed (the boot path has
+ to actively trim VOUT before kernel handoff), or the chip has an
+ ADDR-pin auto promotion / VID coercion / vendor register quirk.
+
+DT alignment with Linux
+-----------------------
+
+The same ``.dts`` file should work under both U-Boot (BL33) and Linux
+post handoff. To make that possible:
+
+* Reuse the upstream Linux compatible for every PMBus chip. Look
+ in ``linux/Documentation/devicetree/bindings/hwmon/pmbus/`` and
+ ``linux/Documentation/devicetree/bindings/regulator/``. The
+ ``<vendor>,<chip>`` tuple from the kernel binding goes into U-Boot's
+ ``of_match_table`` unchanged.
+* Reuse Linux property names verbatim: ``regulator-name``,
+ ``regulator-min-microvolt``, ``regulator-max-microvolt``,
+ ``regulator-boot-on``, ``regulator-always-on``,
+ ``mps,vout-fb-divider-ratio-permille``, etc.
+* Mirror the Linux YAML schema as
+ ``doc/device-tree-bindings/regulator/<vendor>,<chip>.yaml``. The
+ U-Boot schema can be a strict subset (drop hwmon only properties
+ that have no U-Boot effect), and should cite the kernel YAML as the
+ canonical source.
+
+Multi rail/multi page chips (e.g. ISL68137 with seven outputs)
+declare each rail as a child regulator node with ``reg = <page>``;
+each child binds as a UCLASS_REGULATOR with that PMBus PAGE setting
+applied at every read/write.
+
+Common pitfalls
+---------------
+
+These have all bitten contributors during nbxv3 bring up; record them
+here so the next port doesn't repeat them.
+
+* VOUT_MODE/DIRECT format confusion. Most generic PMBus call
+ sites assume LINEAR16. Several MPS chips report VOUT in DIRECT
+ format with chip specific m/b/R after a single VOUT_MODE read,
+ the same chip read at the same address produces different
+ numbers depending on the format the driver applies. Always read
+ ``VOUT_MODE`` at probe time and switch the decoder accordingly.
+ Linux's per chip ``identify()`` callbacks document the exact
+ rules; copy them rather than guessing.
+* SMBus block read protocol. Some I2C controllers strict check
+ block read transactions: the master must read the length byte
+ first, then reissue the read for the payload. Over reading a
+ fixed length and ignoring the length byte works on lenient
+ controllers but errors on strict ones. ``pmbus_read_string()``
+ does the two stage read; use it.
+* I2C bus number stability. ``uclass_get_device_by_seq()``
+ uses the DT alias index (``i2c0`` -> ``UCLASS_I2C`` seq 0) when
+ aliases are declared, otherwise falls back to probe order which
+ varies with which controllers are enabled in the defconfig.
+ Always declare DT aliases for I2C buses you reference by index.
+* ADDR-pin auto addressessing. Some chips (notably MPS parts) decode
+ their PMBus 7-bit address from an external resistor divider on
+ ADDR_VBOOT. The "default" address in the datasheet is the
+ factory fused slot; a board with a different divider or a die
+ with a different revision can land in another window. If the
+ driver hardcodes the default and the board side scan finds the
+ chip in another window, auto promote the working address rather
+ than failing the probe.
+* MFR string byte order. Most PMBus chips return ``MFR_ID``
+ characters in human order. Some MPS personalities reverse them.
+ Pass ``reverse_bytes=true`` to ``pmbus_read_string()`` for those;
+ spec compliant chips pass false.
+
+References
+----------
+
+* Linux PMBus core: ``linux/drivers/hwmon/pmbus/pmbus_core.c``,
+ decoder reference; ignore the hwmon publication and caching layers.
+* Linux PMBus header: ``linux/drivers/hwmon/pmbus/pmbus.h``; API
+ surface reference; many constants and the ``struct
+ pmbus_driver_info`` shape are mirrored verbatim into U-Boot's
+ ``include/pmbus.h``.
+* Linux DT bindings:
+ ``linux/Documentation/devicetree/bindings/hwmon/pmbus/``.
diff --git a/doc/device-tree-bindings/regulator/pmbus.yaml b/doc/device-tree-bindings/regulator/pmbus.yaml
new file mode 100644
index 00000000000..bcdf9c42f94
--- /dev/null
+++ b/doc/device-tree-bindings/regulator/pmbus.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/pmbus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic PMBus 1.x compatible voltage regulator (U-Boot subset)
+
+maintainers:
+ - Vincent Jardin <vjardin@free.fr>
+
+description: |
+ Catch all binding for any PMBus 1.x compliant voltage regulator that
+ does not yet have a per chip U-Boot driver under
+ drivers/power/regulator/. The matching driver auto detects the
+ numeric format from VOUT_MODE (and from PMBUS_QUERY where the chip
+ supports it) and provides telemetry plus voltage set / get against
+ the standard PMBus command codes (PMBUS_VOUT_MODE, PMBUS_VOUT_COMMAND,
+ PMBUS_READ_VOUT, ...).
+
+ This U-Boot subset mirrors the upstream Linux kernel pattern used
+ by linux/drivers/hwmon/pmbus/pmbus.c (the generic probe driver
+ matched against compatible "pmbus"). Property names and semantics
+ follow the standard regulator binding so the same .dts works under
+ both U-Boot (BL33) and Linux post handoff. Properties that only
+ affect the kernel hwmon publication are accepted and ignored.
+
+ Use this binding to ship telemetry today on a new board carrying a
+ compliant chip; promote to a per chip driver only when chip
+ specific quirks (vendor registers, VID coercion, ADDR pin auto
+ promotion, non standard m / b / R coefficients) need handling.
+
+allOf:
+ - $ref: regulator.yaml#
+
+properties:
+ compatible:
+ const: pmbus
+
+ reg:
+ maxItems: 1
+
+required:
+ - compatible
+ - reg
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ regulator@5e {
+ compatible = "pmbus";
+ reg = <0x5e>;
+ regulator-name = "VDD_CORE";
+ regulator-min-microvolt = < 600000>;
+ regulator-max-microvolt = <1100000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ };
+...
diff --git a/include/pmbus.h b/include/pmbus.h
new file mode 100644
index 00000000000..969108e5b53
--- /dev/null
+++ b/include/pmbus.h
@@ -0,0 +1,629 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * PMBus 1.x command codes, numeric format decoders, and driver_info
+ * scaffolding for U-Boot.
+ *
+ * Intents
+ *
+ * U-Boot's PMBus support is not a hwmon clone. It shall be used to:
+ * 1. identify PMBus regulators a board carries at boot,
+ * 2. print telemetry so an operator can confirm rail voltages and
+ * fault status before handing off to the kernel,
+ * 3. decode chip alerts when a rail trips an over/under voltage,
+ * over current, or thermal threshold,
+ * 4. optionally trim a critical rail before kernel boot, to better
+ * protect the board.
+ *
+ * No periodic polling, no /sys, no userspace surface, no fan control
+ * loops. Linux owns those. See doc/develop/pmbus.rst for the full
+ * porting guide and policy notes.
+ *
+ * Linux relationship
+ *
+ * Constants (command codes, status bit names, sensor class enum,
+ * format enum) are mirrored verbatim from
+ * linux/drivers/hwmon/pmbus/pmbus.h
+ * with attribution; this is standardised data and copying it avoids
+ * accidental drift. Decoders (LINEAR11/16, DIRECT, VID, IEEE754) are
+ * reimplemented from the PMBus 1.x spec rather than copied. The
+ * surrounding kernel context (struct pmbus_data, hwmon caching,
+ * sysfs publication) does not apply to U-Boot.
+ *
+ * Tree level files (this header, lib/pmbus.c, future per chip drivers
+ * under drivers/power/regulator/) must stay platform agnostic. They
+ * may reference only the PMBus 1.x specification and chip datasheets,
+ * never a specific board, SoC, or product. Board specific quirks
+ * live under board/<vendor>/<board>/.
+ */
+
+#ifndef _PMBUS_H_
+#define _PMBUS_H_
+
+#include <linux/types.h>
+
+struct udevice;
+struct pmbus_driver_info;
+struct pmbus_status_override;
+
+/*
+ * PMBus 1.3 standard command codes (Part II).
+ *
+ * Subset relevant to U-Boot's needs:
+ * - configuration (PAGE, OPERATION, VOUT_*),
+ * - telemetry (READ_VIN, READ_IOUT, READ_TEMPERATURE_1, ...),
+ * - status (STATUS_WORD, STATUS_VOUT, ...),
+ * - identification (MFR_ID, MFR_MODEL, MFR_REVISION).
+ * Chip specific extensions (for example MPS PROTECTION_LAST 0xFB) shall be in
+ * the per chip driver file.
+ */
+#define PMBUS_PAGE 0x00
+#define PMBUS_OPERATION 0x01
+#define PMBUS_ON_OFF_CONFIG 0x02
+#define PMBUS_CLEAR_FAULTS 0x03
+#define PMBUS_PHASE 0x04
+
+#define PMBUS_WRITE_PROTECT 0x10
+
+#define PMBUS_CAPABILITY 0x19
+#define PMBUS_QUERY 0x1a
+#define PMBUS_SMBALERT_MASK 0x1b
+#define PMBUS_VOUT_MODE 0x20
+#define PMBUS_VOUT_COMMAND 0x21
+#define PMBUS_VOUT_TRIM 0x22
+#define PMBUS_VOUT_CAL_OFFSET 0x23
+#define PMBUS_VOUT_MAX 0x24
+#define PMBUS_VOUT_MARGIN_HIGH 0x25
+#define PMBUS_VOUT_MARGIN_LOW 0x26
+#define PMBUS_VOUT_TRANSITION_RATE 0x27
+#define PMBUS_VOUT_DROOP 0x28
+#define PMBUS_VOUT_SCALE_LOOP 0x29
+#define PMBUS_VOUT_SCALE_MONITOR 0x2a
+
+#define PMBUS_COEFFICIENTS 0x30
+#define PMBUS_POUT_MAX 0x31
+
+#define PMBUS_STATUS_BYTE 0x78
+#define PMBUS_STATUS_WORD 0x79
+#define PMBUS_STATUS_VOUT 0x7a
+#define PMBUS_STATUS_IOUT 0x7b
+#define PMBUS_STATUS_INPUT 0x7c
+#define PMBUS_STATUS_TEMPERATURE 0x7d
+#define PMBUS_STATUS_CML 0x7e
+#define PMBUS_STATUS_OTHER 0x7f
+#define PMBUS_STATUS_MFR_SPECIFIC 0x80
+
+#define PMBUS_READ_VIN 0x88
+#define PMBUS_READ_IIN 0x89
+#define PMBUS_READ_VCAP 0x8a
+#define PMBUS_READ_VOUT 0x8b
+#define PMBUS_READ_IOUT 0x8c
+#define PMBUS_READ_TEMPERATURE_1 0x8d
+#define PMBUS_READ_TEMPERATURE_2 0x8e
+#define PMBUS_READ_TEMPERATURE_3 0x8f
+#define PMBUS_READ_DUTY_CYCLE 0x94
+#define PMBUS_READ_FREQUENCY 0x95
+#define PMBUS_READ_POUT 0x96
+#define PMBUS_READ_PIN 0x97
+
+#define PMBUS_REVISION 0x98
+#define PMBUS_MFR_ID 0x99
+#define PMBUS_MFR_MODEL 0x9a
+#define PMBUS_MFR_REVISION 0x9b
+#define PMBUS_MFR_LOCATION 0x9c
+#define PMBUS_MFR_DATE 0x9d
+#define PMBUS_MFR_SERIAL 0x9e
+
+#define PMBUS_IC_DEVICE_ID 0xad
+#define PMBUS_IC_DEVICE_REV 0xae
+
+/* VOUT_MODE upper bits: numeric format selector (Part II sec 8.3). */
+#define PB_VOUT_MODE_MODE_MASK 0xe0
+#define PB_VOUT_MODE_PARAM_MASK 0x1f
+#define PB_VOUT_MODE_LINEAR 0x00
+#define PB_VOUT_MODE_VID 0x20
+#define PB_VOUT_MODE_DIRECT 0x40
+#define PB_VOUT_MODE_IEEE754 0x60
+
+/* STATUS_WORD lower byte (= STATUS_BYTE), Part II sec 10.1.1. */
+#define PB_STATUS_NONE_ABOVE BIT(0)
+#define PB_STATUS_CML BIT(1)
+#define PB_STATUS_TEMPERATURE BIT(2)
+#define PB_STATUS_VIN_UV BIT(3)
+#define PB_STATUS_IOUT_OC BIT(4)
+#define PB_STATUS_VOUT_OV BIT(5)
+#define PB_STATUS_OFF BIT(6)
+#define PB_STATUS_BUSY BIT(7)
+
+/* STATUS_WORD upper byte. */
+#define PB_STATUS_UNKNOWN BIT(8)
+#define PB_STATUS_OTHER BIT(9)
+#define PB_STATUS_FANS BIT(10)
+#define PB_STATUS_POWER_GOOD_N BIT(11)
+#define PB_STATUS_WORD_MFR BIT(12)
+#define PB_STATUS_INPUT BIT(13)
+#define PB_STATUS_IOUT_POUT BIT(14)
+#define PB_STATUS_VOUT BIT(15)
+
+/* STATUS_VOUT (PMBus 1.3.1 Part II sec 17.3, Table 17). */
+#define PB_VOLTAGE_VOUT_MAX_MIN_WARN BIT(3)
+#define PB_VOLTAGE_UV_FAULT BIT(4)
+#define PB_VOLTAGE_UV_WARNING BIT(5)
+#define PB_VOLTAGE_OV_WARNING BIT(6)
+#define PB_VOLTAGE_OV_FAULT BIT(7)
+
+/* STATUS_IOUT (Part II sec 10.6). */
+#define PB_POUT_OP_WARNING BIT(0)
+#define PB_POUT_OP_FAULT BIT(1)
+#define PB_POWER_LIMITING BIT(2)
+#define PB_CURRENT_SHARE_FAULT BIT(3)
+#define PB_IOUT_UC_FAULT BIT(4)
+#define PB_IOUT_OC_WARNING BIT(5)
+#define PB_IOUT_OC_LV_FAULT BIT(6)
+#define PB_IOUT_OC_FAULT BIT(7)
+
+/* STATUS_INPUT (Part II sec 10.7). */
+#define PB_PIN_OP_WARNING BIT(0)
+#define PB_IIN_OC_WARNING BIT(1)
+#define PB_IIN_OC_FAULT BIT(2)
+
+/* STATUS_TEMPERATURE (Part II sec 10.8). */
+#define PB_TEMP_UT_FAULT BIT(4)
+#define PB_TEMP_UT_WARNING BIT(5)
+#define PB_TEMP_OT_WARNING BIT(6)
+#define PB_TEMP_OT_FAULT BIT(7)
+
+/* STATUS_CML (Part II sec 10.9). */
+#define PB_CML_FAULT_OTHER_MEM_LOGIC BIT(0)
+#define PB_CML_FAULT_OTHER_COMM BIT(1)
+#define PB_CML_FAULT_PROCESSOR BIT(3)
+#define PB_CML_FAULT_MEMORY BIT(4)
+#define PB_CML_FAULT_PACKET_ERROR BIT(5)
+#define PB_CML_FAULT_INVALID_DATA BIT(6)
+#define PB_CML_FAULT_INVALID_COMMAND BIT(7)
+
+/*
+ * OPERATION (01h) command bits per PMBus 1.3 Part II sec 9.1. Bit[7]
+ * is the master rail enable; the lower bits select margin high/low
+ * and turn off behaviour (subset surfaced for the regulator helper).
+ */
+#define PB_OPERATION_ON BIT(7)
+
+/*
+ * LINEAR11 numeric format (PMBus 1.3 Part II sec 7): 16 bit register
+ * with a signed 11 bit mantissa in bits[10:0] and a signed 5 bit
+ * exponent in bits[15:11]. Engineering value = mantissa * 2^exponent.
+ */
+#define PB_LINEAR11_MANT_MASK 0x07ff
+#define PB_LINEAR11_MANT_BITS 11
+#define PB_LINEAR11_EXP_SHIFT 11
+#define PB_LINEAR11_EXP_MASK 0x1f
+#define PB_LINEAR11_EXP_BITS 5
+
+/*
+ * Cache buffer sizes for the active device singleton + MFR_* block
+ * reads. PMBus block reads return up to 32 bytes per the SMBus spec;
+ * 16 covers every MFR string seen in practice on regulator class
+ * chips and keeps the singleton compact.
+ */
+#define PMBUS_MFR_STRING_MAX 16
+#define PMBUS_VENDOR_NAME_MAX 8
+#define PMBUS_REGULATOR_NAME_MAX 24
+
+/* PMBus revision identifiers reported by PMBUS_REVISION (98h). */
+#define PMBUS_REV_10 0x00 /* PMBus 1.0 */
+#define PMBUS_REV_11 0x11 /* PMBus 1.1 */
+#define PMBUS_REV_12 0x22 /* PMBus 1.2 */
+#define PMBUS_REV_13 0x33 /* PMBus 1.3 */
+
+/*
+ * Numeric formats and sensor classes.
+ *
+ * Mirrors linux/drivers/hwmon/pmbus/pmbus.h enum pmbus_data_format
+ * and enum pmbus_sensor_classes. A chip's pmbus_driver_info wires
+ * each sensor class to one format and (for DIRECT) to its m/b/R
+ * coefficients.
+ */
+enum pmbus_data_format {
+ pmbus_fmt_linear = 0,
+ pmbus_fmt_ieee754,
+ pmbus_fmt_direct,
+ pmbus_fmt_vid,
+};
+
+enum pmbus_sensor_classes {
+ PSC_VOLTAGE_IN = 0,
+ PSC_VOLTAGE_OUT,
+ PSC_CURRENT_IN,
+ PSC_CURRENT_OUT,
+ PSC_POWER,
+ PSC_TEMPERATURE,
+ PSC_NUM_CLASSES
+};
+
+/*
+ * Per chip identification record. Each per chip driver declares one
+ * of these and points the framework at it. Subset of the kernel
+ * struct pmbus_driver_info: U-Boot has no per page caches, no fan
+ * accessors, no virtual registers, no async sysfs publication.
+ *
+ * pages number of PAGE distinct rails the chip exposes
+ * (1 for single rail parts).
+ * format[] numeric format per sensor class.
+ * m/b/R[] DIRECT format coefficients per sensor class. See
+ * pmbus_reg2data_direct() below for the formula.
+ * Unused for non DIRECT classes.
+ * read_byte_data, read_word_data
+ * optional per chip register translators. Return the
+ * standard register value on success, ENODATA to fall
+ * through to the generic transport, any other negative
+ * errno on bus error.
+ * identify optional probe time hook to discover format and
+ * page count from the chip itself (for example, the
+ * MPQ8785 VOUT_MODE switch between LINEAR and DIRECT).
+ */
+struct pmbus_driver_info {
+ int pages;
+ enum pmbus_data_format format[PSC_NUM_CLASSES];
+ int m[PSC_NUM_CLASSES];
+ int b[PSC_NUM_CLASSES];
+ int R[PSC_NUM_CLASSES];
+
+ int (*read_byte_data)(struct udevice *dev, int page, int reg);
+ int (*read_word_data)(struct udevice *dev, int page, int reg);
+ int (*identify)(struct udevice *dev, struct pmbus_driver_info *info);
+
+ /*
+ * Optional sparse table of chip specific STATUS_* bit name
+ * substitutions. Terminated by an entry with .name = NULL
+ * (matching the convention used by struct udevice_id and
+ * other U-Boot driver tables). NULL pointer means the chip
+ * uses only PMBus 1.x standard names. See struct
+ * pmbus_status_override and pmbus_print_status_bits().
+ */
+ const struct pmbus_status_override *status_overrides;
+
+ /*
+ * Bitmask (BIT(enum pmbus_sensor_classes)) of the sensor classes
+ * this chip actually implements. When non-zero, pmbus_print_telemetry
+ * prints exactly these classes -- mirroring the kernel's per chip
+ * sensor set -- and skips the rest. This is how an MPS buck that
+ * ACKs READ_POUT / READ_IIN with an uncalibrated value still hides
+ * POWER / CURRENT_IN (the kernel's mpq8646 driver exposes neither).
+ * Zero means "not declared": the telemetry printer falls back to a
+ * live pmbus_word_command_supported() probe per class, which is what
+ * the generic driver (compatible = "pmbus") relies on.
+ */
+ u8 classes_present;
+};
+
+/*
+ * Decoder helpers (raw register, returns engineering value in micro
+ * units).
+ *
+ * All return signed micro units (uV, uA, udegC), 64 bit to avoid
+ * overflow on large mantissa times exponent products. The caller
+ * divides by 1000 for milli units, or by 1_000_000 for the integer
+ * engineering value.
+ */
+
+/*
+ * LINEAR11. Bits[15:11] = signed 5 bit exponent Y, bits[10:0] =
+ * signed 11 bit mantissa N. Engineering value = N * 2^Y.
+ *
+ * Used by most PMBus chips for VIN, IIN, IOUT, TEMP. Some MPS
+ * parts deviate (they report DIRECT format with chip specific m/b/R
+ * coefficients); check the chip datasheet against PMBUS_VOUT_MODE
+ * and the Linux per chip driver if porting.
+ */
+s64 pmbus_reg2data_linear11(u16 raw);
+
+/*
+ * LINEAR16. 16 bit unsigned mantissa multiplied by 2^Y, where Y is
+ * the signed 5 bit exponent supplied via VOUT_MODE bits[4:0]. The
+ * caller must read VOUT_MODE (cmd 0x20) and pass it in vout_mode.
+ * Only the mode_mask bits[7:5] = 0 selector is the LINEAR16 path.
+ *
+ * Used for READ_VOUT (8Bh) on chips whose VOUT_MODE selects Linear.
+ * Returns 0 if VOUT_MODE indicates a non Linear mode; the caller
+ * is then expected to dispatch to pmbus_reg2data_direct() with the
+ * appropriate per chip m/b/R, or to pmbus_reg2data_vid() / _ieee754()
+ * if the chip uses those formats.
+ */
+s64 pmbus_reg2data_linear16(u16 raw, u8 vout_mode);
+
+/*
+ * DIRECT. PMBus 1.3 Part II sec 8.4. The chip stores a signed 16 bit
+ * value X; the engineering value Y is one over m, multiplied by the
+ * quantity (X scaled by ten to the power minus R, then offset by
+ * minus b), with chip specific (m, b, R) coefficients.
+ *
+ * In symbolic form: Y = (1/m) * (X * 10**(-R) - b). The negative
+ * exponent and trailing subtraction are math operators in the
+ * formula, not punctuation in the prose.
+ *
+ * Returns micro units. Implementation order matches the Linux
+ * reference (multiply before subtract, scale R then divide by m) to
+ * minimise quantisation drift. m == 0 returns 0.
+ */
+s64 pmbus_reg2data_direct(s16 raw, int m, int b, int R);
+
+/*
+ * Encoder: engineering value (micro units) to LINEAR16 raw register
+ * value. Used by pre kernel rail trim code (see board/nxp/common/vid.c)
+ * to write VOUT_COMMAND from a target voltage. The exponent is
+ * recovered from VOUT_MODE.
+ *
+ * Returns 0 if VOUT_MODE indicates a non Linear format; the caller
+ * must then dispatch to pmbus_data2reg_direct() (DIRECT format) or
+ * the VID / IEEE754 encoders (when those land) per the chip's actual
+ * VOUT_MODE selector.
+ */
+u16 pmbus_data2reg_linear16(s64 micro, u8 vout_mode);
+
+/*
+ * Encoder: engineering value (micro units) to DIRECT raw register
+ * value. Inverse of pmbus_reg2data_direct():
+ *
+ * X = (m * Y + b) * 10^R
+ *
+ * with chip specific (m, b, R) coefficients (typically taken from
+ * the chip's pmbus_driver_info[PSC_VOLTAGE_OUT]). m == 0 returns 0.
+ *
+ * The result is saturated to the s16 range mandated by the PMBus
+ * 1.3 Part II sec 8.4 DIRECT encoding; out of range targets return
+ * 0x7fff or 0x8000 rather than wrapping.
+ */
+u16 pmbus_data2reg_direct(s64 micro, int m, int b, int R);
+
+/*
+ * Dispatcher: pick the right reg2data_* helper based on the chip's
+ * pmbus_driver_info[class]. vout_mode is consulted only for
+ * VOLTAGE_OUT in linear format. For DIRECT, m/b/R are taken from
+ * info. For VID and IEEE754 the dispatcher returns 0 (formats
+ * not yet wired up; add when a consumer lands).
+ */
+s64 pmbus_reg2data(const struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes class,
+ u16 raw, u8 vout_mode);
+
+/*
+ * Transport helpers.
+ *
+ * Thin wrappers over the U-Boot DM I2C primitives that handle PMBus
+ * framing details (little endian word layout, two stage block read,
+ * CLEAR_FAULTS pseudo command without payload).
+ */
+
+/* Read a byte register. */
+int pmbus_read_byte(struct udevice *dev, u8 cmd, u8 *val);
+
+/* Read a 16 bit register, little endian on the wire. */
+int pmbus_read_word(struct udevice *dev, u8 cmd, u16 *val);
+
+/* Write a byte register. */
+int pmbus_write_byte(struct udevice *dev, u8 cmd, u8 val);
+
+/* Write a 16 bit register, little endian on the wire. */
+int pmbus_write_word(struct udevice *dev, u8 cmd, u16 val);
+
+/*
+ * Block read of a vendor string register (MFR_ID, MFR_MODEL,
+ * MFR_REVISION). The first wire byte is the payload length; the
+ * helper does the second read for the payload itself, so even strict
+ * I2C controllers (which forbid over read on block transactions)
+ * work. Output is null terminated and printable only (non printable
+ * bytes are substituted with '.').
+ *
+ * reverse_bytes: some MPS NVM personalities store ASCII strings
+ * LSB first (chip returns "SPM" for the human string "MPS"); pass
+ * true to reverse on copy. Spec compliant chips pass false.
+ *
+ * Returns string length on success or a negative errno on bus error
+ * or invalid length byte. outsz must be at least 2.
+ */
+int pmbus_read_string(struct udevice *dev, u8 cmd, char *out, int outsz,
+ bool reverse_bytes);
+
+/* Issue a CLEAR_FAULTS (03h) write. Clears RAM sticky STATUS_*. */
+int pmbus_clear_faults(struct udevice *dev);
+
+/*
+ * Capability probe: is a word sized command implemented by the chip?
+ *
+ * Primary signal is the bus NAK -- compliant parts do not ACK a
+ * command they do not implement, so the word read fails. Secondary
+ * signal is a clean -> dirty transition of STATUS_CML[INVALID_COMMAND]
+ * across the read (a chip that ACKs but does not implement the
+ * register raises it). Non destructive: never issues CLEAR_FAULTS, so
+ * sticky fault history survives for a subsequent pmbus status; a
+ * pre existing CML fault disables the secondary signal so it cannot
+ * produce a false "unsupported".
+ *
+ * Returns true if the command appears supported, false otherwise.
+ */
+bool pmbus_word_command_supported(struct udevice *dev, u8 reg);
+
+/*
+ * High level snapshot printers shared by the pmbus CLI and board
+ * boot time diagnostics. Both operate on the current pmbus_active()
+ * device (select it first via pmbus_set_active()); chip is the I2C
+ * handle from pmbus_active_get_i2c() / the CLI's require_active().
+ *
+ * pmbus_print_telemetry: decodes VIN / VOUT / IIN / IOUT / POUT / TEMP
+ * through the active device's pmbus_driver_info (LINEAR / DIRECT / VID
+ * per VOUT_MODE and per class format), skipping commands the chip does
+ * not implement (pmbus_word_command_supported). Falls back to
+ * LINEAR16 / LINEAR11 when no driver_info is cached. Caller prints the
+ * header line.
+ *
+ * pmbus_print_status_word: reads + decodes STATUS_WORD with the active
+ * device's chip specific status_overrides, if any.
+ */
+void pmbus_print_telemetry(struct udevice *chip);
+void pmbus_print_status_word(struct udevice *chip);
+
+/*
+ * Status bit name decoding.
+ *
+ * Sparse mask to name table. pmbus_print_bits() emits only the bits
+ * that are SET in v, joined by |; if no bit is set, prints
+ * clean. Bits not in the table are silently ignored (RESERVED bits
+ * or chip specific bits handled by a separate per chip table).
+ */
+struct pmbus_bit {
+ u16 mask;
+ const char *name;
+};
+
+void pmbus_print_bits(u16 v, const struct pmbus_bit *tab);
+
+/*
+ * Per chip override entry. When a chip reuses a PMBus standard
+ * STATUS bit for a documented chip specific signal (for example MPS
+ * uses STATUS_WORD bit[12] = MFR_SPECIFIC as NVM_SUMMARY, bit[8] =
+ * UNKNOWN as WATCH_DOG, bit[0] = NONE_ABOVE as DRMOS_FAULT), the
+ * per chip driver supplies a sparse table of (reg, mask, name)
+ * triples and pmbus_print_status_bits() substitutes the chip name
+ * for the standard one when the bit is set.
+ *
+ * reg is one of PMBUS_STATUS_WORD / VOUT / IOUT / INPUT /
+ * TEMPERATURE / CML, so the same table can carry overrides for
+ * every status register on the chip in one place. Tables that omit
+ * a (reg, mask) leave the standard name in place.
+ *
+ * Override entries whose mask is NOT in the standard table are
+ * still printed (the chip can extend coverage beyond PMBus 1.x for
+ * vendor specific bits in standard registers).
+ *
+ * Tables are NULL terminated: the last entry has .name = NULL.
+ * Following the same convention U-Boot uses for struct udevice_id
+ * and other driver tables avoids the explicit-count foot-gun.
+ */
+struct pmbus_status_override {
+ u8 reg;
+ u16 mask;
+ const char *name;
+};
+
+/*
+ * Print the bit names of a STATUS_* register value. For each bit
+ * set in v, prefer a chip override matching (reg, mask) over the
+ * standard std table entry; if neither matches, the bit is
+ * silently skipped (RESERVED). If no bit is set at all, prints
+ * clean. Pass ovr = NULL to disable the override path.
+ */
+void pmbus_print_status_bits(u8 reg, u16 v,
+ const struct pmbus_bit *std,
+ const struct pmbus_status_override *ovr);
+
+/*
+ * Built in PMBus 1.3 standard bit tables (use these from per chip
+ * drivers and board diagnostics; vendor extensions go in chip local
+ * tables that the per chip driver passes alongside these).
+ */
+/*
+ * All tables below are NULL terminated (last entry has .name = NULL),
+ * so callers walk with for (t = tab; t && t->name; t++) and the
+ * helpers above need no count argument.
+ */
+extern const struct pmbus_bit pmbus_status_word_bits[];
+extern const struct pmbus_bit pmbus_status_vout_bits[];
+extern const struct pmbus_bit pmbus_status_iout_bits[];
+extern const struct pmbus_bit pmbus_status_input_bits[];
+extern const struct pmbus_bit pmbus_status_temp_bits[];
+extern const struct pmbus_bit pmbus_status_cml_bits[];
+
+/*
+ * Active device tracking for the pmbus U-Boot CLI.
+ *
+ * The framework keeps one active PMBus device. It is selected by
+ * pmbus dev <bus>:<addr> (raw I2C tuple) and remembered across
+ * subcommands so subsequent invocations of pmbus telemetry,
+ * pmbus status, pmbus dump, etc. operate on the same chip
+ * without re-typing the address.
+ *
+ * pmbus_set_active() probes the chip's MFR_ID at the given address,
+ * looks the result up in the chip-match registry (populated by
+ * per chip drivers via pmbus_register_chip()), and caches the
+ * resulting struct pmbus_driver_info. Subcommands consult
+ * pmbus_active() to find the cached metadata.
+ */
+struct pmbus_active_dev {
+ bool valid;
+ int bus_seq;
+ u8 addr;
+ char vendor[PMBUS_VENDOR_NAME_MAX];
+ char name[PMBUS_REGULATOR_NAME_MAX]; /* DT regulator-name when bound; "" otherwise */
+ char mfr_id[PMBUS_MFR_STRING_MAX];
+ char mfr_model[PMBUS_MFR_STRING_MAX];
+ char mfr_revision[PMBUS_MFR_STRING_MAX];
+ const struct pmbus_driver_info *info;
+};
+
+const struct pmbus_active_dev *pmbus_active(void);
+int pmbus_active_get_i2c(struct udevice **i2c_dev);
+int pmbus_set_active(int bus_seq, u8 addr);
+void pmbus_clear_active(void);
+
+/*
+ * Per chip driver / board file registers a chip match so the
+ * framework can associate an MFR_ID prefix (read at probe time)
+ * with a vendor namespace ("mps", "lltc", "renesas", ...) and a
+ * pmbus_driver_info pointer. The first matching entry wins.
+ *
+ * mfr_id_reverse flags MPS style chips that store the MFR_ID
+ * string LSB first (chip returns "SPM" for the human string
+ * "MPS"); the framework reads the string in both orderings and
+ * matches against the prefix in the natural reading.
+ */
+struct pmbus_chip_match {
+ const char *mfr_id;
+ bool mfr_id_reverse;
+ const char *vendor;
+ const struct pmbus_driver_info *info;
+};
+
+int pmbus_register_chip(const struct pmbus_chip_match *match);
+
+/*
+ * Resolve a regulator-name (DT regulator-name property) to its
+ * (bus, addr) tuple by walking UCLASS_REGULATOR. Used by the
+ * pmbus dev <name> CLI alias so a chip bound through DT can be
+ * selected by its human readable rail name (e.g. "+0V8_VDD")
+ * instead of the i2c bus / address pair. Returns 0 on success
+ * (out parameters populated and the regulator probed), or a
+ * negative errno if no match is found or the bus / address cannot
+ * be derived. Available only when CONFIG_DM_REGULATOR is set.
+ */
+int pmbus_resolve_by_name(const char *name, int *bus_seq, u8 *addr);
+
+/*
+ * Vendor extension dispatcher.
+ *
+ * When the user types pmbus <vendor> <args...>, the framework
+ * looks up the registered handler for <vendor> and calls it with
+ * the argv tail (argv[0] = "<vendor>"). The handler operates on
+ * pmbus_active(), or returns CMD_RET_USAGE if the active device is
+ * not from this vendor.
+ *
+ * Per chip drivers register their vendor handler at init time. The
+ * MPS extension publishes pmbus mps last, pmbus mps clear last,
+ * and pmbus mps clear force.
+ */
+typedef int (*pmbus_vendor_handler_t)(struct cmd_tbl *cmdtp, int flag,
+ int argc, char *const argv[]);
+
+struct pmbus_vendor_op {
+ const char *vendor;
+ pmbus_vendor_handler_t handler;
+ const char *help;
+};
+
+int pmbus_register_vendor_handler(const struct pmbus_vendor_op *op);
+const struct pmbus_vendor_op *pmbus_lookup_vendor(const char *vendor);
+unsigned int pmbus_vendor_count(void);
+const struct pmbus_vendor_op *pmbus_vendor_at(unsigned int i);
+
+#endif /* _PMBUS_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index 9e0f0ad7d06..24e55ade4d3 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -283,6 +283,22 @@ config PANIC_HANG
development since you can try to debug the conditions that lead to
the situation.
+config PMBUS
+ bool "PMBus 1.x decoder and transport helpers"
+ depends on DM_I2C
+ help
+ Enable include/pmbus.h and lib/pmbus.c: standard PMBus 1.x
+ command codes, LINEAR11, LINEAR16, and DIRECT numeric format
+ decoders, the two stage SMBus block read helper used for
+ MFR_ID, MFR_MODEL, and MFR_REVISION reads, and the table
+ driven STATUS_* bit print helper.
+
+ This is the substrate for any pre kernel PMBus consumer in
+ U-Boot (board/nxp/common/vid.c rail trim, board local telemetry
+ diagnostics, future per chip regulator drivers under
+ drivers/power/regulator/). It is not a hwmon clone. See
+ doc/develop/pmbus.rst for the policy notes.
+
config REGEX
bool "Enable regular expression support"
default y if NET_LEGACY
diff --git a/lib/Makefile b/lib/Makefile
index d0ffabc2b47..222378a8531 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -53,6 +53,7 @@ obj-y += rc4.o
obj-$(CONFIG_RBTREE) += rbtree.o
obj-$(CONFIG_BITREVERSE) += bitrev.o
obj-y += list_sort.o
+obj-$(CONFIG_PMBUS) += pmbus.o
endif
obj-$(CONFIG_$(PHASE_)TPM) += tpm-common.o
diff --git a/lib/pmbus.c b/lib/pmbus.c
new file mode 100644
index 00000000000..d49576ad3bd
--- /dev/null
+++ b/lib/pmbus.c
@@ -0,0 +1,859 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * PMBus 1.x decoders, transport helpers, and standard status bit
+ * tables for U-Boot. See include/pmbus.h for the API surface and
+ * doc/develop/pmbus.rst for the porting guide.
+ *
+ * Decoder math is implemented from the PMBus 1.3 specification:
+ * 1. Part I (transport): see
+ * doc/PMBus/PMBus_Specification_Rev_1_3_1_Part_I_20150313.{pdf,txt}
+ * 2. Part II (commands): see
+ * doc/PMBus/PMBus_Specification_Rev_1_3_1_Part_II_20150313.{pdf,txt}
+ *
+ * Reference Linux implementation: linux/drivers/hwmon/pmbus/pmbus_core.c
+ * (the kernel side `struct pmbus_data` caching and hwmon publication
+ * layers do not apply; only the arithmetic carries over).
+ *
+ * No code in this file may reference a specific board, SoC, or
+ * product. Per chip quirks (MPS DIRECT format LSBs, vendor registers,
+ * VID coercion, ADDR_VBOOT auto promotion, and the like) belong in
+ * per chip drivers under drivers/power/regulator/ or in board local
+ * files under board/<vendor>/<board>/.
+ */
+
+#include <ctype.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <limits.h>
+#include <linux/bitops.h>
+#include <power/regulator.h>
+
+static int pmbus_sign_extend(unsigned int v, unsigned int width)
+{
+ unsigned int mask = (1U << width) - 1U;
+ unsigned int sign = 1U << (width - 1U);
+
+ v &= mask;
+ if (v & sign)
+ v |= ~mask;
+ return (int)v;
+}
+
+s64 pmbus_reg2data_linear11(u16 raw)
+{
+ int mantissa = pmbus_sign_extend(raw & PB_LINEAR11_MANT_MASK,
+ PB_LINEAR11_MANT_BITS);
+ int exponent = pmbus_sign_extend((raw >> PB_LINEAR11_EXP_SHIFT) &
+ PB_LINEAR11_EXP_MASK,
+ PB_LINEAR11_EXP_BITS);
+ s64 micro;
+
+ /* Engineering value = mantissa * 2^exponent, scaled to micro units. */
+ micro = (s64)mantissa * 1000000LL;
+ if (exponent >= 0)
+ micro <<= exponent;
+ else
+ micro >>= -exponent;
+ return micro;
+}
+
+s64 pmbus_reg2data_linear16(u16 raw, u8 vout_mode)
+{
+ int exponent;
+ s64 micro;
+
+ /*
+ * VOUT_MODE bits[7:5] = mode; bits[4:0] = parameter. Linear mode
+ * (000) treats bits[4:0] as the signed 5-bit exponent. For other
+ * modes the caller must dispatch elsewhere.
+ */
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) != PB_VOUT_MODE_LINEAR)
+ return 0;
+
+ exponent = pmbus_sign_extend(vout_mode & PB_VOUT_MODE_PARAM_MASK, 5);
+
+ /* Mantissa is unsigned 16-bit; scale to micro units. */
+ micro = (s64)raw * 1000000LL;
+ if (exponent >= 0)
+ micro <<= exponent;
+ else
+ micro >>= -exponent;
+ return micro;
+}
+
+s64 pmbus_reg2data_direct(s16 raw, int m, int b, int R)
+{
+ s64 acc;
+
+ if (m == 0)
+ return 0;
+
+ /*
+ * PMBus Part II sec 8.4: Y = (1/m) * (X * 10^-R - b)
+ *
+ * Pre scale acc to micro units so the final integer division by
+ * m absorbs the rounding loss into the least significant micro
+ * digit rather than into a coarser place.
+ */
+ acc = (s64)raw * 1000000LL;
+
+ /* Apply 10^-R: positive R means divide; negative R means multiply. */
+ while (R > 0) {
+ acc /= 10;
+ R--;
+ }
+ while (R < 0) {
+ acc *= 10;
+ R++;
+ }
+
+ /* Subtract the offset b, also in micro units. */
+ acc -= (s64)b * 1000000LL;
+
+ /* Final: divide by m. */
+ acc /= m;
+ return acc;
+}
+
+u16 pmbus_data2reg_linear16(s64 micro, u8 vout_mode)
+{
+ int exponent;
+ s64 raw;
+
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) != PB_VOUT_MODE_LINEAR)
+ return 0;
+
+ exponent = pmbus_sign_extend(vout_mode & PB_VOUT_MODE_PARAM_MASK, 5);
+
+ /* raw = micro / (2^exponent * 10^6). */
+ raw = micro;
+ if (exponent >= 0)
+ raw >>= exponent;
+ else
+ raw <<= -exponent;
+ raw /= 1000000LL;
+
+ if (raw < 0)
+ raw = 0;
+ if (raw > U16_MAX)
+ raw = U16_MAX;
+ return (u16)raw;
+}
+
+u16 pmbus_data2reg_direct(s64 micro, int m, int b, int R)
+{
+ s64 acc;
+
+ if (m == 0)
+ return 0;
+
+ /*
+ * Inverse of pmbus_reg2data_direct(): X = (m * Y + b) * 10^R.
+ * Work in micro units throughout: acc = m * Y_micro + b * 10^6,
+ * then scale by 10^R, finally divide by 10^6 to get the raw
+ * chip count. Order chosen to match the decoder's quantisation
+ * pattern so a round trip (data2reg then reg2data) returns the
+ * input within +/- one LSB.
+ */
+ acc = (s64)m * micro + (s64)b * 1000000LL;
+
+ while (R > 0) {
+ acc *= 10;
+ R--;
+ }
+ while (R < 0) {
+ acc /= 10;
+ R++;
+ }
+
+ acc /= 1000000LL;
+
+ /* PMBus 1.3 Part II sec 8.4 mandates a signed 16 bit raw value. */
+ if (acc > S16_MAX)
+ acc = S16_MAX;
+ if (acc < S16_MIN)
+ acc = S16_MIN;
+ return (u16)(s16)acc;
+}
+
+s64 pmbus_reg2data(const struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes class,
+ u16 raw, u8 vout_mode)
+{
+ if (!info || class >= PSC_NUM_CLASSES)
+ return 0;
+
+ switch (info->format[class]) {
+ case pmbus_fmt_linear:
+ if (class == PSC_VOLTAGE_OUT)
+ return pmbus_reg2data_linear16(raw, vout_mode);
+ return pmbus_reg2data_linear11(raw);
+
+ case pmbus_fmt_direct:
+ return pmbus_reg2data_direct((s16)raw,
+ info->m[class],
+ info->b[class],
+ info->R[class]);
+
+ case pmbus_fmt_vid:
+ case pmbus_fmt_ieee754:
+ /*
+ * Not yet wired up. Add when a consumer lands. VID needs
+ * the per page vrm_version table from the kernel's
+ * pmbus_reg2data_vid(); IEEE754 needs the half precision
+ * decoder from pmbus_reg2data_ieee754().
+ */
+ return 0;
+ }
+
+ return 0;
+}
+
+int pmbus_read_byte(struct udevice *dev, u8 cmd, u8 *val)
+{
+ return dm_i2c_read(dev, cmd, val, 1);
+}
+
+int pmbus_read_word(struct udevice *dev, u8 cmd, u16 *val)
+{
+ u8 raw[2];
+ int ret;
+
+ ret = dm_i2c_read(dev, cmd, raw, 2);
+ if (ret)
+ return ret;
+ *val = (u16)raw[0] | ((u16)raw[1] << 8);
+ return 0;
+}
+
+int pmbus_write_byte(struct udevice *dev, u8 cmd, u8 val)
+{
+ return dm_i2c_write(dev, cmd, &val, 1);
+}
+
+int pmbus_write_word(struct udevice *dev, u8 cmd, u16 val)
+{
+ u8 raw[2];
+
+ raw[0] = (u8)(val & 0xff); /* PMBus words are little-endian */
+ raw[1] = (u8)(val >> 8);
+ return dm_i2c_write(dev, cmd, raw, 2);
+}
+
+int pmbus_read_string(struct udevice *dev, u8 cmd, char *out, int outsz,
+ bool reverse_bytes)
+{
+ u8 raw[PMBUS_MFR_STRING_MAX];
+ int ret, len, i;
+
+ if (outsz < 2)
+ return -EINVAL;
+
+ /* Stage 1: read the length byte. */
+ ret = dm_i2c_read(dev, cmd, raw, 1);
+ if (ret)
+ return ret;
+
+ len = raw[0];
+ if (len <= 0 || len > (int)sizeof(raw))
+ return -EBADMSG;
+ if (len > outsz - 1)
+ len = outsz - 1;
+
+ /* Stage 2: reread length + payload (some controllers mandate this). */
+ ret = dm_i2c_read(dev, cmd, raw, len + 1);
+ if (ret)
+ return ret;
+
+ if (reverse_bytes) {
+ for (i = 0; i < len; i++) {
+ u8 b = raw[len - i];
+
+ out[i] = isprint(b) ? (char)b : '.';
+ }
+ } else {
+ for (i = 0; i < len; i++) {
+ u8 b = raw[i + 1];
+
+ out[i] = isprint(b) ? (char)b : '.';
+ }
+ }
+ out[len] = '\0';
+ return len;
+}
+
+int pmbus_clear_faults(struct udevice *dev)
+{
+ return dm_i2c_write(dev, PMBUS_CLEAR_FAULTS, NULL, 0);
+}
+
+void pmbus_print_bits(u16 v, const struct pmbus_bit *tab)
+{
+ const struct pmbus_bit *t;
+ int first = 1;
+
+ if (v == 0) {
+ printf("clean");
+ return;
+ }
+ for (t = tab; t && t->name; t++) {
+ if (v & t->mask) {
+ printf("%s%s", first ? "" : "|", t->name);
+ first = 0;
+ }
+ }
+}
+
+void pmbus_print_status_bits(u8 reg, u16 v,
+ const struct pmbus_bit *std,
+ const struct pmbus_status_override *ovr)
+{
+ const struct pmbus_bit *s;
+ const struct pmbus_status_override *o;
+ int first = 1;
+
+ if (v == 0) {
+ printf("clean");
+ return;
+ }
+
+ /*
+ * Pass 1: walk the standard table in declared order so the
+ * printout retains the conventional bit-15-first ordering. For
+ * each set bit, prefer a chip override matching (reg, mask).
+ */
+ for (s = std; s && s->name; s++) {
+ const char *name;
+
+ if (!(v & s->mask))
+ continue;
+ name = s->name;
+ for (o = ovr; o && o->name; o++) {
+ if (o->reg == reg && o->mask == s->mask) {
+ name = o->name;
+ break;
+ }
+ }
+ printf("%s%s", first ? "" : "|", name);
+ first = 0;
+ }
+
+ /*
+ * Pass 2: print overrides whose mask is not in the standard
+ * table at all (chip-specific bit at a position the spec
+ * leaves RESERVED). These would otherwise be swallowed.
+ */
+ for (o = ovr; o && o->name; o++) {
+ bool in_std = false;
+
+ if (o->reg != reg)
+ continue;
+ if (!(v & o->mask))
+ continue;
+ for (s = std; s && s->name; s++) {
+ if (s->mask == o->mask) {
+ in_std = true;
+ break;
+ }
+ }
+ if (in_std)
+ continue;
+ printf("%s%s", first ? "" : "|", o->name);
+ first = 0;
+ }
+}
+
+/*
+ * Standard PMBus 1.3 status bit tables. Per-chip drivers may publish
+ * their own tables for vendor extended bits (e.g. NVM summary bits,
+ * DR MOS faults) but the standard layout below is the safe baseline.
+ *
+ * All tables are NULL terminated (`name = NULL` sentinel), matching
+ * the convention used elsewhere in U-Boot for driver tables.
+ */
+const struct pmbus_bit pmbus_status_word_bits[] = {
+ { PB_STATUS_VOUT, "VOUT" },
+ { PB_STATUS_IOUT_POUT, "IOUT_POUT" },
+ { PB_STATUS_INPUT, "INPUT" },
+ { PB_STATUS_WORD_MFR, "MFR" },
+ { PB_STATUS_POWER_GOOD_N, "PG#" },
+ { PB_STATUS_FANS, "FANS" },
+ { PB_STATUS_OTHER, "OTHER" },
+ { PB_STATUS_UNKNOWN, "UNKNOWN" },
+ { PB_STATUS_BUSY, "BUSY" },
+ { PB_STATUS_OFF, "OFF" },
+ { PB_STATUS_VOUT_OV, "VOUT_OV" },
+ { PB_STATUS_IOUT_OC, "IOUT_OC" },
+ { PB_STATUS_VIN_UV, "VIN_UV" },
+ { PB_STATUS_TEMPERATURE, "TEMP" },
+ { PB_STATUS_CML, "CML" },
+ { PB_STATUS_NONE_ABOVE, "NONE_ABOVE" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_vout_bits[] = {
+ { PB_VOLTAGE_OV_FAULT, "VOUT_OV_FAULT" },
+ { PB_VOLTAGE_OV_WARNING, "VOUT_OV_WARN" },
+ { PB_VOLTAGE_UV_WARNING, "VOUT_UV_WARN" },
+ { PB_VOLTAGE_UV_FAULT, "VOUT_UV_FAULT" },
+ { PB_VOLTAGE_VOUT_MAX_MIN_WARN, "VOUT_MAX_MIN_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_iout_bits[] = {
+ { PB_IOUT_OC_FAULT, "IOUT_OC_FAULT" },
+ { PB_IOUT_OC_LV_FAULT, "IOUT_OC_LV_FAULT" },
+ { PB_IOUT_OC_WARNING, "IOUT_OC_WARN" },
+ { PB_IOUT_UC_FAULT, "IOUT_UC_FAULT" },
+ { PB_CURRENT_SHARE_FAULT, "ISHARE_FAULT" },
+ { PB_POWER_LIMITING, "POWER_LIMITING" },
+ { PB_POUT_OP_FAULT, "POUT_OP_FAULT" },
+ { PB_POUT_OP_WARNING, "POUT_OP_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_input_bits[] = {
+ { PB_IIN_OC_FAULT, "IIN_OC_FAULT" },
+ { PB_IIN_OC_WARNING, "IIN_OC_WARN" },
+ { PB_PIN_OP_WARNING, "PIN_OP_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_temp_bits[] = {
+ { PB_TEMP_OT_FAULT, "OT_FAULT" },
+ { PB_TEMP_OT_WARNING, "OT_WARN" },
+ { PB_TEMP_UT_WARNING, "UT_WARN" },
+ { PB_TEMP_UT_FAULT, "UT_FAULT" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_cml_bits[] = {
+ { PB_CML_FAULT_INVALID_COMMAND, "INVALID_CMD" },
+ { PB_CML_FAULT_INVALID_DATA, "INVALID_DATA" },
+ { PB_CML_FAULT_PACKET_ERROR, "PEC" },
+ { PB_CML_FAULT_MEMORY, "MEM" },
+ { PB_CML_FAULT_PROCESSOR, "PROC" },
+ { PB_CML_FAULT_OTHER_COMM, "OTHER_COMM" },
+ { PB_CML_FAULT_OTHER_MEM_LOGIC, "OTHER_MEM_LOGIC" },
+ { /* sentinel */ }
+};
+
+/*
+ * Active device tracking + chip / vendor registries (consumed by the
+ * `pmbus` U-Boot CLI command in cmd/pmbus.c).
+ */
+
+#define PMBUS_MAX_CHIP_MATCHES 8
+#define PMBUS_MAX_VENDOR_HANDLERS 4
+
+static struct pmbus_active_dev pmbus_active_state;
+static const struct pmbus_chip_match *pmbus_chip_table[PMBUS_MAX_CHIP_MATCHES];
+static unsigned int pmbus_chip_table_n;
+static const struct pmbus_vendor_op *pmbus_vendor_table[PMBUS_MAX_VENDOR_HANDLERS];
+static unsigned int pmbus_vendor_table_n;
+
+const struct pmbus_active_dev *pmbus_active(void)
+{
+ return pmbus_active_state.valid ? &pmbus_active_state : NULL;
+}
+
+void pmbus_clear_active(void)
+{
+ memset(&pmbus_active_state, 0, sizeof(pmbus_active_state));
+}
+
+int pmbus_active_get_i2c(struct udevice **i2c_dev)
+{
+ struct udevice *bus;
+ int ret;
+
+ if (!pmbus_active_state.valid)
+ return -ENODEV;
+ ret = uclass_get_device_by_seq(UCLASS_I2C, pmbus_active_state.bus_seq, &bus);
+ if (ret)
+ return ret;
+ return i2c_get_chip(bus, pmbus_active_state.addr, 1, i2c_dev);
+}
+
+/* engineering value in micro units -> "I.FFF<unit>" (3 fractional digits) */
+static void pmbus_emit_micro(s64 micro, const char *unit)
+{
+ s64 abs_milli = (micro < 0 ? -micro : micro) / 1000LL;
+
+ printf("%lld.%03lld%s", (long long)(micro / 1000000LL),
+ (long long)(abs_milli % 1000LL), unit);
+}
+
+struct pmbus_telem_entry {
+ u8 reg;
+ const char *label;
+ enum pmbus_sensor_classes class;
+ const char *unit;
+};
+
+/*
+ * Telemetry register set, in print order. POUT is included so PSU
+ * class parts report input/output power; chips that do not implement
+ * a given command are skipped via pmbus_word_command_supported().
+ */
+static const struct pmbus_telem_entry pmbus_telem_table[] = {
+ { PMBUS_READ_VIN, "VIN ", PSC_VOLTAGE_IN, "V" },
+ { PMBUS_READ_VOUT, "VOUT", PSC_VOLTAGE_OUT, "V" },
+ { PMBUS_READ_IIN, "IIN ", PSC_CURRENT_IN, "A" },
+ { PMBUS_READ_IOUT, "IOUT", PSC_CURRENT_OUT, "A" },
+ { PMBUS_READ_POUT, "POUT", PSC_POWER, "W" },
+ { PMBUS_READ_TEMPERATURE_1, "TEMP", PSC_TEMPERATURE, "C" },
+};
+
+bool pmbus_word_command_supported(struct udevice *dev, u8 reg)
+{
+ u8 cml_before = 0, cml_after = 0;
+ bool have_cml;
+ u16 w;
+
+ have_cml = !pmbus_read_byte(dev, PMBUS_STATUS_CML, &cml_before);
+
+ if (pmbus_read_word(dev, reg, &w))
+ return false; /* NAK: unsupported command not ACKed */
+
+ if (have_cml && !(cml_before & PB_CML_FAULT_INVALID_COMMAND) &&
+ !pmbus_read_byte(dev, PMBUS_STATUS_CML, &cml_after) &&
+ (cml_after & PB_CML_FAULT_INVALID_COMMAND))
+ return false; /* ACKed but chip raised INVALID_COMMAND */
+
+ return true;
+}
+
+/* Telemetry of the currently selected page. */
+static void pmbus_print_telemetry_page(struct udevice *chip,
+ const struct pmbus_active_dev *act)
+{
+ u8 vout_mode = 0;
+ unsigned int i;
+
+ /*
+ * On a read failure vout_mode stays 0 (LINEAR, exponent 0). That is
+ * a silent mis-scale of every VOLTAGE_OUT reading, so make the
+ * fallback visible rather than printing a wrong voltage as if good.
+ */
+ if (pmbus_read_byte(chip, PMBUS_VOUT_MODE, &vout_mode))
+ printf(" (VOUT_MODE read failed; VOUT decode assumes LINEAR exp 0)\n");
+
+ for (i = 0; i < ARRAY_SIZE(pmbus_telem_table); i++) {
+ const struct pmbus_telem_entry *e = &pmbus_telem_table[i];
+ u16 raw = 0;
+
+ /*
+ * Class gating. A chip driver that declares classes_present
+ * lists exactly the sensors it implements (kernel-style
+ * per-chip sensor set), so unlisted classes are skipped
+ * silently -- this is what hides the MPS buck's uncalibrated
+ * POUT / IIN. A generic / undeclared device instead gets a
+ * live capability probe per class.
+ */
+ if (act->info && act->info->classes_present) {
+ if (!(act->info->classes_present & BIT(e->class)))
+ continue;
+ } else if (!pmbus_word_command_supported(chip, e->reg)) {
+ printf(" %s : (not supported)\n", e->label);
+ continue;
+ }
+
+ if (pmbus_read_word(chip, e->reg, &raw)) {
+ printf(" %s : (read failed)\n", e->label);
+ continue;
+ }
+
+ printf(" %s : raw=0x%04x ", e->label, raw);
+ if (act->info) {
+ u16 dec = raw;
+
+ /*
+ * Some DIRECT format parts (e.g. MPS) report
+ * temperature as 1 degC/LSB in the low byte only;
+ * mask there. LINEAR temperatures use all 16 bits
+ * and must NOT be masked.
+ */
+ if (e->class == PSC_TEMPERATURE &&
+ act->info->format[PSC_TEMPERATURE] == pmbus_fmt_direct)
+ dec = raw & 0x00ff;
+
+ pmbus_emit_micro(pmbus_reg2data(act->info, e->class,
+ dec, vout_mode),
+ e->unit);
+ } else if (e->class == PSC_VOLTAGE_OUT) {
+ pmbus_emit_micro(pmbus_reg2data_linear16(raw, vout_mode),
+ e->unit);
+ } else {
+ pmbus_emit_micro(pmbus_reg2data_linear11(raw), e->unit);
+ printf(" (LINEAR11 fallback)");
+ }
+ printf("\n");
+ }
+}
+
+void pmbus_print_telemetry(struct udevice *chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+ int npages, p;
+ u8 zero = 0;
+
+ if (!act)
+ return;
+
+ /*
+ * Multi-rail parts (PSU bricks) expose one rail per PMBUS_PAGE.
+ * Chip drivers set pmbus_driver_info.pages; the generic driver
+ * takes it from the DT `pmbus,num-pages` (default 1). We always
+ * write PMBUS_PAGE before reading a page -- including page 0 --
+ * because a device may power up selected on a different page, which
+ * is what made the 48V PSU read all-zeros before. Only valid pages
+ * (0..npages-1) are ever written, so we never induce the
+ * out-of-range-PAGE STATUS_CML fault and the device's sticky fault
+ * log is left untouched (no CLEAR_FAULTS, no scrubbing).
+ */
+ npages = (act->info && act->info->pages > 0) ? act->info->pages : 1;
+
+ for (p = 0; p < npages; p++) {
+ u8 pg = (u8)p;
+
+ if (dm_i2c_write(chip, PMBUS_PAGE, &pg, 1)) {
+ printf(" [page %d] PAGE select failed\n", p);
+ continue;
+ }
+ if (npages > 1)
+ printf(" [page %d]\n", p);
+ pmbus_print_telemetry_page(chip, act);
+ }
+
+ if (npages > 1)
+ dm_i2c_write(chip, PMBUS_PAGE, &zero, 1); /* leave on page 0 */
+}
+
+void pmbus_print_status_word(struct udevice *chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+ const struct pmbus_status_override *ovr =
+ (act && act->info) ? act->info->status_overrides : NULL;
+ u16 word = 0;
+
+ if (pmbus_read_word(chip, PMBUS_STATUS_WORD, &word)) {
+ printf(" STATUS_WORD (79h) = (read failed)\n");
+ return;
+ }
+ printf(" STATUS_WORD (79h) = 0x%04x [", word);
+ pmbus_print_status_bits(PMBUS_STATUS_WORD, word,
+ pmbus_status_word_bits, ovr);
+ printf("]\n");
+}
+
+static const struct pmbus_chip_match *pmbus_match_mfr(const char *id)
+{
+ unsigned int i;
+
+ if (!id || !id[0])
+ return NULL;
+ for (i = 0; i < pmbus_chip_table_n; i++) {
+ const struct pmbus_chip_match *m = pmbus_chip_table[i];
+ size_t plen = strlen(m->mfr_id);
+
+ if (strlen(id) >= plen && !strncmp(id, m->mfr_id, plen))
+ return m;
+ }
+ return NULL;
+}
+
+/*
+ * Walk UCLASS_REGULATOR looking for a regulator whose I2C parent
+ * bus seq + DT reg address match the requested (bus_seq, addr).
+ * Returns the regulator-name (uclass plat .name) on hit, or NULL if
+ * no UCLASS_REGULATOR device matches (chip not bound through DT, or
+ * CONFIG_DM_REGULATOR disabled).
+ */
+static const char *pmbus_lookup_regname(int bus_seq, u8 addr)
+{
+ struct uclass *uc;
+ struct udevice *r;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR))
+ return NULL;
+
+ if (uclass_get(UCLASS_REGULATOR, &uc))
+ return NULL;
+ uclass_foreach_dev(r, uc) {
+ struct dm_regulator_uclass_plat *up;
+ struct udevice *parent = dev_get_parent(r);
+ int ra;
+
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ continue;
+ if (dev_seq(parent) != bus_seq)
+ continue;
+ ra = dev_read_addr(r);
+ if (ra < 0 || (u8)ra != addr)
+ continue;
+ up = dev_get_uclass_plat(r);
+ if (up && up->name)
+ return up->name;
+ return r->name;
+ }
+ return NULL;
+}
+
+int pmbus_set_active(int bus_seq, u8 addr)
+{
+ const struct pmbus_chip_match *match = NULL;
+ struct udevice *bus, *chip;
+ char id_fwd[PMBUS_MFR_STRING_MAX] = "";
+ char id_rev[PMBUS_MFR_STRING_MAX] = "";
+ const char *rname;
+ int ret;
+
+ pmbus_clear_active();
+
+ ret = uclass_get_device_by_seq(UCLASS_I2C, bus_seq, &bus);
+ if (ret)
+ return ret;
+ ret = i2c_get_chip(bus, addr, 1, &chip);
+ if (ret)
+ return ret;
+
+ pmbus_active_state.bus_seq = bus_seq;
+ pmbus_active_state.addr = addr;
+
+ /*
+ * Probe MFR_ID in both byte orders. Spec compliant chips return
+ * "MPS" / "TI" / etc. in the natural reading (forward); MPS NVM
+ * personalities store the string LSB first and need the reverse
+ * read. Chip table entries declare which one is canonical for
+ * the chip family they describe.
+ */
+ if (pmbus_read_string(chip, PMBUS_MFR_ID, id_fwd, sizeof(id_fwd), false) < 0)
+ id_fwd[0] = '\0';
+ if (pmbus_read_string(chip, PMBUS_MFR_ID, id_rev, sizeof(id_rev), true) < 0)
+ id_rev[0] = '\0';
+
+ match = pmbus_match_mfr(id_fwd);
+ if (match && !match->mfr_id_reverse) {
+ strlcpy(pmbus_active_state.mfr_id, id_fwd,
+ sizeof(pmbus_active_state.mfr_id));
+ } else {
+ match = pmbus_match_mfr(id_rev);
+ if (match && match->mfr_id_reverse) {
+ strlcpy(pmbus_active_state.mfr_id, id_rev,
+ sizeof(pmbus_active_state.mfr_id));
+ } else {
+ /* No registered match; cache the forward read as best effort. */
+ strlcpy(pmbus_active_state.mfr_id,
+ id_fwd[0] ? id_fwd : id_rev,
+ sizeof(pmbus_active_state.mfr_id));
+ }
+ }
+
+ if (match) {
+ pmbus_active_state.info = match->info;
+ if (match->vendor)
+ strlcpy(pmbus_active_state.vendor, match->vendor,
+ sizeof(pmbus_active_state.vendor));
+ }
+
+ /*
+ * MFR_MODEL / MFR_REVISION are best effort. Use the same byte
+ * order the matched chip declared; if nothing matched, use the
+ * forward order.
+ */
+ {
+ bool reverse = match && match->mfr_id_reverse;
+
+ pmbus_read_string(chip, PMBUS_MFR_MODEL,
+ pmbus_active_state.mfr_model,
+ sizeof(pmbus_active_state.mfr_model), reverse);
+ pmbus_read_string(chip, PMBUS_MFR_REVISION,
+ pmbus_active_state.mfr_revision,
+ sizeof(pmbus_active_state.mfr_revision), reverse);
+ }
+
+ rname = pmbus_lookup_regname(bus_seq, addr);
+ if (rname)
+ strlcpy(pmbus_active_state.name, rname,
+ sizeof(pmbus_active_state.name));
+
+ pmbus_active_state.valid = true;
+ return 0;
+}
+
+int pmbus_register_chip(const struct pmbus_chip_match *match)
+{
+ if (!match || !match->mfr_id)
+ return -EINVAL;
+ if (pmbus_chip_table_n >= PMBUS_MAX_CHIP_MATCHES)
+ return -ENOSPC;
+ pmbus_chip_table[pmbus_chip_table_n++] = match;
+ return 0;
+}
+
+int pmbus_register_vendor_handler(const struct pmbus_vendor_op *op)
+{
+ if (!op || !op->vendor || !op->handler)
+ return -EINVAL;
+ if (pmbus_vendor_table_n >= PMBUS_MAX_VENDOR_HANDLERS)
+ return -ENOSPC;
+ pmbus_vendor_table[pmbus_vendor_table_n++] = op;
+ return 0;
+}
+
+const struct pmbus_vendor_op *pmbus_lookup_vendor(const char *vendor)
+{
+ unsigned int i;
+
+ if (!vendor)
+ return NULL;
+ for (i = 0; i < pmbus_vendor_table_n; i++)
+ if (!strcmp(pmbus_vendor_table[i]->vendor, vendor))
+ return pmbus_vendor_table[i];
+ return NULL;
+}
+
+unsigned int pmbus_vendor_count(void)
+{
+ return pmbus_vendor_table_n;
+}
+
+const struct pmbus_vendor_op *pmbus_vendor_at(unsigned int i)
+{
+ return i < pmbus_vendor_table_n ? pmbus_vendor_table[i] : NULL;
+}
+
+int pmbus_resolve_by_name(const char *name, int *bus_seq, u8 *addr)
+{
+ struct udevice *reg;
+ struct udevice *parent;
+ int ret;
+ int a;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR))
+ return -ENOSYS;
+
+ if (!name || !bus_seq || !addr)
+ return -EINVAL;
+
+ ret = regulator_get_by_platname(name, ®);
+ if (ret)
+ return ret;
+
+ parent = dev_get_parent(reg);
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ return -ENODEV;
+
+ a = dev_read_addr(reg);
+ if (a < 0 || a > 0x7f)
+ return -EINVAL;
+
+ *bus_seq = dev_seq(parent);
+ *addr = (u8)a;
+ return 0;
+}
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v1 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
` (5 subsequent siblings)
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Anshul Dalal, Bo-Chen Chen, David Lechner,
Heinrich Schuchardt, Jaehoon Chung, Jerome Forissier,
Julien Masson, Kory Maincent, Kuan-Wei Chiu, Macpaul Lin,
Neil Armstrong, Peng Fan, Philip Molloy, Quentin Schulz,
Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
PMBus regulators differ in numeric formats and quirks, not in how they
are driven. Share that common behaviour as a regulator-uclass adapter
so chip drivers and the pmbus CLI do not each reimplement the decode
and transport, and add a catch-all driver on compatible = "pmbus" for
compliant chips that have no dedicated driver yet.
Gated by CONFIG_DM_REGULATOR_PMBUS_HELPER and
CONFIG_DM_REGULATOR_PMBUS_GENERIC.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 3 +
drivers/power/regulator/Kconfig | 24 ++
drivers/power/regulator/Makefile | 2 +
drivers/power/regulator/pmbus_generic.c | 90 +++++++
drivers/power/regulator/pmbus_helper.c | 315 ++++++++++++++++++++++++
drivers/power/regulator/pmbus_helper.h | 90 +++++++
include/pmbus.h | 37 +++
lib/pmbus.c | 17 ++
8 files changed, 578 insertions(+)
create mode 100644 drivers/power/regulator/pmbus_generic.c
create mode 100644 drivers/power/regulator/pmbus_helper.c
create mode 100644 drivers/power/regulator/pmbus_helper.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 01553aee45a..4cea3a82852 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1586,6 +1586,9 @@ S: Maintained
F: cmd/pmbus.c
F: doc/develop/pmbus.rst
F: doc/device-tree-bindings/regulator/pmbus.yaml
+F: drivers/power/regulator/pmbus_generic.c
+F: drivers/power/regulator/pmbus_helper.c
+F: drivers/power/regulator/pmbus_helper.h
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index ca5de5b8726..5b1a9c3f991 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -557,3 +557,27 @@ config DM_REGULATOR_MT6359
MediaTek MT6359 PMIC.
This driver supports the control of different power rails of device
through regulator interface.
+
+config DM_REGULATOR_PMBUS_HELPER
+ bool "Shared regulator helpers for PMBus chip drivers"
+ depends on DM_REGULATOR && PMBUS && DM_I2C
+ help
+ Provide shared get_value / set_value / get_enable / set_enable
+ operations for UCLASS_REGULATOR drivers that bind PMBus 1.x
+ compliant voltage regulators. Per chip drivers
+ (mps,mpq8785, lltc,ltc3882, ...) consume this helper to avoid
+ duplicating the LINEAR16 / DIRECT decoder dispatch and the
+ VOUT_MODE / VOUT_COMMAND / OPERATION transport sequences.
+
+config DM_REGULATOR_PMBUS_GENERIC
+ bool "Generic PMBus 1.x regulator driver (compatible=\"pmbus\")"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Catch all UCLASS_REGULATOR driver bound to compatible = "pmbus".
+ Auto detects the VOUT numeric format from the chip's VOUT_MODE
+ register and exposes telemetry plus voltage set / get against
+ the standard PMBus 1.x command codes. Use this for PMBus
+ compliant chips that have no per chip driver yet; promote to a
+ per chip driver only when chip specific quirks (vendor
+ registers, VID coercion, ADDR pin auto promotion, non standard
+ m / b / R coefficients) need handling.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 36a84e7cd71..b084e9ac4bc 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -49,3 +49,5 @@ obj-$(CONFIG_REGULATOR_RZG2L_USBPHY) += rzg2l-usbphy-regulator.o
obj-$(CONFIG_$(PHASE_)DM_REGULATOR_CPCAP) += cpcap_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6357) += mt6357_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
+obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
+obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
diff --git a/drivers/power/regulator/pmbus_generic.c b/drivers/power/regulator/pmbus_generic.c
new file mode 100644
index 00000000000..6ba50ce08f8
--- /dev/null
+++ b/drivers/power/regulator/pmbus_generic.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Generic PMBus 1.x compatible voltage regulator driver.
+ *
+ * Catch all driver bound to compatible = "pmbus" for chips that have
+ * no per chip driver under drivers/power/regulator/. The probe path
+ * detects the VOUT numeric format from VOUT_MODE bits[7:5]:
+ *
+ * - 0 LINEAR16 with the exponent supplied via VOUT_MODE bits[4:0]
+ * - 1 VID; mapped to pmbus_fmt_vid (decoder returns 0 today; per
+ * chip driver still required to plug a VID table)
+ * - 2 DIRECT; default coefficients m=1, b=0, R=0 (per chip
+ * coefficients arrive via PMBUS_QUERY / PMBUS_COEFFICIENTS,
+ * not yet consumed by U-Boot; values may need a per chip
+ * driver if telemetry numbers are wrong)
+ * - 3 IEEE754; mapped to pmbus_fmt_ieee754 (decoder returns 0
+ * today; per chip driver required)
+ *
+ * Other sensor classes (VIN, IIN, IOUT, TEMPERATURE) default to
+ * LINEAR which is the spec baseline for compliant chips. If an
+ * operator sees wrong telemetry numbers on this driver, the answer
+ * is to write a per chip driver with the correct format[] / m / b / R.
+ *
+ * Adapted in spirit from linux/drivers/hwmon/pmbus/pmbus.c (the
+ * kernel's generic probe driver). The U-Boot version drops the
+ * page count auto detection (most generic compliant parts are
+ * single rail; multi rail chips are quirky enough to need a per
+ * chip driver) and the kernel hwmon publication layers.
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+struct pmbus_generic_priv {
+ struct pmbus_regulator_priv base; /* must be first */
+ struct pmbus_driver_info info;
+};
+
+static int pmbus_generic_probe(struct udevice *dev)
+{
+ struct pmbus_generic_priv *gpriv = dev_get_priv(dev);
+ struct pmbus_driver_info *info = &gpriv->info;
+ enum pmbus_sensor_classes c;
+ int ret;
+
+ info->pages = 1;
+ for (c = 0; c < PSC_NUM_CLASSES; c++) {
+ info->format[c] = pmbus_fmt_linear;
+ info->m[c] = 0;
+ info->b[c] = 0;
+ info->R[c] = 0;
+ }
+
+ ret = pmbus_regulator_probe_common(dev, info, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * Avoid reading non supported pages to avoid device's sticky
+ * status.
+ */
+ info->pages = dev_read_u32_default(dev, "pmbus,num-pages", 1);
+ if (info->pages < 1)
+ info->pages = 1;
+
+ pmbus_regulator_identify_vout(gpriv->base.i2c_dev, info);
+
+ return 0;
+}
+
+static const struct udevice_id pmbus_generic_ids[] = {
+ { .compatible = "pmbus" },
+ { }
+};
+
+U_BOOT_DRIVER(pmbus_generic_regulator) = {
+ .name = "pmbus_generic_regulator",
+ .id = UCLASS_REGULATOR,
+ .of_match = pmbus_generic_ids,
+ .probe = pmbus_generic_probe,
+ .ops = &pmbus_regulator_ops,
+ .priv_auto = sizeof(struct pmbus_generic_priv),
+};
diff --git a/drivers/power/regulator/pmbus_helper.c b/drivers/power/regulator/pmbus_helper.c
new file mode 100644
index 00000000000..4763470442d
--- /dev/null
+++ b/drivers/power/regulator/pmbus_helper.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Shared UCLASS_REGULATOR operations over the PMBus 1.x framework.
+ * See pmbus_helper.h for the API surface and doc/develop/pmbus.rst
+ * for the porting guide.
+ *
+ * No code in this file may reference a specific chip family or
+ * board. Chip specific quirks (vendor registers, VID coercion,
+ * ADDR pin auto promotion, byte reversed MFR strings, etc.) belong
+ * in the per chip driver under drivers/power/regulator/<chip>.c.
+ */
+
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/types.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+static int pmbus_regulator_select_page(struct pmbus_regulator_priv *priv)
+{
+ u8 p;
+
+ if (priv->page <= 0)
+ return 0;
+ p = (u8)priv->page;
+ return dm_i2c_write(priv->i2c_dev, PMBUS_PAGE, &p, 1);
+}
+
+static int pmbus_regulator_get_value(struct udevice *dev)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 vout_mode = 0;
+ u16 raw = 0;
+ s64 uv;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ pmbus_read_byte(priv->i2c_dev, PMBUS_VOUT_MODE, &vout_mode);
+ if (pmbus_read_word(priv->i2c_dev, PMBUS_READ_VOUT, &raw))
+ return -EIO;
+
+ if (priv->info)
+ uv = pmbus_reg2data(priv->info, PSC_VOLTAGE_OUT, raw, vout_mode);
+ else
+ uv = pmbus_reg2data_linear16(raw, vout_mode);
+
+ if (uv > INT_MAX)
+ uv = INT_MAX;
+ if (uv < INT_MIN)
+ uv = INT_MIN;
+ return (int)uv;
+}
+
+static int pmbus_regulator_set_value(struct udevice *dev, int uV)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 vout_mode = 0;
+ u8 buf[2];
+ u16 raw;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_VOUT_MODE, &vout_mode))
+ return -EIO;
+
+ /*
+ * Dispatch on the chip's VOUT_MODE selector. LINEAR16 and DIRECT
+ * are wired today; VID and IEEE754 return -ENOSYS until their
+ * encoders land. For DIRECT, the m / b / R triple comes from the
+ * chip's pmbus_driver_info[PSC_VOLTAGE_OUT]; if the per chip
+ * driver did not populate them, the encoder cannot run.
+ */
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ raw = pmbus_data2reg_linear16((s64)uV, vout_mode);
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ if (!priv->info ||
+ priv->info->format[PSC_VOLTAGE_OUT] != pmbus_fmt_direct)
+ return -ENODATA;
+ raw = pmbus_data2reg_direct((s64)uV,
+ priv->info->m[PSC_VOLTAGE_OUT],
+ priv->info->b[PSC_VOLTAGE_OUT],
+ priv->info->R[PSC_VOLTAGE_OUT]);
+ break;
+ default:
+ return -ENOSYS;
+ }
+
+ buf[0] = (u8)(raw & 0xff);
+ buf[1] = (u8)((raw >> 8) & 0xff);
+ return dm_i2c_write(priv->i2c_dev, PMBUS_VOUT_COMMAND, buf, 2);
+}
+
+static int pmbus_regulator_get_enable(struct udevice *dev)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 op = 0;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_OPERATION, &op))
+ return -EIO;
+ return (op & PB_OPERATION_ON) ? 1 : 0;
+}
+
+static int pmbus_regulator_set_enable(struct udevice *dev, bool enable)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 op = 0;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_OPERATION, &op))
+ return -EIO;
+
+ if (enable)
+ op |= PB_OPERATION_ON;
+ else
+ op &= (u8)~PB_OPERATION_ON;
+ return dm_i2c_write(priv->i2c_dev, PMBUS_OPERATION, &op, 1);
+}
+
+const struct dm_regulator_ops pmbus_regulator_ops = {
+ .get_value = pmbus_regulator_get_value,
+ .set_value = pmbus_regulator_set_value,
+ .get_enable = pmbus_regulator_get_enable,
+ .set_enable = pmbus_regulator_set_enable,
+};
+
+int pmbus_regulator_read_temp(struct udevice *reg_dev, int *temp_mc)
+{
+ struct pmbus_regulator_priv *priv;
+ u16 raw = 0;
+ s64 udeg;
+ int ret;
+
+ if (!reg_dev || !temp_mc)
+ return -EINVAL;
+ priv = dev_get_priv(reg_dev);
+ if (!priv || !priv->i2c_dev)
+ return -ENODEV;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_word(priv->i2c_dev, PMBUS_READ_TEMPERATURE_1, &raw))
+ return -EIO;
+
+ /*
+ * vout_mode is meaningless for the temperature class. With a
+ * chip info record the dispatcher honours its per-class format
+ * (DIRECT m/b/R for MPS, LINEAR11 for spec-compliant parts);
+ * without one, fall back to the PMBus 1.x standard LINEAR11.
+ */
+ if (priv->info)
+ udeg = pmbus_reg2data(priv->info, PSC_TEMPERATURE, raw, 0);
+ else
+ udeg = pmbus_reg2data_linear11(raw);
+
+ *temp_mc = (int)(udeg / 1000);
+ return 0;
+}
+
+enum pmbus_data_format
+pmbus_regulator_identify_vout(struct udevice *i2c_dev,
+ struct pmbus_driver_info *info)
+{
+ u8 vout_mode = 0;
+
+ if (pmbus_read_byte(i2c_dev, PMBUS_VOUT_MODE, &vout_mode))
+ return info->format[PSC_VOLTAGE_OUT];
+
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear;
+ break;
+ case PB_VOUT_MODE_VID:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_vid;
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct;
+ info->m[PSC_VOLTAGE_OUT] = 1;
+ info->b[PSC_VOLTAGE_OUT] = 0;
+ info->R[PSC_VOLTAGE_OUT] = 0;
+ break;
+ case PB_VOUT_MODE_IEEE754:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_ieee754;
+ break;
+ default:
+ break;
+ }
+ return info->format[PSC_VOLTAGE_OUT];
+}
+
+const struct pmbus_driver_info *pmbus_regulator_info_by_addr(int bus_seq,
+ u8 addr)
+{
+ struct uclass *uc;
+ struct udevice *r;
+
+ if (uclass_get(UCLASS_REGULATOR, &uc))
+ return NULL;
+
+ uclass_foreach_dev(r, uc) {
+ struct udevice *parent = dev_get_parent(r);
+ struct pmbus_regulator_priv *priv;
+ int ra;
+
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ continue;
+ if (dev_seq(parent) != bus_seq)
+ continue;
+ ra = dev_read_addr(r);
+ if (ra < 0 || (u8)ra != addr)
+ continue;
+
+ /*
+ * Address matches. Only chips driven through this helper
+ * carry a pmbus_regulator_priv at the head of their priv;
+ * identify them by their shared ops vector so we never
+ * misread a foreign regulator's private layout.
+ */
+ if (!r->driver || r->driver->ops != &pmbus_regulator_ops)
+ return NULL;
+ if (device_probe(r))
+ return NULL;
+ priv = dev_get_priv(r);
+ return priv ? priv->info : NULL;
+ }
+ return NULL;
+}
+
+/*
+ * Spawn the generic UCLASS_THERMAL companion (drivers/thermal/
+ * pmbus_thermal.c) as a child of this regulator so READ_TEMPERATURE_1
+ * is reachable through the standard `temperature list` / `temperature
+ * get` interface. Named "<regulator-name>-temp" so several PMBus rails
+ * on one board produce distinct, descriptive device names. Failure is
+ * non-fatal: the chip still works as a UCLASS_REGULATOR.
+ */
+static void pmbus_regulator_bind_thermal(struct udevice *dev)
+{
+ struct udevice *therm;
+ const char *rname;
+ char name[48];
+
+ if (!IS_ENABLED(CONFIG_PMBUS_THERMAL))
+ return;
+ if (device_bind_driver(dev, "pmbus_thermal", "pmbus-temp", &therm))
+ return;
+ rname = dev_read_string(dev, "regulator-name");
+ snprintf(name, sizeof(name), "%s-temp", rname ? rname : dev->name);
+ device_set_name(therm, name);
+}
+
+int pmbus_regulator_probe_common(struct udevice *dev,
+ const struct pmbus_driver_info *info,
+ int page)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ int chip_addr;
+ int ret;
+
+ chip_addr = dev_read_addr(dev);
+ if (chip_addr < 0)
+ return -EINVAL;
+
+ ret = i2c_get_chip(dev_get_parent(dev), (u32)chip_addr, 1, &priv->i2c_dev);
+ if (ret)
+ return ret;
+
+ priv->info = info;
+ priv->page = page;
+
+ if (page > 0) {
+ u8 p = (u8)page;
+
+ ret = dm_i2c_write(priv->i2c_dev, PMBUS_PAGE, &p, 1);
+ if (ret)
+ return ret;
+ }
+
+ pmbus_regulator_bind_thermal(dev);
+ return 0;
+}
+
+int pmbus_regulator_apply_voltage_scale(struct udevice *dev,
+ u32 fb_divider_permille)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 buf[2];
+
+ if (fb_divider_permille == 0)
+ return 0;
+ buf[0] = (u8)(fb_divider_permille & 0xff);
+ buf[1] = (u8)((fb_divider_permille >> 8) & 0xff);
+ return dm_i2c_write(priv->i2c_dev, PMBUS_VOUT_SCALE_LOOP, buf, 2);
+}
diff --git a/drivers/power/regulator/pmbus_helper.h b/drivers/power/regulator/pmbus_helper.h
new file mode 100644
index 00000000000..82f263cd513
--- /dev/null
+++ b/drivers/power/regulator/pmbus_helper.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Shared UCLASS_REGULATOR ops for PMBus 1.x voltage regulator chips.
+ *
+ * Per chip drivers under drivers/power/regulator/<chip>.c bind a
+ * vendor,chip compatible from DT and call pmbus_regulator_probe_common()
+ * in their .probe. They install pmbus_regulator_ops as the .ops vector;
+ * the helper handles VOUT_MODE / READ_VOUT / VOUT_COMMAND / OPERATION
+ * via the tree level <pmbus.h> framework.
+ *
+ * Per chip drivers retain control of identify hooks (VOUT_MODE based
+ * format selection), chip specific quirks (vendor registers, ADDR pin
+ * auto promotion), and DT property handling (e.g. MPS
+ * mps,vout-fb-divider-ratio-permille).
+ */
+
+#ifndef _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_
+#define _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_
+
+#include <linux/types.h>
+#include <pmbus.h>
+
+struct udevice;
+struct dm_regulator_ops;
+
+/*
+ * Per chip private state. The first field of every per chip driver's
+ * priv_auto must be (or contain at offset 0) a struct
+ * pmbus_regulator_priv so the shared ops vector can recover it via
+ * dev_get_priv(dev).
+ *
+ * i2c_dev chip handle obtained from dev->parent at probe time
+ * (the parent must be a UCLASS_I2C bus).
+ * page PMBUS_PAGE selector for multi rail chips. Single rail
+ * chips set page = 0; the helper writes PMBUS_PAGE only
+ * when page > 0 to avoid wasted bus traffic on single
+ * rail parts.
+ * info pointer to the chip's pmbus_driver_info; consumed by
+ * pmbus_reg2data() / pmbus_data2reg_linear16() to pick
+ * the right format[] / m / b / R coefficients.
+ */
+struct pmbus_regulator_priv {
+ struct udevice *i2c_dev;
+ int page;
+ const struct pmbus_driver_info *info;
+};
+
+extern const struct dm_regulator_ops pmbus_regulator_ops;
+
+/*
+ * Per chip probe glue. Reads `reg` from DT, gets the I2C chip handle
+ * from dev->parent, populates priv->i2c_dev / page / info, and writes
+ * PMBUS_PAGE if page > 0. Per chip drivers call this in their .probe
+ * before any chip specific identification.
+ */
+int pmbus_regulator_probe_common(struct udevice *dev,
+ const struct pmbus_driver_info *info,
+ int page);
+
+/*
+ * Optional helper for per chip drivers that honour an external
+ * feedback divider DT property (e.g. MPS mps,vout-fb-divider-ratio-
+ * permille). Writes the supplied ratio to PMBUS_VOUT_SCALE_LOOP at
+ * probe time. fb_divider_permille == 0 leaves the chip default.
+ */
+int pmbus_regulator_apply_voltage_scale(struct udevice *dev,
+ u32 fb_divider_permille);
+
+/*
+ * Read PMBUS_VOUT_MODE and set info->format[PSC_VOLTAGE_OUT] from its
+ * mode selector bits[7:5] per PMBus 1.3 Part II sec 8.3:
+ * LINEAR -> pmbus_fmt_linear
+ * VID -> pmbus_fmt_vid
+ * DIRECT -> pmbus_fmt_direct (default coefficients m=1, b=0, R=0)
+ * IEEE754 -> pmbus_fmt_ieee754
+ *
+ * The single place that knows the VOUT_MODE bit layout; both the
+ * generic regulator and per chip drivers call it so they never
+ * re-implement the switch. Returns the selected format so a chip
+ * driver can post-adjust a quirk (e.g. MPS encodes VOUT in DIRECT
+ * with m=64 R=1 even when VOUT_MODE reports VID). On a VOUT_MODE read
+ * failure the format is left unchanged and the prior value is returned.
+ */
+enum pmbus_data_format
+pmbus_regulator_identify_vout(struct udevice *i2c_dev,
+ struct pmbus_driver_info *info);
+
+#endif /* _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_ */
diff --git a/include/pmbus.h b/include/pmbus.h
index 969108e5b53..3ac82465190 100644
--- a/include/pmbus.h
+++ b/include/pmbus.h
@@ -464,6 +464,43 @@ bool pmbus_word_command_supported(struct udevice *dev, u8 reg);
void pmbus_print_telemetry(struct udevice *chip);
void pmbus_print_status_word(struct udevice *chip);
+/*
+ * Regulator -> thermal bridge.
+ *
+ * Read READ_TEMPERATURE_1 (8Dh) from a UCLASS_REGULATOR device that
+ * was bound by a pmbus_helper based chip driver, decode it through
+ * the chip's pmbus_driver_info (so the MPS DIRECT 1 degC/LSB quirk
+ * and the standard LINEAR11 encoding are both handled), select the
+ * regulator's PAGE first on multi rail parts, and return the result
+ * in millidegrees Celsius.
+ *
+ * This is what the generic drivers/thermal/pmbus_thermal.c companion
+ * calls on its parent; keeping the decode here avoids exposing the
+ * regulator-private pmbus_regulator_priv layout to other subsystems.
+ *
+ * Returns 0 on success, or a negative errno (-ENODEV if reg is not a
+ * probed pmbus regulator, -EIO on bus error).
+ */
+int pmbus_regulator_read_temp(struct udevice *reg_dev, int *temp_mc);
+
+/*
+ * Look up the pmbus_driver_info of a probed UCLASS_REGULATOR device at
+ * (bus_seq, addr) that is driven by a pmbus_helper based chip driver
+ * (mpq8785, pmbus_generic, ...). Probes the device so its identify
+ * hook has run and format[] is populated, then returns its
+ * driver_info. Returns NULL if no such regulator is bound at that
+ * address, if the device is not a pmbus regulator, or if
+ * CONFIG_DM_REGULATOR_PMBUS_HELPER is disabled.
+ *
+ * Lets pmbus_set_active() -- and thus the pmbus CLI and the board
+ * boot snapshots -- reuse the rich, VOUT_MODE detected driver_info of
+ * a DT bound generic / chip regulator when the device is selected by
+ * raw <bus>:<addr> (which has no chip-match registry entry and would
+ * otherwise fall back to blanket LINEAR16 / LINEAR11 decoding).
+ */
+const struct pmbus_driver_info *pmbus_regulator_info_by_addr(int bus_seq,
+ u8 addr);
+
/*
* Status bit name decoding.
*
diff --git a/lib/pmbus.c b/lib/pmbus.c
index d49576ad3bd..920f7b09a4b 100644
--- a/lib/pmbus.c
+++ b/lib/pmbus.c
@@ -761,6 +761,23 @@ int pmbus_set_active(int bus_seq, u8 addr)
sizeof(pmbus_active_state.vendor));
}
+ /*
+ * No MFR_ID chip-match (a spec compliant part with no per chip
+ * driver, e.g. a Flex / Delta PSU): if a generic / chip
+ * UCLASS_REGULATOR is bound at this address, reuse its
+ * VOUT_MODE detected driver_info so telemetry decodes through
+ * the right per class formats instead of the blanket
+ * LINEAR16 / LINEAR11 fallback.
+ */
+ if (CONFIG_IS_ENABLED(DM_REGULATOR_PMBUS_HELPER) &&
+ !pmbus_active_state.info) {
+ const struct pmbus_driver_info *di =
+ pmbus_regulator_info_by_addr(bus_seq, addr);
+
+ if (di)
+ pmbus_active_state.info = di;
+ }
+
/*
* MFR_MODEL / MFR_REVISION are best effort. Use the same byte
* order the matched chip declared; if nothing matched, use the
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v1 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
` (4 subsequent siblings)
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Bo-Chen Chen, David Lechner, Heinrich Schuchardt,
Jaehoon Chung, Jerome Forissier, Julien Masson, Kory Maincent,
Kuan-Wei Chiu, Macpaul Lin, Neil Armstrong, Peng Fan,
Philip Molloy, Quentin Schulz, Raymond Mao, Simon Glass,
Stefan Roese, Tom Rini
Per-chip UCLASS_REGULATOR driver for the MPS MPQ8785 / MPM3695 /
MPM3695-25 / MPM82504 family, layered on the shared pmbus_helper
adapter. Runs Linux's mpq8785_identify() VOUT_MODE switch
(LINEAR16 vs DIRECT m=64 R=1) at probe time, applies the optional
mps,vout-fb-divider-ratio-permille DT property, and walks the
documented MPS ADDR_VBOOT windows on MFR_ID failure so a
die-revision address shift just works.
Publishes the pmbus mps last|clear last|clear force vendor
extension subcommands (NVM PROTECTION_LAST read and clear) when
CMD_PMBUS is enabled.
Adaapted from Linux code.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 2 +
.../regulator/mps,mpq8785.yaml | 105 ++++
drivers/power/regulator/Kconfig | 9 +
drivers/power/regulator/Makefile | 1 +
drivers/power/regulator/mpq8785.c | 494 ++++++++++++++++++
5 files changed, 611 insertions(+)
create mode 100644 doc/device-tree-bindings/regulator/mps,mpq8785.yaml
create mode 100644 drivers/power/regulator/mpq8785.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 4cea3a82852..e22f1ff6641 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1585,7 +1585,9 @@ M: Vincent Jardin <vjardin@free.fr>
S: Maintained
F: cmd/pmbus.c
F: doc/develop/pmbus.rst
+F: doc/device-tree-bindings/regulator/mps,mpq8785.yaml
F: doc/device-tree-bindings/regulator/pmbus.yaml
+F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
diff --git a/doc/device-tree-bindings/regulator/mps,mpq8785.yaml b/doc/device-tree-bindings/regulator/mps,mpq8785.yaml
new file mode 100644
index 00000000000..8d7465d77fa
--- /dev/null
+++ b/doc/device-tree-bindings/regulator/mps,mpq8785.yaml
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/mps,mpq8785.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Monolithic Power Systems multiphase voltage regulators with PMBus (U-Boot subset)
+
+maintainers:
+ - Vincent Jardin <vjardin@free.fr>
+
+description: |
+ Monolithic Power Systems digital multiphase voltage regulators with
+ PMBus.
+
+ This U-Boot subset mirrors the upstream Linux kernel binding at
+ linux/Documentation/devicetree/bindings/hwmon/pmbus/mps,mpq8785.yaml.
+ Compatible strings, property names, and semantics are identical so
+ the same .dts file works under both U-Boot (BL33) and Linux post
+ handoff. Properties that only drive the kernel hwmon publication
+ are accepted and ignored by the U-Boot driver.
+
+ The MPS family (MPQ8785 silicon, plus the MPM3695 / MPM3695-25 /
+ MPM82504 derivatives) reports VIN, IOUT, and TEMPERATURE in DIRECT
+ numeric format with chip specific m / b / R coefficients (see
+ drivers/hwmon/pmbus/mpq8785.c::mpq8785_info in Linux). VOUT format
+ is selected at probe time from VOUT_MODE: bits[7:5] == 0 selects
+ LINEAR16, bits[7:5] == 1 or 2 selects DIRECT m=64 R=1 (the chip's
+ VID mode is coerced to DIRECT by the driver).
+
+ PMBus 7 bit address resolution: the chip's ADDR_VBOOT analog level
+ combined with the MFR_ADDR_PMBUS LSB selects one of three address
+ windows depending on die revision (0x10..0x1F, 0x20..0x2F, or
+ 0x60..0x6F). The board file may carry a runtime scan that auto
+ promotes the first responder if the silicon revision strap drifts
+ away from the DT default.
+
+properties:
+ compatible:
+ enum:
+ - mps,mpm3695
+ - mps,mpm3695-25
+ - mps,mpm82504
+ - mps,mpq8785
+
+ reg:
+ maxItems: 1
+
+ mps,vout-fb-divider-ratio-permille:
+ description:
+ External feedback resistor divider ratio Vfb / Vout, expressed
+ in permille. Written to PMBUS_VOUT_SCALE_LOOP at probe time so
+ VOUT_COMMAND writes drive the rail to the requested voltage when
+ the PCB has an external divider on the VOUT sense path.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ minimum: 1
+ maximum: 4095
+ default: 706
+
+allOf:
+ - $ref: regulator.yaml#
+
+ - if:
+ properties:
+ compatible:
+ enum:
+ - mps,mpm3695
+ - mps,mpm82504
+ then:
+ properties:
+ mps,vout-fb-divider-ratio-permille:
+ maximum: 1023
+
+ - if:
+ properties:
+ compatible:
+ const: mps,mpq8785
+ then:
+ properties:
+ mps,vout-fb-divider-ratio-permille:
+ maximum: 2047
+
+required:
+ - compatible
+ - reg
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ regulator@10 {
+ compatible = "mps,mpq8785";
+ reg = <0x10>;
+ regulator-name = "VDD_CORE";
+ regulator-min-microvolt = < 600000>;
+ regulator-max-microvolt = <1100000>;
+ regulator-boot-on;
+ regulator-always-on;
+ };
+ };
+...
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 5b1a9c3f991..67c9e1fb377 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -581,3 +581,12 @@ config DM_REGULATOR_PMBUS_GENERIC
per chip driver only when chip specific quirks (vendor
registers, VID coercion, ADDR pin auto promotion, non standard
m / b / R coefficients) need handling.
+
+config DM_REGULATOR_MPQ8785
+ bool "MPS MPQ8785 / MPM3695 / MPM82504 PMBus voltage regulator"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Driver for the Monolithic Power Systems MPQ8785 family of
+ digital multiphase voltage regulators with PMBus. Supports
+ MPM3695, MPM3695-25, MPM82504, and MPQ8785. Adapted from the
+ Linux drivers/hwmon/pmbus/mpq8785.c reference.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index b084e9ac4bc..aa3faf2f34f 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -51,3 +51,4 @@ obj-$(CONFIG_DM_REGULATOR_MT6357) += mt6357_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
+obj-$(CONFIG_DM_REGULATOR_MPQ8785) += mpq8785.o
diff --git a/drivers/power/regulator/mpq8785.c b/drivers/power/regulator/mpq8785.c
new file mode 100644
index 00000000000..dc321f0e410
--- /dev/null
+++ b/drivers/power/regulator/mpq8785.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * MPS MPQ8785 / MPM3695 / MPM3695-25 / MPM82504 PMBus voltage
+ * regulator driver. Adapted from
+ * linux/drivers/hwmon/pmbus/mpq8785.c
+ * (Charles Hsu, GPL-2.0-or-later) with the kernel hwmon publication
+ * and caching layers stripped.
+ *
+ * Hooks the shared pmbus_helper UCLASS_REGULATOR ops + adds the MPS
+ * specific identify (VOUT_MODE switch between LINEAR16 and DIRECT
+ * m=64 R=1 for the chip's "VID" mode), the MPS vendor extension
+ * (pmbus mps last|clear last|clear force), and ADDR_VBOOT auto
+ * promotion when the DT declared address fails the MFR_ID probe.
+ */
+
+#include <command.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/bitops.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+/* Chip family identifiers (driver_data). */
+enum mpq_chip_id {
+ MPQ_MPM3695 = 0,
+ MPQ_MPM3695_25 = 1,
+ MPQ_MPM82504 = 2,
+ MPQ_MPQ8785 = 3,
+};
+
+/*
+ * MPS vendor extended command codes (NOT in PMBus 1.3 Part II).
+ *
+ * CLEAR_LAST_FAULT (08h) clears the NVM backed PROTECTION_LAST
+ * register. Gated by MFR_CFG_EXT (F5h)
+ * bit[6] = 1; chip silently no ops if the
+ * gate is cleared.
+ * PROTECTION_LAST (FBh) single event, NVM backed log of the last
+ * protection event. Survives the chip's own
+ * power cycle. The boot time post mortem the
+ * SoC has no other way to obtain.
+ *
+ * NEVER issue CLEAR_LAST_FAULT (08h) implicitly; it would erase the
+ * post mortem trail. Only the explicit pmbus mps clear last and
+ * pmbus mps clear force subcommands write it.
+ */
+#define PMBUS_CLEAR_LAST_FAULT 0x08
+#define MPS_PROTECTION_LAST 0xfb
+
+/*
+ * MFR_CFG_EXT (F5h) is an MPS extended config WORD (16 bits, not a
+ * byte). Bit[6] (MFR_CLR_FAULT_CFG) gates CLEAR_LAST_FAULT (08h)
+ * clearing PROTECTION_LAST. Several other bits are fixed and MUST be
+ * preserved on writeback; always read modify write the full 16 bits,
+ * only flip bit[6], restore on the way out.
+ */
+#define MPS_MFR_CFG_EXT 0xf5
+#define MPS_MFR_CFG_EXT_CLR_LAST_EN BIT(6)
+
+/*
+ * MPQ8785 driver_info (transcribed from Linux's
+ * drivers/hwmon/pmbus/mpq8785.c::mpq8785_info). DIRECT format with
+ * chip specific m / b / R coefficients on VIN, IOUT, TEMPERATURE.
+ * VOUT format is selected at probe time from VOUT_MODE: bits[7:5] == 0
+ * selects LINEAR16, bits[7:5] == 1 or 2 selects DIRECT m=64 R=1.
+ */
+
+/*
+ * MPS-extended STATUS_* bit names. The MPQ8785 family reuses several
+ * bit positions documented as RESERVED / UNKNOWN / NONE_ABOVE /
+ * MFR_SPECIFIC by PMBus 1.3 for chip specific signals. The override
+ * table below substitutes the chip name for the standard one when
+ * the bit is set, leaving every other PMBus 1.3 standard bit
+ * (VOUT_OV, IOUT_OC, TEMP, CML, ...) unchanged.
+ *
+ * STATUS_WORD bit[12] spec MFR_SPECIFIC chip NVM_SUMMARY (NVM
+ * backed PROTECTION_LAST
+ * register is non zero)
+ * STATUS_WORD bit[8] spec UNKNOWN chip WATCH_DOG (internal
+ * calculation FSM watchdog
+ * overflow)
+ * STATUS_WORD bit[0] spec NONE_ABOVE chip DRMOS_FAULT (DrMOS
+ * stage fault)
+ * STATUS_CML bit[4] spec MEMORY chip MTP_CRC_FAULT (NVM
+ * CRC mismatch on restore)
+ * STATUS_CML bit[0] spec OTHER_MEM_LOGIC chip MTP_FAULT (NVM
+ * signature fault)
+ * STATUS_TEMPERATURE bit[0] (PMBus leaves bits[3:0] reserved on
+ * this register) chip
+ * OT_SELF (controller die
+ * OT condition)
+ */
+static const struct pmbus_status_override mpq8785_status_overrides[] = {
+ { PMBUS_STATUS_WORD, BIT(12), "NVM_SUMMARY" },
+ { PMBUS_STATUS_WORD, BIT(8), "WATCH_DOG" },
+ { PMBUS_STATUS_WORD, BIT(0), "DRMOS_FAULT" },
+ { PMBUS_STATUS_CML, BIT(4), "MTP_CRC_FAULT" },
+ { PMBUS_STATUS_CML, BIT(0), "MTP_FAULT" },
+ { PMBUS_STATUS_TEMPERATURE, BIT(0), "OT_SELF" },
+ { /* sentinel */ }
+};
+
+static struct pmbus_driver_info mpq8785_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_direct,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear, /* refined per VOUT_MODE */
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_direct,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_IN] = 4, .b[PSC_VOLTAGE_IN] = 0, .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_CURRENT_OUT] = 16, .b[PSC_CURRENT_OUT] = 0, .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_TEMPERATURE] = 1, .b[PSC_TEMPERATURE] = 0, .R[PSC_TEMPERATURE] = 0,
+ /*
+ * Sensor set this family actually implements with calibrated
+ * coefficients: VIN, VOUT, IOUT, TEMP. READ_IIN / READ_POUT are
+ * ACKed by the silicon but uncalibrated here (the kernel's mpq8646
+ * / mpq8785 drivers expose neither), so declaring the set keeps
+ * pmbus_print_telemetry from printing a bogus POUT / IIN -- matching
+ * the kernel's per-chip sensor list.
+ */
+ .classes_present = BIT(PSC_VOLTAGE_IN) | BIT(PSC_VOLTAGE_OUT) |
+ BIT(PSC_CURRENT_OUT) | BIT(PSC_TEMPERATURE),
+ .status_overrides = mpq8785_status_overrides,
+};
+
+/*
+ * MPM3695 / MPM3695-25 / MPM82504 driver_info: VOUT in DIRECT format
+ * with chip family default m=8 R=2. Other sensor classes default to
+ * LINEAR (the chip family does not document non standard formats for
+ * VIN / IOUT / TEMPERATURE; the helper falls back to LINEAR11 when
+ * the active info is non NULL but format[c] is linear).
+ */
+static struct pmbus_driver_info mpm82504_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_OUT] = 8, .b[PSC_VOLTAGE_OUT] = 0, .R[PSC_VOLTAGE_OUT] = 2,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_linear,
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_linear,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_linear,
+};
+
+/*
+ * Chip match for the framework's pmbus dev <bus>:<addr> raw I2C
+ * path. Used when the operator selects the chip directly by address
+ * instead of by regulator-name; the framework probes MFR_ID, sees
+ * "MPS" (after the byte reverse helper), and caches mpq8785_info.
+ */
+static const struct pmbus_chip_match mpq8785_match = {
+ .mfr_id = "MPS",
+ .mfr_id_reverse = true,
+ .vendor = "mps",
+ .info = &mpq8785_info,
+};
+
+static const struct pmbus_bit mpq_protection_last_bits[] = {
+ { 1u << 15, "INIT_FAULT" },
+ { 1u << 14, "NVM_CRC_ERROR" },
+ { 1u << 13, "NVM_FAULT" },
+ { 1u << 12, "OC_PHASE_FAULT" },
+ { 1u << 11, "OTP_SELF_FAULT" },
+ { 1u << 9, "SWITCH_PRD_FAULT" },
+ { 1u << 8, "VIN_OV_FAULT" },
+ { 1u << 7, "VOUT_OV_FAULT" },
+ { 1u << 6, "VOUT_UV_FAULT" },
+ { 1u << 5, "OC_TOT_FAULT" },
+ { 1u << 4, "VIN_UVLO_FAULT" },
+ { 1u << 3, "DRMOS_OTP" },
+ { /* sentinel */ }
+};
+
+static int mps_require_active(struct udevice **chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+
+ if (!act) {
+ printf("pmbus mps: no active device. Use 'pmbus dev <bus>:<addr>' first.\n");
+ return CMD_RET_FAILURE;
+ }
+ if (strcmp(act->vendor, "mps") != 0) {
+ printf("pmbus mps: active device is not from vendor 'mps' (got '%s')\n",
+ act->vendor[0] ? act->vendor : "(generic)");
+ return CMD_RET_FAILURE;
+ }
+ if (pmbus_active_get_i2c(chip)) {
+ printf("pmbus mps: cannot reach i2c%d:0x%02x\n",
+ act->bus_seq, act->addr);
+ return CMD_RET_FAILURE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_last(struct udevice *chip)
+{
+ u16 prot_last = 0;
+
+ if (pmbus_read_word(chip, MPS_PROTECTION_LAST, &prot_last)) {
+ printf("pmbus mps: PROTECTION_LAST (FBh) read failed\n");
+ return CMD_RET_FAILURE;
+ }
+ printf("PROTECTION_LAST (FBh) = 0x%04x [", prot_last);
+ pmbus_print_bits(prot_last, mpq_protection_last_bits);
+ printf("] (NVM, survives MPQ power cycle)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_clear_last(struct udevice *chip)
+{
+ int ret;
+
+ printf("pmbus mps: WARNING, erasing NVM PROTECTION_LAST (FBh) post mortem\n");
+ ret = dm_i2c_write(chip, PMBUS_CLEAR_LAST_FAULT, NULL, 0);
+ if (ret) {
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) write failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) issued; gated by MFR_CFG_EXT bit[6]\n");
+ printf(" (chip silently no ops if F5h bit[6] = 0; verify by re reading FBh)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_clear_force(struct udevice *chip)
+{
+ u8 wp_orig = 0;
+ u16 cfg_orig = 0, cfg_unlocked;
+ int ret, last_rc = 0, rc;
+
+ printf("pmbus mps: FORCE; temporarily lowering WRITE_PROTECT and MFR_CFG_EXT.CLEAR_LAST_EN\n");
+ printf("pmbus mps: WARNING, erasing NVM PROTECTION_LAST (FBh) post mortem\n");
+
+ ret = pmbus_read_byte(chip, PMBUS_WRITE_PROTECT, &wp_orig);
+ if (ret) {
+ printf("pmbus mps: WRITE_PROTECT (10h) read failed (%d), aborting force\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ ret = pmbus_read_word(chip, MPS_MFR_CFG_EXT, &cfg_orig);
+ if (ret) {
+ printf("pmbus mps: MFR_CFG_EXT (F5h) read failed (%d), aborting force\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus mps: saved WRITE_PROTECT=0x%02x MFR_CFG_EXT=0x%04x\n",
+ wp_orig, cfg_orig);
+
+ if (wp_orig != 0) {
+ u8 wp_open = 0x00;
+
+ ret = dm_i2c_write(chip, PMBUS_WRITE_PROTECT, &wp_open, 1);
+ if (ret) {
+ printf("pmbus mps: WRITE_PROTECT clear failed (%d), chip refuses unlock\n",
+ ret);
+ return CMD_RET_FAILURE;
+ }
+ }
+
+ cfg_unlocked = cfg_orig | MPS_MFR_CFG_EXT_CLR_LAST_EN;
+ ret = pmbus_write_word(chip, MPS_MFR_CFG_EXT, cfg_unlocked);
+ if (ret) {
+ printf("pmbus mps: MFR_CFG_EXT <- 0x%04x failed (%d)\n",
+ cfg_unlocked, ret);
+ goto restore_wp;
+ }
+
+ last_rc = dm_i2c_write(chip, PMBUS_CLEAR_LAST_FAULT, NULL, 0);
+ if (last_rc)
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) write failed (%d) even with gate open\n",
+ last_rc);
+ else
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) issued with MFR_CFG_EXT bit[6]=1, PROTECTION_LAST should now read 0x0000\n");
+
+ rc = pmbus_write_word(chip, MPS_MFR_CFG_EXT, cfg_orig);
+ if (rc)
+ printf("pmbus mps: MFR_CFG_EXT restore failed (%d), gate may stay open until POR\n",
+ rc);
+
+restore_wp:
+ if (wp_orig != 0) {
+ rc = dm_i2c_write(chip, PMBUS_WRITE_PROTECT, &wp_orig, 1);
+ if (rc)
+ printf("pmbus mps: WRITE_PROTECT restore failed (%d), chip stays unlocked until POR\n",
+ rc);
+ }
+
+ return (ret || last_rc) ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int mps_vendor_handler(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ struct udevice *chip;
+ int rc;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+
+ rc = mps_require_active(&chip);
+ if (rc)
+ return rc;
+
+ if (!strcmp(argv[1], "last") && argc == 2)
+ return mps_do_last(chip);
+ if (!strcmp(argv[1], "clear") && argc >= 3) {
+ if (!strcmp(argv[2], "last"))
+ return mps_do_clear_last(chip);
+ if (!strcmp(argv[2], "force"))
+ return mps_do_clear_force(chip);
+ }
+ return CMD_RET_USAGE;
+}
+
+static const struct pmbus_vendor_op mps_vendor_op = {
+ .vendor = "mps",
+ .handler = mps_vendor_handler,
+ .help = "pmbus mps last : read MPS PROTECTION_LAST (FBh)\n"
+ "pmbus mps clear last : issue MPS CLEAR_LAST_FAULT (08h) (DESTRUCTIVE)\n"
+ "pmbus mps clear force : force clear via MFR_CFG_EXT bit[6] (DESTRUCTIVE)\n",
+};
+
+static void mpq8785_identify_vout(struct udevice *i2c_dev)
+{
+ enum pmbus_data_format fmt;
+
+ /*
+ * Let the shared helper read VOUT_MODE and pick the base format
+ * (the single source of truth for the bit layout). The MPS quirk:
+ * this family encodes VOUT in DIRECT with m=64 R=1 whenever
+ * VOUT_MODE reports VID *or* DIRECT -- override the helper's
+ * generic DIRECT m=1 / VID-unwired result in those two modes.
+ * LINEAR and IEEE754 keep the helper's selection unchanged.
+ */
+ fmt = pmbus_regulator_identify_vout(i2c_dev, &mpq8785_info);
+ if (fmt == pmbus_fmt_vid || fmt == pmbus_fmt_direct) {
+ mpq8785_info.format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct;
+ mpq8785_info.m[PSC_VOLTAGE_OUT] = 64;
+ mpq8785_info.b[PSC_VOLTAGE_OUT] = 0;
+ mpq8785_info.R[PSC_VOLTAGE_OUT] = 1;
+ }
+}
+
+/*
+ * The MPQ8785 datasheet revision letter changes which window the
+ * analog ADDR_VBOOT level resolves to. Boards have been observed at
+ * 0x10 (later die rev) versus the 0x20 the original driver assumed.
+ * If the DT declared address fails the MFR_ID probe at probe time,
+ * walk the three documented windows looking for an MPS responder.
+ *
+ * Each window covers 16 consecutive 7 bit I2C addresses; the low
+ * nibble selects the chip's MFR_ADDR_PMBUS slot within the window.
+ */
+#define MPS_ADDR_VBOOT_WINDOW_SIZE 16
+static const u8 mps_addr_window_starts[] = { 0x10, 0x20, 0x60 };
+
+static int mpq8785_probe_addr(struct udevice *bus, u8 addr,
+ struct udevice **chip_out)
+{
+ char id[PMBUS_MFR_STRING_MAX] = "";
+ struct udevice *chip;
+ int ret;
+
+ ret = i2c_get_chip(bus, addr, 1, &chip);
+ if (ret)
+ return ret;
+ ret = pmbus_read_string(chip, PMBUS_MFR_ID, id, sizeof(id), true);
+ if (ret < 0)
+ return ret;
+ if (strncmp(id, "MPS", 3) != 0)
+ return -ENODEV;
+ *chip_out = chip;
+ return 0;
+}
+
+static int mpq8785_scan_windows(struct udevice *bus, u8 *found_addr,
+ struct udevice **chip_out)
+{
+ unsigned int i, j;
+
+ for (i = 0; i < ARRAY_SIZE(mps_addr_window_starts); i++) {
+ for (j = 0; j < MPS_ADDR_VBOOT_WINDOW_SIZE; j++) {
+ u8 addr = mps_addr_window_starts[i] + j;
+
+ if (mpq8785_probe_addr(bus, addr, chip_out) == 0) {
+ *found_addr = addr;
+ return 0;
+ }
+ }
+ }
+ return -ENODEV;
+}
+
+static struct pmbus_driver_info *mpq8785_pick_info(enum mpq_chip_id chip_id)
+{
+ switch (chip_id) {
+ case MPQ_MPM3695:
+ case MPQ_MPM3695_25:
+ case MPQ_MPM82504:
+ return &mpm82504_info;
+ case MPQ_MPQ8785:
+ default:
+ return &mpq8785_info;
+ }
+}
+
+static int mpq8785_probe(struct udevice *dev)
+{
+ enum mpq_chip_id chip_id = (enum mpq_chip_id)dev_get_driver_data(dev);
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ struct pmbus_driver_info *info = mpq8785_pick_info(chip_id);
+ static bool match_registered;
+ static bool vendor_registered;
+ u32 fb_div;
+ int ret;
+
+ ret = pmbus_regulator_probe_common(dev, info, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * Verify the chip answers MFR_ID="MPS" at the DT declared
+ * address. If it doesn't, walk the documented ADDR_VBOOT windows
+ * looking for it (a die rev address shift). On a hit, replace
+ * priv->i2c_dev with the discovered chip handle and continue.
+ */
+ {
+ char id[PMBUS_MFR_STRING_MAX] = "";
+
+ ret = pmbus_read_string(priv->i2c_dev, PMBUS_MFR_ID, id,
+ sizeof(id), true);
+ if (ret < 0 || strncmp(id, "MPS", 3) != 0) {
+ struct udevice *bus = dev_get_parent(dev);
+ struct udevice *promoted;
+ u8 found = 0;
+
+ if (mpq8785_scan_windows(bus, &found, &promoted) == 0) {
+ printf("MPQ8785: DT addr 0x%02x silent, auto promoted to 0x%02x\n",
+ (unsigned int)dev_read_addr(dev), found);
+ priv->i2c_dev = promoted;
+ } else {
+ printf("MPQ8785: no MPS responder found in 0x10..0x1f / 0x20..0x2f / 0x60..0x6f\n");
+ return -ENODEV;
+ }
+ }
+ }
+
+ /* MPQ8785 specific: refine VOUT format from VOUT_MODE. */
+ if (chip_id == MPQ_MPQ8785)
+ mpq8785_identify_vout(priv->i2c_dev);
+
+ /* Apply mps,vout-fb-divider-ratio-permille if present in DT. */
+ fb_div = dev_read_u32_default(dev, "mps,vout-fb-divider-ratio-permille", 0);
+ if (fb_div) {
+ ret = pmbus_regulator_apply_voltage_scale(dev, fb_div);
+ if (ret) {
+ printf("MPQ8785: VOUT_SCALE_LOOP write failed (%d)\n", ret);
+ return ret;
+ }
+ }
+
+ /*
+ * Register the chip match and the MPS vendor handler exactly
+ * once across all bound MPS regulators (a board could legally
+ * carry several). Both registries are global and idempotent
+ * matches return -ENOSPC, so the static guards keep things
+ * tidy.
+ */
+ if (!match_registered) {
+ if (pmbus_register_chip(&mpq8785_match) == 0)
+ match_registered = true;
+ }
+ if (!vendor_registered) {
+ if (pmbus_register_vendor_handler(&mps_vendor_op) == 0)
+ vendor_registered = true;
+ }
+ return 0;
+}
+
+static const struct udevice_id mpq8785_ids[] = {
+ { .compatible = "mps,mpm3695", .data = MPQ_MPM3695 },
+ { .compatible = "mps,mpm3695-25", .data = MPQ_MPM3695_25 },
+ { .compatible = "mps,mpm82504", .data = MPQ_MPM82504 },
+ { .compatible = "mps,mpq8785", .data = MPQ_MPQ8785 },
+ { }
+};
+
+U_BOOT_DRIVER(mpq8785_regulator) = {
+ .name = "mpq8785_regulator",
+ .id = UCLASS_REGULATOR,
+ .of_match = mpq8785_ids,
+ .probe = mpq8785_probe,
+ .ops = &pmbus_regulator_ops,
+ .priv_auto = sizeof(struct pmbus_regulator_priv),
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v1 4/7] board: nxp: vid: introduce PMBus framework support
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (2 preceding siblings ...)
2026-07-02 17:15 ` [PATCH v1 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
` (3 subsequent siblings)
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Alice Guo, Fabio Estevam, Jerome Forissier,
Kory Maincent, Kuan-Wei Chiu, Marek Vasut, NXP i.MX U-Boot Team,
Neil Armstrong, Nobuhiro Iwamatsu, Peng Fan, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese,
Stefano Babic, Tom Rini
Wire board/nxp/common/vid.c into the <pmbus.h> framework so the legacy
NXP AVS path stops carrying its own duplicate copy of the PMBus
protocol and instead consumes the shared constants, decoders, and
transport helpers.
vid.c is the legacy NXP AVS/pre-kernel voltage-trim path for lx2160 CPUs.
It does PMBus to whichever core-rail voltage monitor the board carries:
LTC3882 or ISL68233 are selected with
CONFIG_VOL_MONITOR_LTC3882_*/CONFIG_VOL_MONITOR_ISL68233_*.
Before this change the file kept its own local PMBUS_CMD_* command-code
defines, its own inline LINEAR16 mantissa/exponent math, and called
into I2C through the I2C_READ/I2C_WRITE NXP wrappers in
board/nxp/common/i2c_common.{c,h} which is a parallel implementation of
exactly what <pmbus.h> + lib/pmbus.c provides.
The intent is to make vid.c an consumer of the new PMBus.
Compatibility with the former support:
- CLI unchanged: vdd_override and vdd_read keep their existing
semantics, return codes, and diagnostic output.
- I2C transport unchanged on the wire: the framework's pmbus_*
helpers call dm_i2c_read/dm_i2c_write: the same DM I2C
backing that vid.c's former I2C_READ/I2C_WRITE macros already
routed through on DM_I2C.
- Numeric decode is bit-equivalent: pmbus_reg2data_linear16() and
pmbus_data2reg_linear16() implement the PMBus 1.3 Part II
mantissa/exponent.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 2 +
arch/Kconfig.nxp | 4 +
board/nxp/common/vid.c | 104 +++++++++--------
board/nxp/common/vid.h | 15 ++-
.../regulator/lltc,ltc3882.yaml | 91 +++++++++++++++
.../regulator/renesas,isl68233.yaml | 105 ++++++++++++++++++
6 files changed, 266 insertions(+), 55 deletions(-)
create mode 100644 doc/device-tree-bindings/regulator/lltc,ltc3882.yaml
create mode 100644 doc/device-tree-bindings/regulator/renesas,isl68233.yaml
diff --git a/MAINTAINERS b/MAINTAINERS
index e22f1ff6641..94c342036d9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1585,8 +1585,10 @@ M: Vincent Jardin <vjardin@free.fr>
S: Maintained
F: cmd/pmbus.c
F: doc/develop/pmbus.rst
+F: doc/device-tree-bindings/regulator/lltc,ltc3882.yaml
F: doc/device-tree-bindings/regulator/mps,mpq8785.yaml
F: doc/device-tree-bindings/regulator/pmbus.yaml
+F: doc/device-tree-bindings/regulator/renesas,isl68233.yaml
F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
diff --git a/arch/Kconfig.nxp b/arch/Kconfig.nxp
index ef9087d0197..152692e3230 100644
--- a/arch/Kconfig.nxp
+++ b/arch/Kconfig.nxp
@@ -242,24 +242,28 @@ config VOL_MONITOR_IR36021_SET
config VOL_MONITOR_LTC3882_READ
bool "Enable the LTC3882 voltage monitor read"
+ select PMBUS
help
This option enables LTC3882 voltage monitor read
functionality. It is used by the common VID driver.
config VOL_MONITOR_LTC3882_SET
bool "Enable the LTC3882 voltage monitor set"
+ select PMBUS
help
This option enables LTC3882 voltage monitor set
functionality. It is used by the common VID driver.
config VOL_MONITOR_ISL68233_READ
bool "Enable the ISL68233 voltage monitor read"
+ select PMBUS
help
This option enables ISL68233 voltage monitor read
functionality. It is used by the common VID driver.
config VOL_MONITOR_ISL68233_SET
bool "Enable the ISL68233 voltage monitor set"
+ select PMBUS
help
This option enables ISL68233 voltage monitor set
functionality. It is used by the common VID driver.
diff --git a/board/nxp/common/vid.c b/board/nxp/common/vid.c
index 84cb43fad56..a91d6c9381a 100644
--- a/board/nxp/common/vid.c
+++ b/board/nxp/common/vid.c
@@ -11,6 +11,7 @@
#include <i2c.h>
#include <irq_func.h>
#include <log.h>
+#include <pmbus.h>
#include <vsprintf.h>
#include <asm/io.h>
#ifdef CONFIG_FSL_LSCH2
@@ -260,45 +261,38 @@ static int read_voltage_from_IR(int i2caddress)
*/
#define VOUT_WARNING "VID: VOUT_MODE exponent has resolution worse than 1 V!\n"
-/* Checks the PMBus voltage monitor for the format used for voltage values */
-static int get_pmbus_multiplier(DEVICE_HANDLE_T dev)
+/*
+ * Read VOUT_MODE for downstream LINEAR16 decode/encode through the
+ * tree level <pmbus.h> helpers (pmbus_reg2data_linear16,
+ * pmbus_data2reg_linear16). Returns the raw VOUT_MODE byte on
+ * success, or 0 on bus error. Emits VOUT_WARNING on Linear mode
+ * chips with a non negative exponent (resolution >= 1 V is unusable
+ * for sub volt SoC rails) and an informational note on the
+ * unsupported VID format.
+ */
+static u8 vid_read_vout_mode(DEVICE_HANDLE_T dev)
{
- u8 mode;
- int exponent, multiplier, ret;
+ u8 mode = 0;
+ int ret;
- ret = I2C_READ(dev, PMBUS_CMD_VOUT_MODE, &mode, sizeof(mode));
+ ret = pmbus_read_byte(dev, PMBUS_VOUT_MODE, &mode);
if (ret) {
printf("VID: unable to determine voltage multiplier\n");
- return 1;
+ return 0;
}
- /* Upper 3 bits is mode, lower 5 bits is exponent */
- exponent = (int)mode & 0x1F;
- mode >>= 5;
- switch (mode) {
- case 0:
- /* Linear, 5 bit twos component exponent */
- if (exponent & 0x10) {
- multiplier = 1 << (16 - (exponent & 0xF));
- } else {
- /* If exponent is >= 0, then resolution is 1 V! */
+ switch (mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ if (!(mode & 0x10))
printf(VOUT_WARNING);
- multiplier = 1;
- }
break;
- case 1:
- /* VID code identifier */
+ case PB_VOUT_MODE_VID:
printf("VID: custom VID codes are not supported\n");
- multiplier = MV_PER_V;
break;
default:
- /* Direct, in mV */
- multiplier = MV_PER_V;
break;
}
-
- debug("VID: calculated multiplier is %d\n", multiplier);
- return multiplier;
+ return mode;
}
#endif
@@ -306,8 +300,8 @@ static int get_pmbus_multiplier(DEVICE_HANDLE_T dev)
defined(CONFIG_VOL_MONITOR_LTC3882_READ)
static int read_voltage_from_pmbus(int i2caddress)
{
- int ret, multiplier, vout;
- u8 channel = PWM_CHANNEL0;
+ int ret, vout;
+ u8 channel = PWM_CHANNEL0, vout_mode;
u16 vcode;
DEVICE_HANDLE_T dev;
@@ -317,25 +311,31 @@ static int read_voltage_from_pmbus(int i2caddress)
return ret;
/* Select the right page */
- ret = I2C_WRITE(dev, PMBUS_CMD_PAGE, &channel, sizeof(channel));
+ ret = pmbus_write_byte(dev, PMBUS_PAGE, channel);
if (ret) {
printf("VID: failed to select VDD page %d\n", channel);
return ret;
}
- /* VOUT is little endian */
- ret = I2C_READ(dev, PMBUS_CMD_READ_VOUT, (void *)&vcode, sizeof(vcode));
+ ret = pmbus_read_word(dev, PMBUS_READ_VOUT, &vcode);
if (ret) {
printf("VID: failed to read core voltage\n");
return ret;
}
- /* Scale down to the real mV */
- multiplier = get_pmbus_multiplier(dev);
- vout = (int)vcode;
- /* Multiplier 1000 (direct mode) requires no change to convert */
- if (multiplier != MV_PER_V)
- vout = DIV_ROUND_UP(vout * MV_PER_V, multiplier);
+ /*
+ * Decode LINEAR16 via the tree level helper from <pmbus.h>. For
+ * non Linear VOUT_MODE settings the helper returns 0; fall back
+ * to the historic mV pass through so existing LSCH boards keep.
+ */
+ vout_mode = vid_read_vout_mode(dev);
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) == PB_VOUT_MODE_LINEAR) {
+ s64 uv = pmbus_reg2data_linear16(vcode, vout_mode);
+
+ vout = (int)((uv + 500) / 1000); /* round to mV */
+ } else {
+ vout = (int)vcode;
+ }
return vout - board_vdd_drop_compensation();
}
#endif
@@ -463,11 +463,13 @@ static int set_voltage_to_IR(int i2caddress, int vdd)
static int set_voltage_to_pmbus(int i2caddress, int vdd)
{
int ret, vdd_last, vdd_target = vdd;
- int count = MAX_LOOP_WAIT_NEW_VOL, temp = 0, multiplier;
+ int count = MAX_LOOP_WAIT_NEW_VOL, temp = 0;
+ u8 vout_mode;
+ u16 raw;
unsigned char value;
/* The data to be sent with the PMBus command PAGE_PLUS_WRITE */
- u8 buffer[5] = { 0x04, PWM_CHANNEL0, PMBUS_CMD_VOUT_COMMAND, 0, 0 };
+ u8 buffer[5] = { 0x04, PWM_CHANNEL0, PMBUS_VOUT_COMMAND, 0, 0 };
DEVICE_HANDLE_T dev;
/* Open device handle */
@@ -475,24 +477,28 @@ static int set_voltage_to_pmbus(int i2caddress, int vdd)
if (ret)
return ret;
- /* Scale up to the proper value for the VOUT command, little endian */
- multiplier = get_pmbus_multiplier(dev);
+ /*
+ * Encode target mV as LINEAR16 raw via the tree level helper
+ * from <pmbus.h>. For non Linear VOUT_MODE settings the helper
+ * returns 0; fall back to the historic mV pass through.
+ */
vdd += board_vdd_drop_compensation();
- if (multiplier != MV_PER_V)
- vdd = DIV_ROUND_UP(vdd * multiplier, MV_PER_V);
- buffer[3] = vdd & 0xFF;
- buffer[4] = (vdd & 0xFF00) >> 8;
+ vout_mode = vid_read_vout_mode(dev);
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) == PB_VOUT_MODE_LINEAR)
+ raw = pmbus_data2reg_linear16((s64)vdd * 1000LL, vout_mode);
+ else
+ raw = (u16)vdd;
+ buffer[3] = raw & 0xFF;
+ buffer[4] = (raw & 0xFF00) >> 8;
/* Check write protect state */
- ret = I2C_READ(dev, PMBUS_CMD_WRITE_PROTECT, (void *)&value,
- sizeof(value));
+ ret = pmbus_read_byte(dev, PMBUS_WRITE_PROTECT, &value);
if (ret)
goto exit;
if (value != EN_WRITE_ALL_CMD) {
value = EN_WRITE_ALL_CMD;
- ret = I2C_WRITE(dev, PMBUS_CMD_WRITE_PROTECT,
- (void *)&value, sizeof(value));
+ ret = pmbus_write_byte(dev, PMBUS_WRITE_PROTECT, value);
if (ret)
goto exit;
}
diff --git a/board/nxp/common/vid.h b/board/nxp/common/vid.h
index b34c080b4ba..72c1c089aa1 100644
--- a/board/nxp/common/vid.h
+++ b/board/nxp/common/vid.h
@@ -22,8 +22,9 @@
#define IR_VDD_STEP_UP 5
/* LTC3882 */
-#define PMBUS_CMD_WRITE_PROTECT 0x10
/*
+ * PMBUS_WRITE_PROTECT (10h) provided by <pmbus.h>
+ *
* WRITE_PROTECT command supported values
* 0x80: Disable all writes except WRITE_PROTECT, PAGE,
* STORE_USER_ALL and MFR_EE_UNLOCK commands.
@@ -51,12 +52,14 @@
#define VDD_MV_MAX 925
#endif
-/* PM Bus commands code for LTC3882*/
+/*
+ * PM Bus commands code for LTC3882. PMBUS_PAGE / PMBUS_READ_VOUT /
+ * PMBUS_VOUT_MODE / PMBUS_VOUT_COMMAND are provided by <pmbus.h>.
+ * PMBUS_CMD_PAGE_PLUS_WRITE (05h) is the LTC3882 SMBus block write
+ * transaction not in <pmbus.h>'s standard subset, so keep its
+ * definition here.
+ */
#define PWM_CHANNEL0 0x0
-#define PMBUS_CMD_PAGE 0x0
-#define PMBUS_CMD_READ_VOUT 0x8B
-#define PMBUS_CMD_VOUT_MODE 0x20
-#define PMBUS_CMD_VOUT_COMMAND 0x21
#define PMBUS_CMD_PAGE_PLUS_WRITE 0x05
#if defined(CONFIG_TARGET_LX2160AQDS) || defined(CONFIG_TARGET_LX2162AQDS) || \
diff --git a/doc/device-tree-bindings/regulator/lltc,ltc3882.yaml b/doc/device-tree-bindings/regulator/lltc,ltc3882.yaml
new file mode 100644
index 00000000000..7ed49d04a87
--- /dev/null
+++ b/doc/device-tree-bindings/regulator/lltc,ltc3882.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/lltc,ltc3882.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Linear Technology LTC3882 dual output PMBus DC/DC controller (U-Boot subset)
+
+maintainers:
+ - Vincent Jardin <vjardin@free.fr>
+
+description: |
+ Dual output PolyPhase synchronous step down DC/DC controller with
+ digital power system management over PMBus.
+
+ This U-Boot subset mirrors the upstream Linux kernel binding at
+ linux/Documentation/devicetree/bindings/hwmon/lltc,ltc2978.yaml
+ (which covers the whole Linear / ADI pmbus family including the
+ LTC3882). Compatible strings, property names, and semantics are
+ identical so the same .dts file works under both U-Boot (BL33) and
+ Linux post handoff. Properties that only drive the kernel hwmon
+ publication are accepted and ignored by the U-Boot driver.
+
+ VOUT is reported in PMBus LINEAR16 format with the exponent
+ supplied by VOUT_MODE bits[4:0]. VIN, IIN, IOUT, and TEMPERATURE
+ use LINEAR11 (signed 5 bit exponent, signed 11 bit mantissa).
+
+ On NXP Layerscape boards (LX2160A class), the legacy AVS code in
+ board/nxp/common/vid.c speaks PMBus to the LTC3882 to read VOUT
+ and to write VOUT_COMMAND for pre kernel core voltage trim. That
+ path uses the legacy non DM I2C transport (fsl_i2c) and so does
+ not bind through this DT node today; the binding is published for
+ schema validation, for future U-Boot driver model migration, and
+ for matching the upstream Linux .dts.
+
+properties:
+ compatible:
+ enum:
+ - lltc,ltc3882
+
+ reg:
+ maxItems: 1
+
+ regulators:
+ type: object
+ description: |
+ Container for the two output rails the LTC3882 exposes
+ (vout0 and vout1). Each child node is a regulator described
+ by the standard regulator binding; child names indicate which
+ PMBus PAGE the rail maps to (vout0 = page 0, vout1 = page 1).
+
+ patternProperties:
+ "^vout[01]$":
+ $ref: /schemas/regulator/regulator.yaml#
+ type: object
+ unevaluatedProperties: false
+
+ additionalProperties: false
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ regulator@5e {
+ compatible = "lltc,ltc3882";
+ reg = <0x5e>;
+
+ regulators {
+ vout0 {
+ regulator-name = "VDD_CORE";
+ regulator-min-microvolt = < 775000>;
+ regulator-max-microvolt = < 925000>;
+ regulator-boot-on;
+ };
+ vout1 {
+ regulator-name = "VDD_PLAT";
+ regulator-min-microvolt = < 850000>;
+ regulator-max-microvolt = <1000000>;
+ };
+ };
+ };
+ };
+...
diff --git a/doc/device-tree-bindings/regulator/renesas,isl68233.yaml b/doc/device-tree-bindings/regulator/renesas,isl68233.yaml
new file mode 100644
index 00000000000..41f18381942
--- /dev/null
+++ b/doc/device-tree-bindings/regulator/renesas,isl68233.yaml
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/renesas,isl68233.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas ISL68233 digital multiphase voltage regulator with PMBus (U-Boot subset)
+
+maintainers:
+ - Vincent Jardin <vjardin@free.fr>
+
+description: |
+ Renesas (formerly Intersil) digital multiphase voltage regulator
+ with PMBus.
+
+ This U-Boot subset mirrors the upstream Linux kernel binding at
+ linux/Documentation/devicetree/bindings/hwmon/pmbus/isil,isl68137.yaml,
+ which covers the whole Intersil / Renesas ISL family including the
+ ISL68233. Compatible strings, property names, and semantics are
+ identical so the same .dts file works under both U-Boot (BL33) and
+ Linux post handoff. Properties that only drive the kernel hwmon
+ publication are accepted and ignored by the U-Boot driver.
+
+ VOUT is reported in PMBus LINEAR16 format with the exponent
+ supplied by VOUT_MODE bits[4:0]. VIN, IIN, IOUT, and TEMPERATURE
+ use LINEAR11 (signed 5 bit exponent, signed 11 bit mantissa). The
+ ISL68233 exposes multiple output rails through PMBus PAGE
+ switching; per channel sub nodes follow the upstream pattern.
+
+ On NXP Layerscape boards, the legacy AVS code in
+ board/nxp/common/vid.c speaks PMBus to the ISL68233 to read VOUT
+ and to write VOUT_COMMAND for pre kernel core voltage trim. That
+ path uses the legacy non DM I2C transport (fsl_i2c) and so does
+ not bind through this DT node today; the binding is published for
+ schema validation, for future U-Boot driver model migration, and
+ for matching the upstream Linux .dts.
+
+properties:
+ compatible:
+ enum:
+ - renesas,isl68233
+
+ reg:
+ maxItems: 1
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+patternProperties:
+ "^channel@([0-3])$":
+ type: object
+ description:
+ Container for properties specific to a particular channel (rail).
+
+ properties:
+ reg:
+ description: The channel (rail) index.
+ items:
+ minimum: 0
+ maximum: 3
+
+ vout-voltage-divider:
+ description: |
+ Resistances of a voltage divider placed between Vout and
+ the voltage sense (Vsense) pin for the given channel. Two
+ numbers <Rout Rtotal> which yields an adjusted Vout as
+ Vout_adj = Vout * Rtotal / Rout, given the original Vout
+ as reported by the Vsense pin.
+ $ref: /schemas/types.yaml#/definitions/uint32-array
+ minItems: 2
+ maxItems: 2
+
+ required:
+ - reg
+
+ additionalProperties: false
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ regulator@60 {
+ compatible = "renesas,isl68233";
+ reg = <0x60>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ channel@0 {
+ reg = <0>;
+ vout-voltage-divider = <1000 2000>;
+ };
+ };
+ };
+...
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v1 5/7] thermal: pmbus: add PMBus die-temp driver
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (3 preceding siblings ...)
2026-07-02 17:15 ` [PATCH v1 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
` (2 subsequent siblings)
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Jerome Forissier, Kory Maincent, Kuan-Wei Chiu,
Marek Vasut, Neil Armstrong, Peng Fan, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
The driver is a thin UCLASS_THERMAL: its get_temp reads the
temperature of its parent regulator through the pmbus helper
(READ_TEMPERATURE_1), without any chip-specific code.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 1 +
drivers/thermal/Kconfig | 8 ++++++++
drivers/thermal/Makefile | 1 +
drivers/thermal/pmbus_thermal.c | 33 +++++++++++++++++++++++++++++++++
4 files changed, 43 insertions(+)
create mode 100644 drivers/thermal/pmbus_thermal.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 94c342036d9..258c0d9bc18 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1593,6 +1593,7 @@ F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
+F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 91c39aa4dee..30bb64ce895 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -55,4 +55,12 @@ config TI_LM74_THERMAL
Enable thermal support for the Texas Instruments LM74 chip.
The driver supports reading CPU temperature.
+config PMBUS_THERMAL
+ bool "Generic PMBus temperature"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Expose the die-temperature reading of any PMBus voltage
+ regulator bound by a pmbus_helper based chip driver
+ as a UCLASS_THERMAL device.
+
endif # if DM_THERMAL
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index b6f06c00ed9..25435f43b64 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_RCAR_GEN3_THERMAL) += rcar_gen3_thermal.o
obj-$(CONFIG_SANDBOX) += thermal_sandbox.o
obj-$(CONFIG_TI_DRA7_THERMAL) += ti-bandgap.o
obj-$(CONFIG_TI_LM74_THERMAL) += ti-lm74.o
+obj-$(CONFIG_PMBUS_THERMAL) += pmbus_thermal.o
diff --git a/drivers/thermal/pmbus_thermal.c b/drivers/thermal/pmbus_thermal.c
new file mode 100644
index 00000000000..c251cea8ddf
--- /dev/null
+++ b/drivers/thermal/pmbus_thermal.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Generic UCLASS_THERMAL companion for PMBus voltage regulators.
+ *
+ * Works with any chip bound by a pmbus_helper based regulator driver
+ * (drivers/power/regulator/<chip>.c calling
+ * pmbus_regulator_probe_common()). It auto-spawns one
+ * of these thermal devices per regulator.
+ *
+ * The reading is the chip's READ_TEMPERATURE_1 (PMBus 0x8D), decoded
+ * through the parent's pmbus_driver_info.
+ */
+
+#include <dm.h>
+#include <pmbus.h>
+#include <thermal.h>
+
+static int pmbus_thermal_get_temp(struct udevice *dev, int *temp)
+{
+ return pmbus_regulator_read_temp(dev_get_parent(dev), temp);
+}
+
+static const struct dm_thermal_ops pmbus_thermal_ops = {
+ .get_temp = pmbus_thermal_get_temp,
+};
+
+U_BOOT_DRIVER(pmbus_thermal) = {
+ .name = "pmbus_thermal",
+ .id = UCLASS_THERMAL,
+ .ops = &pmbus_thermal_ops,
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v1 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (4 preceding siblings ...)
2026-07-02 17:15 ` [PATCH v1 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
@ 2026-07-02 17:15 ` Vincent Jardin
2026-07-02 17:26 ` [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Tom Rini
2026-07-02 17:46 ` [PATCH v1 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:15 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Anshul Dalal, Bo-Chen Chen, David Lechner,
Dinesh Maniyam, Heiko Schocher, Heinrich Schuchardt,
Jaehoon Chung, Jerome Forissier, Julien Masson, Kory Maincent,
Kuan-Wei Chiu, Lucien.Jheng, Marek Vasut, Martin Schwan,
Mattijs Korpershoek, Michal Simek, Neil Armstrong, Peng Fan,
Philip Molloy, Pieter Van Trappen, Quentin Schulz,
Rasmus Villemoes, Raymond Mao, Simon Glass, Stefan Roese,
Svyatoslav Ryhel, Tom Rini
Add a UCLASS_I2C_EMUL driver that emulates a PMBus 1.x compliant chip
behind the sandbox I2C bus, plus the test.dts wiring and sandbox
defconfig that bind it to the generic PMBus regulator
(compatible = "pmbus"). This design is a stub only: it lets the
follow-up dm unit test drive lib/pmbus.c, the generic regulator and
the pmbus CLI command with no real hardware.
The emulator models a flat per-command 16-bit register file and the
three identification block strings (MFR_ID / MFR_MODEL /
MFR_REVISION). READ_IIN and READ_POUT are deliberately left
unimplemented (the chip NAKs them) so the telemetry printer's
"(not supported)" path is exercised, mirroring a real buck that only
calibrates a subset of the sensor classes.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 1 +
arch/sandbox/dts/test.dts | 10 ++
configs/sandbox_defconfig | 6 +
drivers/power/regulator/Kconfig | 10 ++
drivers/power/regulator/Makefile | 1 +
drivers/power/regulator/sandbox_pmbus.c | 160 ++++++++++++++++++++++++
6 files changed, 188 insertions(+)
create mode 100644 drivers/power/regulator/sandbox_pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 258c0d9bc18..bdfb660a743 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1593,6 +1593,7 @@ F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
+F: drivers/power/regulator/sandbox_pmbus.c
F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 0887de4333b..5032eecceea 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -1027,6 +1027,9 @@
emul1: emull {
compatible = "sandbox,i2c-rtc-emul";
};
+ emul_pmbus: emul-pmbus {
+ compatible = "sandbox,i2c-pmbus";
+ };
};
sandbox_pmic: sandbox_pmic@40 {
@@ -1038,6 +1041,13 @@
reg = <0x41>;
sandbox,emul = <&emul_pmic1>;
};
+
+ pmbus@70 {
+ reg = <0x70>;
+ compatible = "pmbus";
+ regulator-name = "sandbox-pmbus-vout";
+ sandbox,emul = <&emul_pmbus>;
+ };
};
i3c0 {
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index ba800f7d19d..de90a2b39e5 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -392,3 +392,9 @@ CONFIG_UTHREAD=y
CONFIG_UNIT_TEST=y
CONFIG_UT_TIME=y
CONFIG_UT_DM=y
+CONFIG_PMBUS=y
+CONFIG_CMD_PMBUS=y
+CONFIG_DM_REGULATOR_PMBUS_HELPER=y
+CONFIG_DM_REGULATOR_PMBUS_GENERIC=y
+CONFIG_SANDBOX_PMBUS=y
+CONFIG_PMBUS_THERMAL=y
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 67c9e1fb377..143911eeb17 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -590,3 +590,13 @@ config DM_REGULATOR_MPQ8785
digital multiphase voltage regulators with PMBus. Supports
MPM3695, MPM3695-25, MPM82504, and MPQ8785. Adapted from the
Linux drivers/hwmon/pmbus/mpq8785.c reference.
+
+config SANDBOX_PMBUS
+ bool "Sandbox PMBus 1.x chip emulator"
+ depends on SANDBOX && PMBUS && DM_I2C
+ help
+ Emulate a PMBus 1.x compliant chip behind a sandbox I2C bus so
+ the PMBus framework (lib/pmbus.c), the generic regulator
+ (DM_REGULATOR_PMBUS_GENERIC) and the pmbus CLI command can be
+ exercised by the dm unit tests with no real hardware. Only
+ useful for testing; say N on real boards.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index aa3faf2f34f..b8599ea7fd9 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -52,3 +52,4 @@ obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
obj-$(CONFIG_DM_REGULATOR_MPQ8785) += mpq8785.o
+obj-$(CONFIG_SANDBOX_PMBUS) += sandbox_pmbus.o
diff --git a/drivers/power/regulator/sandbox_pmbus.c b/drivers/power/regulator/sandbox_pmbus.c
new file mode 100644
index 00000000000..2900d0a6d83
--- /dev/null
+++ b/drivers/power/regulator/sandbox_pmbus.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Sandbox PMBus 1.x chip stub (UCLASS_I2C_EMUL).
+ *
+ * Stub a DT i2c node so the PMBus framework, the generic pmbus
+ * regulator and the pmbus CLI command can be tested.
+ * The model is a flat per-command 16 bit
+ * register file combined with some fixed identification strings.
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <pmbus.h>
+#include <linux/ctype.h>
+
+#define PMBUS_EMUL_NREG 256
+
+struct sandbox_pmbus_priv {
+ u16 reg[PMBUS_EMUL_NREG];
+ bool supported[PMBUS_EMUL_NREG];
+};
+
+/* Identification strings reported in the natural (forward) byte order. */
+static const char *pmbus_emul_string(u8 cmd)
+{
+ switch (cmd) {
+ case PMBUS_MFR_ID:
+ return "SANDBOX";
+ case PMBUS_MFR_MODEL:
+ return "PMBUS-EMUL";
+ case PMBUS_MFR_REVISION:
+ return "1.0";
+ default:
+ return NULL;
+ }
+}
+
+static int sandbox_pmbus_read(struct sandbox_pmbus_priv *priv, u8 cmd,
+ u8 *buf, int len)
+{
+ const char *str = pmbus_emul_string(cmd);
+ int i;
+
+ if (str) {
+ int slen = strlen(str);
+
+ /* Block payload: [length][bytes...]. */
+ buf[0] = (u8)slen;
+ for (i = 1; i < len; i++)
+ buf[i] = (i - 1 < slen) ? (u8)str[i - 1] : 0;
+ return 0;
+ }
+
+ if (!priv->supported[cmd])
+ return -EREMOTEIO; /* chip NAKs an unimplemented command */
+
+ for (i = 0; i < len; i++)
+ buf[i] = (u8)(priv->reg[cmd] >> (8 * i));
+ return 0;
+}
+
+static int sandbox_pmbus_write(struct sandbox_pmbus_priv *priv, u8 cmd,
+ const u8 *buf, int len)
+{
+ if (len == 0)
+ return 0; /* send-byte (eg CLEAR_FAULTS): just ACK */
+ if (!priv->supported[cmd])
+ return -EREMOTEIO;
+ if (len == 1)
+ priv->reg[cmd] = buf[0];
+ else
+ priv->reg[cmd] = (u16)buf[0] | ((u16)buf[1] << 8);
+ return 0;
+}
+
+static int sandbox_pmbus_xfer(struct udevice *emul, struct i2c_msg *msg,
+ int nmsgs)
+{
+ struct sandbox_pmbus_priv *priv = dev_get_priv(emul);
+ u8 cmd;
+
+ if (nmsgs == 0)
+ return 0;
+ /* A PMBus transaction always opens with the command-code write. */
+ if (msg[0].flags & I2C_M_RD)
+ return -EIO;
+ if (msg[0].len == 0)
+ return 0; /* address-only probe */
+ cmd = msg[0].buf[0];
+
+ if (nmsgs >= 2 && (msg[1].flags & I2C_M_RD))
+ return sandbox_pmbus_read(priv, cmd, msg[1].buf, msg[1].len);
+
+ return sandbox_pmbus_write(priv, cmd, msg[0].buf + 1, msg[0].len - 1);
+}
+
+static void sandbox_pmbus_support(struct sandbox_pmbus_priv *priv, u8 cmd,
+ u16 val)
+{
+ priv->supported[cmd] = true;
+ priv->reg[cmd] = val;
+}
+
+static int sandbox_pmbus_probe(struct udevice *emul)
+{
+ struct sandbox_pmbus_priv *priv = dev_get_priv(emul);
+
+ /* Configuration / identification. */
+ sandbox_pmbus_support(priv, PMBUS_PAGE, 0);
+ sandbox_pmbus_support(priv, PMBUS_OPERATION, PB_OPERATION_ON);
+ sandbox_pmbus_support(priv, PMBUS_ON_OFF_CONFIG, 0);
+ sandbox_pmbus_support(priv, PMBUS_WRITE_PROTECT, 0);
+ sandbox_pmbus_support(priv, PMBUS_CAPABILITY, 0xb0);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_MODE, 0x18); /* LINEAR 2^-8 */
+ sandbox_pmbus_support(priv, PMBUS_VOUT_COMMAND, 0x0200);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_TRIM, 0);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_MAX, 0x0400);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_SCALE_LOOP, 0);
+ sandbox_pmbus_support(priv, PMBUS_REVISION, PMBUS_REV_13);
+
+ /* Status registers, all clean. */
+ sandbox_pmbus_support(priv, PMBUS_STATUS_BYTE, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_WORD, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_VOUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_IOUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_INPUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_TEMPERATURE, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_CML, 0);
+
+ /*
+ * Telemetry the emulated chip implements. READ_IIN and READ_POUT
+ * are intentionally absent so callers see the unsupported path.
+ */
+ sandbox_pmbus_support(priv, PMBUS_READ_VIN, 0x0abc);
+ sandbox_pmbus_support(priv, PMBUS_READ_VOUT, 0x0200);
+ sandbox_pmbus_support(priv, PMBUS_READ_IOUT, 0x0123);
+ sandbox_pmbus_support(priv, PMBUS_READ_TEMPERATURE_1, 0x0019);
+
+ return 0;
+}
+
+static struct dm_i2c_ops sandbox_pmbus_emul_ops = {
+ .xfer = sandbox_pmbus_xfer,
+};
+
+static const struct udevice_id sandbox_pmbus_ids[] = {
+ { .compatible = "sandbox,i2c-pmbus" },
+ { }
+};
+
+U_BOOT_DRIVER(sandbox_pmbus_emul) = {
+ .name = "sandbox_pmbus_emul",
+ .id = UCLASS_I2C_EMUL,
+ .of_match = sandbox_pmbus_ids,
+ .probe = sandbox_pmbus_probe,
+ .priv_auto = sizeof(struct sandbox_pmbus_priv),
+ .ops = &sandbox_pmbus_emul_ops,
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* Re: [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (5 preceding siblings ...)
2026-07-02 17:15 ` [PATCH v1 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
@ 2026-07-02 17:26 ` Tom Rini
2026-07-02 23:06 ` Vincent Jardin
2026-07-02 17:46 ` [PATCH v1 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
7 siblings, 1 reply; 24+ messages in thread
From: Tom Rini @ 2026-07-02 17:26 UTC (permalink / raw)
To: Vincent Jardin
Cc: u-boot, Alexey Charkov, Alice Guo, Andrew Goodbody, Anshul Dalal,
Bo-Chen Chen, Brian Sune, David Lechner, Dinesh Maniyam,
Fabio Estevam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jaehoon Chung,
Jerome Forissier, Julien Masson, Julien Stephan, Kory Maincent,
Kuan-Wei Chiu, Lucien.Jheng, Macpaul Lin, Marek Vasut,
Marek Vasut, Martin Schwan, Mateusz Furdyna, Mattijs Korpershoek,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
NXP i.MX U-Boot Team, Neil Armstrong, Nobuhiro Iwamatsu, Peng Fan,
Peter Robinson, Philip Molloy, Pieter Van Trappen, Quentin Schulz,
Rasmus Villemoes, Raymond Mao, Simon Glass, Stefan Roese,
Stefano Babic, Svyatoslav Ryhel
[-- Attachment #1: Type: text/plain, Size: 1180 bytes --]
On Thu, Jul 02, 2026 at 07:15:44PM +0200, Vincent Jardin wrote:
>
> This series adds U-Boot's PMBus 1.x support as a small boot-time
> layer (not a hwmon clone):
>
> - a decoder + transport library and the pmbus CLI command
> - a shared UCLASS_REGULATOR adapter plus a catch-all driver for
> compliant chips, add the MPS MPQ8785 per-chip driver
> - a generic PMBus die-temperature UCLASS_THERMAL bridge
> - migration of the shared NXP VID rail-trim code to this framework
> - a sandbox PMBus chip emulator and "ut dm pmbus" unit tests that
> exercise most subcommand of the CLI.
>
> The goal is to identify PMBus regulators at boot, print telemetry and
> decode chip alerts before the kernel takes over - no polling, no
> sysfs, no fan loops. Linux owns the runtime side.
[snip]
> .../regulator/lltc,ltc3882.yaml | 91 ++
> .../regulator/mps,mpq8785.yaml | 105 +++
> doc/device-tree-bindings/regulator/pmbus.yaml | 65 ++
> .../regulator/renesas,isl68233.yaml | 105 +++
We should be using, and referencing, the unmodified versions of these
files in dts/upstream instead, thanks.
--
Tom
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
^ permalink raw reply [flat|nested] 24+ messages in thread
* [PATCH v1 7/7] test: dm: pmbus: test pmbus command and framework
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (6 preceding siblings ...)
2026-07-02 17:26 ` [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Tom Rini
@ 2026-07-02 17:46 ` Vincent Jardin
7 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 17:46 UTC (permalink / raw)
To: u-boot; +Cc: Simon Glass, Tom Rini
Add dm unit tests that drive every pmbus subcommand handler against
the sandbox PMBus chip emulator:
dev (select by bus:addr and by regulator-name), list, info,
telemetry, status, dump, read, write, clear, vout, scan and help.
Tested using:
./u-boot -T -c "ut dm pmbus*"
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
MAINTAINERS | 1 +
test/dm/Makefile | 1 +
test/dm/pmbus.c | 247 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 249 insertions(+)
create mode 100644 test/dm/pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index bdfb660a743..ed0e31eac91 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1597,6 +1597,7 @@ F: drivers/power/regulator/sandbox_pmbus.c
F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
+F: test/dm/pmbus.c
POWER
M: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 0e3c63568dd..76aa1fff9ba 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_PINCONF) += pinmux.o
endif
obj-$(CONFIG_POWER_DOMAIN) += power-domain.o
obj-$(CONFIG_ACPI_PMC) += pmc.o
+obj-$(CONFIG_CMD_PMBUS) += pmbus.o
obj-$(CONFIG_DM_PMIC) += pmic.o
obj-$(CONFIG_DM_PWM) += pwm.o
obj-$(CONFIG_ARM_FFA_TRANSPORT) += ffa.o
diff --git a/test/dm/pmbus.c b/test/dm/pmbus.c
new file mode 100644
index 00000000000..48c8ee11c30
--- /dev/null
+++ b/test/dm/pmbus.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Unit tests for the PMBus 1.x framework, the generic
+ * PMBus regulator and the pmbus CLI command.
+ */
+
+#include <console.h>
+#include <dm.h>
+#include <i2c.h>
+#include <pmbus.h>
+#include <dm/test.h>
+#include <test/test.h>
+#include <test/ut.h>
+
+/* The line pmbus dev prints when a chip is selected */
+#define PMBUS_ACTIVE_LINE \
+ "pmbus: active i2c0:0x70 rail=\"sandbox-pmbus-vout\" " \
+ "MFR_ID=\"SANDBOX\" MODEL=\"PMBUS-EMUL\" vendor=(generic)"
+
+/* The line pmbus list prints for the bound chip */
+#define PMBUS_LIST_LINE \
+ " i2c0:0x70 rail=\"sandbox-pmbus-vout\" node=pmbus@70 " \
+ "driver=pmbus_generic_regulator"
+
+/* Select the emulated chip and check the resulting banner line */
+static int pmbus_select(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus dev 0:0x70", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ return 0;
+}
+
+/* The chip is reachable via UCLASS_REGULATOR (compatible = "pmbus") */
+static int dm_test_pmbus_bind(struct unit_test_state *uts)
+{
+ struct udevice *dev;
+
+ ut_assertok(uclass_get_device_by_name(UCLASS_REGULATOR, "pmbus@70",
+ &dev));
+ ut_asserteq_str("pmbus_generic_regulator", dev->driver->name);
+ ut_asserteq(UCLASS_I2C, device_get_uclass_id(dev_get_parent(dev)));
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_bind, UTF_SCAN_FDT);
+
+/* pmbus dev by <bus>:<addr> and by regulator-name select the chip */
+static int dm_test_pmbus_dev(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus dev 0:0x70", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ /* Selecting by DT regulator-name resolves to the same chip */
+ ut_assertok(run_command("pmbus dev sandbox-pmbus-vout", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ /* pmbus dev with no argument reprints the active chip */
+ ut_assertok(run_command("pmbus dev", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_dev, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus list enumerates the bound chip among the UCLASS_REGULATOR devices */
+static int dm_test_pmbus_list(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus list", 0));
+ ut_assert_skip_to_line(PMBUS_LIST_LINE);
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_list, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus info decodes identification + the detected driver_info */
+static int dm_test_pmbus_info(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus info", 0));
+ ut_assert_nextline("pmbus device i2c0:0x70");
+ ut_assert_nextline(" regulator-name: \"sandbox-pmbus-vout\"");
+ ut_assert_nextline(" MFR_ID : \"SANDBOX\"");
+ ut_assert_nextline(" MFR_MODEL : \"PMBUS-EMUL\"");
+ ut_assert_nextline(" MFR_REVISION : \"1.0\" raw=0x312e30");
+ ut_assert_nextline(" PMBUS_REVISION: 0x33 (PMBus 1.3)");
+ ut_assert_nextline(" vendor : (none)");
+ ut_assert_nextline(" driver_info : pages=1");
+ ut_assert_nextline(" [VOLTAGE_IN ] format=LINEAR");
+ ut_assert_nextline(" [VOLTAGE_OUT ] format=LINEAR");
+ ut_assert_nextline(" [CURRENT_IN ] format=LINEAR");
+ ut_assert_nextline(" [CURRENT_OUT ] format=LINEAR");
+ ut_assert_nextline(" [POWER ] format=LINEAR");
+ ut_assert_nextline(" [TEMPERATURE ] format=LINEAR");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_info, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/*
+ * pmbus telemetry decodes the implemented sensors and prints
+ * "(not supported)" for the commands the emulator NAKs (READ_IIN,
+ * READ_POUT). LINEAR11 is used for VIN/IOUT/TEMP, LINEAR16 (with the
+ * VOUT_MODE 2^-8 exponent) for VOUT.
+ */
+static int dm_test_pmbus_telemetry(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus telemetry", 0));
+ ut_assert_nextline("pmbus telemetry @ i2c0:0x70");
+ ut_assert_nextline(" VIN : raw=0x0abc 1400.000V");
+ ut_assert_nextline(" VOUT : raw=0x0200 2.000V");
+ ut_assert_nextline(" IIN : (not supported)");
+ ut_assert_nextline(" IOUT : raw=0x0123 291.000A");
+ ut_assert_nextline(" POUT : (not supported)");
+ ut_assert_nextline(" TEMP : raw=0x0019 25.000C");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_telemetry, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus status decodes every STATUS_* register; the emulator is clean */
+static int dm_test_pmbus_status(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus status", 0));
+ ut_assert_nextline("pmbus status @ i2c0:0x70");
+ ut_assert_nextline(" STATUS_WORD (79h) = 0x0000 [clean]");
+ ut_assert_nextline(" STATUS_VOUT (7Ah) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_IOUT (7Bh) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_INPUT (7Ch) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_TEMP (7Dh) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_CML (7Eh) = 0x00 [clean]");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_status, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus read/pmbus write raw register access (byte, word, string) */
+static int dm_test_pmbus_read_write(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ /* Symbolic and numeric register names both resolve */
+ ut_assertok(run_command("pmbus read VOUT_MODE", 0));
+ ut_assert_nextline(" 20h VOUT_MODE b=0x18");
+ ut_assertok(run_command("pmbus read 0x8b w", 0));
+ ut_assert_nextline(" 8bh READ_VOUT w=0x0200");
+ ut_assertok(run_command("pmbus read MFR_ID s", 0));
+ ut_assert_nextline(" 99h MFR_ID s=\"SANDBOX\"");
+
+ /* A word write is observable on the next read-back */
+ ut_assertok(run_command("pmbus write VOUT_COMMAND 0x0123 w", 0));
+ ut_assert_nextline("pmbus: wrote 0x123 to 21h (VOUT_COMMAND)");
+ ut_assertok(run_command("pmbus read VOUT_COMMAND w", 0));
+ ut_assert_nextline(" 21h VOUT_COMMAND w=0x0123");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_read_write, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus vout reads back VOUT via the active driver_info decoder */
+static int dm_test_pmbus_vout(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus vout", 0));
+ ut_assert_nextline("pmbus VOUT @ i2c0:0x70 raw=0x0200 2.000V");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_vout, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus dump walks every standard register; spot-check one line */
+static int dm_test_pmbus_dump(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus dump", 0));
+ ut_assert_nextline("pmbus dump @ i2c0:0x70 (registers known to <pmbus.h>)");
+ ut_assert_skip_to_line(" 20h VOUT_MODE b=0x18");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_dump, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus clear [faults] issues CLEAR_FAULTS (03h) */
+static int dm_test_pmbus_clear(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus clear faults", 0));
+ ut_assert_nextline("pmbus: CLEAR_FAULTS (03h) issued (RAM sticky STATUS_* cleared)");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_clear, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus scan finds the emulated chip by its MFR_ID block read */
+static int dm_test_pmbus_scan(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus scan 0", 0));
+ ut_assert_skip_to_line(" i2c0:0x70 MFR_ID=\"SANDBOX\"");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_scan, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus help lists vendor extensions; none are registered here */
+static int dm_test_pmbus_help(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus help", 0));
+ ut_assert_nextline("pmbus: no vendor extensions registered.");
+ ut_assert_skip_to_line(" board hook (boot snapshot) and re run 'pmbus help'.");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_help, UTF_SCAN_FDT | UTF_CONSOLE);
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support
[not found] <"<20260702171618.1773206-1-vjardin@free.fr>
@ 2026-07-02 19:56 ` Vincent Jardin
2026-07-02 19:56 ` [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
` (6 more replies)
0 siblings, 7 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 19:56 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Alexey Charkov, Alice Guo, Andrew Goodbody,
Anshul Dalal, Bo-Chen Chen, David Lechner, Dinesh Maniyam,
Fabio Estevam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jaehoon Chung,
Jerome Forissier, Julien Masson, Julien Stephan, Kory Maincent,
Kuan-Wei Chiu, Lucien.Jheng, Macpaul Lin, Marek Vasut,
Markus Schneider-Pargmann (TI.com), Martin Schwan,
Mateusz Furdyna, Mattijs Korpershoek, Michael Trimarchi,
Michal Simek, Mikhail Kshevetskiy, NXP i.MX U-Boot Team,
Neil Armstrong, Peng Fan, Peter Robinson, Philip Molloy,
Pieter Van Trappen, Quentin Schulz, Rasmus Villemoes, Raymond Mao,
Simon Glass, Stefan Roese, Stefano Babic, Svyatoslav Ryhel,
Tom Rini
This series adds U-Boot's PMBus 1.x support as a small boot-time
layer (not a hwmon clone):
- a decoder + transport library and the pmbus CLI command
- a shared UCLASS_REGULATOR adapter plus a catch-all driver for
compliant chips, add the MPS MPQ8785 per-chip driver
- a generic PMBus die-temperature UCLASS_THERMAL bridge
- migration of the shared NXP VID rail-trim code to this framework
- a sandbox PMBus chip emulator and "ut dm pmbus" unit tests that
exercise most subcommand of the CLI.
The goal is to identify PMBus regulators at boot, print telemetry and
decode chip alerts before the kernel takes over - no polling, no
sysfs, no fan loops. Linux owns the runtime side.
Changes in v2:
- Apply Tom Rini's v1 review: drop the local DT binding YAML files
Vincent Jardin (7):
pmbus: add PMBus 1.x framework, CLI, and binding
power: regulator: add generic PMBus UCLASS_REGULATOR adapter
power: regulator: add MPS MPQ8785 PMBus regulator driver
board: nxp: vid: introduce PMBus framework support
thermal: pmbus: add PMBus die-temp driver
test: dm: pmbus: add a sandbox PMBus chip emulator
test: dm: pmbus: test pmbus command and framework
MAINTAINERS | 15 +
arch/Kconfig.nxp | 4 +
arch/sandbox/dts/test.dts | 10 +
board/nxp/common/vid.c | 104 +--
board/nxp/common/vid.h | 15 +-
cmd/Kconfig | 14 +
cmd/Makefile | 1 +
cmd/pmbus.c | 816 ++++++++++++++++++++++
configs/sandbox_defconfig | 6 +
doc/develop/index.rst | 1 +
doc/develop/pmbus.rst | 633 +++++++++++++++++
drivers/power/regulator/Kconfig | 43 ++
drivers/power/regulator/Makefile | 4 +
drivers/power/regulator/mpq8785.c | 494 +++++++++++++
drivers/power/regulator/pmbus_generic.c | 90 +++
drivers/power/regulator/pmbus_helper.c | 315 +++++++++
drivers/power/regulator/pmbus_helper.h | 90 +++
drivers/power/regulator/sandbox_pmbus.c | 160 +++++
drivers/thermal/Kconfig | 8 +
drivers/thermal/Makefile | 1 +
drivers/thermal/pmbus_thermal.c | 33 +
include/pmbus.h | 666 ++++++++++++++++++
lib/Kconfig | 16 +
lib/Makefile | 1 +
lib/pmbus.c | 876 ++++++++++++++++++++++++
test/dm/Makefile | 1 +
test/dm/pmbus.c | 247 +++++++
27 files changed, 4609 insertions(+), 55 deletions(-)
create mode 100644 cmd/pmbus.c
create mode 100644 doc/develop/pmbus.rst
create mode 100644 drivers/power/regulator/mpq8785.c
create mode 100644 drivers/power/regulator/pmbus_generic.c
create mode 100644 drivers/power/regulator/pmbus_helper.c
create mode 100644 drivers/power/regulator/pmbus_helper.h
create mode 100644 drivers/power/regulator/sandbox_pmbus.c
create mode 100644 drivers/thermal/pmbus_thermal.c
create mode 100644 include/pmbus.h
create mode 100644 lib/pmbus.c
create mode 100644 test/dm/pmbus.c
--
2.43.0
base-commit: f605dcee103c897b6f1a8873549a36949bd4e2a1
branch: for-upstream/pmbus-v5
^ permalink raw reply [flat|nested] 24+ messages in thread
* [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
@ 2026-07-02 19:56 ` Vincent Jardin
2026-07-06 3:37 ` Peng Fan
2026-07-02 20:07 ` [PATCH v2 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
` (5 subsequent siblings)
6 siblings, 1 reply; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 19:56 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Alexey Charkov, Andrew Goodbody, David Lechner,
Dinesh Maniyam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jerome Forissier,
Julien Stephan, Kory Maincent, Kuan-Wei Chiu, Marek Vasut,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
Neil Armstrong, Peng Fan, Peter Robinson, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
Add U-Boot's PMBus 1.x layer: the decoder/transport library, the
pmbus CLI command and a generic DT binding.
The subsequent commits provide the UCLASS_REGULATOR adapter and per-chip
drivers.
U-Boot's PMBus support is not a hwmon clone of Linux's
drivers/hwmon/pmbus/. Linux owns the runtime side (polling, sysfs,
alert IRQs, fan loops). U-Boot owns the boot-time side in order to,
- identify the PMBus regulators a board carries: MFR_ID/
MFR_MODEL/MFR_REVISION + sanity checks.
- print telemetry (VIN/VOUT/IIN/IOUT/POUT/TEMP) so an
operator can confirm rail voltages and faults before the kernel
- decode any chip alerts (STATUS_VOUT/STATUS_IOUT/STATUS_INPUT/
STATUS_TEMPERATURE/STATUS_CML) so a boot log shows why the
previous boot failed or the board had been power cycled because
of an outage (typically over temperature or under current).
Out of scope by design: no periodic polling, no sysfs, no fan-speed
control loop, no PMBUS_VIRT_* sensor virtualisation, no caching.
If a use case needs any of those, the answer should be "wait until
Linux comes up". It shall remain a thin layer.
The constants and structural shape (command codes, status bit names,
sensor-class enum, format enum, struct pmbus_driver_info) are
mirrored from Linux drivers/hwmon/pmbus/pmbus.h verbatim. The
decoders/encoders are reimplemented from the PMBus 1.3
specification because the surrounding hwmon context (struct
pmbus_data, sysfs caching, hwmon publication) does not apply.
The main benefits:
- One framework + CLI for any board carrying PMBus regulators:
no per-board PMBus implementation required anymore.
- Boards call pmbus_print_telemetry() / pmbus_print_status_word()
directly from boot init for a snapshot, sharing all decode +
format-dispatch with the CLI.
- Linux-compatible constants and DT binding so porting an existing
drivers/hwmon/pmbus/ chip is mechanical.
- Boot-time AVS/VID rail trim reuses the same decoders and
encoders as the CLI and the regulator path: no duplicate math.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
Changes in v2:
- Apply Tom Rini's v1 review: drop the local DT binding YAML files
MAINTAINERS | 8 +
cmd/Kconfig | 14 +
cmd/Makefile | 1 +
cmd/pmbus.c | 816 +++++++++++++++++++++++++++++++++++++++
doc/develop/index.rst | 1 +
doc/develop/pmbus.rst | 633 +++++++++++++++++++++++++++++++
include/pmbus.h | 629 +++++++++++++++++++++++++++++++
lib/Kconfig | 16 +
lib/Makefile | 1 +
lib/pmbus.c | 859 ++++++++++++++++++++++++++++++++++++++++++
10 files changed, 2978 insertions(+)
create mode 100644 cmd/pmbus.c
create mode 100644 doc/develop/pmbus.rst
create mode 100644 include/pmbus.h
create mode 100644 lib/pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 571af196465..39e333f8f70 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1580,6 +1580,14 @@ S: Maintained
F: cmd/pci_mps.c
F: test/cmd/pci_mps.c
+PMBUS
+M: Vincent Jardin <vjardin@free.fr>
+S: Maintained
+F: cmd/pmbus.c
+F: doc/develop/pmbus.rst
+F: include/pmbus.h
+F: lib/pmbus.c
+
POWER
M: Jaehoon Chung <jh80.chung@samsung.com>
M: Peng Fan <peng.fan@nxp.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index c71c6824a19..63f783ac0b9 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -2715,6 +2715,20 @@ config CMD_PMIC
- pmic write address - write byte to register at address
The only one change for this command is 'dev' subcommand.
+config CMD_PMBUS
+ bool "pmbus device interrogation and control command"
+ depends on PMBUS
+ help
+ Enable the pmbus U-Boot CLI command. Provides identification,
+ decoded telemetry, STATUS_* decoding, raw register read/write,
+ CLEAR_FAULTS, and VOUT_COMMAND set/get against any PMBus 1.x
+ compliant device selectable via 'pmbus dev <bus>:<addr>'.
+
+ Per chip drivers and board files publish vendor extensions in
+ the 'pmbus <vendor> ...' namespace.
+
+ See doc/develop/pmbus.rst for the full usage reference.
+
config CMD_REGULATOR
bool "Enable Driver Model REGULATOR command"
depends on DM_REGULATOR
diff --git a/cmd/Makefile b/cmd/Makefile
index bbbdfcc4ded..ce772e5555b 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -228,6 +228,7 @@ obj-$(CONFIG_CMD_AXI) += axi.o
obj-$(CONFIG_CMD_PVBLOCK) += pvblock.o
# Power
+obj-$(CONFIG_CMD_PMBUS) += pmbus.o
obj-$(CONFIG_CMD_PMIC) += pmic.o
obj-$(CONFIG_CMD_REGULATOR) += regulator.o
diff --git a/cmd/pmbus.c b/cmd/pmbus.c
new file mode 100644
index 00000000000..5ddaf3665fc
--- /dev/null
+++ b/cmd/pmbus.c
@@ -0,0 +1,816 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * pmbus U-Boot CLI command.
+ *
+ * Generic command surface over the PMBus 1.x framework defined in
+ * <pmbus.h> + lib/pmbus.c.
+ *
+ * See doc/develop/pmbus.rst for the full usage reference.
+ */
+
+#include <command.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/ctype.h>
+#include <power/regulator.h>
+
+static int parse_bus_addr(const char *s, int *bus_seq, u8 *addr)
+{
+ char busbuf[8];
+ const char *colon;
+ unsigned long b, a;
+ size_t buslen;
+
+ colon = strchr(s, ':');
+ if (!colon)
+ return -EINVAL;
+ buslen = colon - s;
+ if (buslen == 0 || buslen >= sizeof(busbuf))
+ return -EINVAL;
+ memcpy(busbuf, s, buslen);
+ busbuf[buslen] = '\0';
+ if (strict_strtoul(busbuf, 0, &b))
+ return -EINVAL;
+ if (strict_strtoul(colon + 1, 0, &a) || a > 0x7f)
+ return -EINVAL;
+ *bus_seq = (int)b;
+ *addr = (u8)a;
+ return 0;
+}
+
+static const struct {
+ const char *name;
+ u8 reg;
+} pmbus_reg_syms[] = {
+ { "PAGE", PMBUS_PAGE },
+ { "OPERATION", PMBUS_OPERATION },
+ { "ON_OFF_CONFIG", PMBUS_ON_OFF_CONFIG },
+ { "CLEAR_FAULTS", PMBUS_CLEAR_FAULTS },
+ { "WRITE_PROTECT", PMBUS_WRITE_PROTECT },
+ { "CAPABILITY", PMBUS_CAPABILITY },
+ { "VOUT_MODE", PMBUS_VOUT_MODE },
+ { "VOUT_COMMAND", PMBUS_VOUT_COMMAND },
+ { "VOUT_TRIM", PMBUS_VOUT_TRIM },
+ { "VOUT_MAX", PMBUS_VOUT_MAX },
+ { "VOUT_SCALE_LOOP", PMBUS_VOUT_SCALE_LOOP },
+ { "STATUS_BYTE", PMBUS_STATUS_BYTE },
+ { "STATUS_WORD", PMBUS_STATUS_WORD },
+ { "STATUS_VOUT", PMBUS_STATUS_VOUT },
+ { "STATUS_IOUT", PMBUS_STATUS_IOUT },
+ { "STATUS_INPUT", PMBUS_STATUS_INPUT },
+ { "STATUS_TEMP", PMBUS_STATUS_TEMPERATURE },
+ { "STATUS_CML", PMBUS_STATUS_CML },
+ { "READ_VIN", PMBUS_READ_VIN },
+ { "READ_IIN", PMBUS_READ_IIN },
+ { "READ_VOUT", PMBUS_READ_VOUT },
+ { "READ_IOUT", PMBUS_READ_IOUT },
+ { "READ_TEMP1", PMBUS_READ_TEMPERATURE_1 },
+ { "READ_TEMP2", PMBUS_READ_TEMPERATURE_2 },
+ { "READ_TEMP3", PMBUS_READ_TEMPERATURE_3 },
+ { "READ_DUTY", PMBUS_READ_DUTY_CYCLE },
+ { "READ_FREQ", PMBUS_READ_FREQUENCY },
+ { "READ_POUT", PMBUS_READ_POUT },
+ { "READ_PIN", PMBUS_READ_PIN },
+ { "REVISION", PMBUS_REVISION },
+ { "MFR_ID", PMBUS_MFR_ID },
+ { "MFR_MODEL", PMBUS_MFR_MODEL },
+ { "MFR_REVISION", PMBUS_MFR_REVISION },
+};
+
+static int parse_reg(const char *s, u8 *reg)
+{
+ unsigned long v;
+ unsigned int i;
+
+ if (isdigit((unsigned char)s[0])) {
+ if (strict_strtoul(s, 0, &v) || v > 0xff)
+ return -EINVAL;
+ *reg = (u8)v;
+ return 0;
+ }
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++) {
+ if (!strcasecmp(s, pmbus_reg_syms[i].name)) {
+ *reg = pmbus_reg_syms[i].reg;
+ return 0;
+ }
+ }
+ return -EINVAL;
+}
+
+static const char *pmbus_reg_name(u8 reg)
+{
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++)
+ if (pmbus_reg_syms[i].reg == reg)
+ return pmbus_reg_syms[i].name;
+ return "?";
+}
+
+static int require_active(struct udevice **chip,
+ const struct pmbus_active_dev **act)
+{
+ *act = pmbus_active();
+ if (!*act) {
+ printf("pmbus: no active device. Use 'pmbus dev <bus>:<addr>' first.\n");
+ return CMD_RET_FAILURE;
+ }
+ if (pmbus_active_get_i2c(chip)) {
+ printf("pmbus: cannot reach i2c%d:0x%02x\n",
+ (*act)->bus_seq, (*act)->addr);
+ return CMD_RET_FAILURE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static void print_micro(s64 micro, const char *unit)
+{
+ s64 abs_milli;
+
+ abs_milli = (micro < 0 ? -micro : micro) / 1000LL;
+ printf("%lld.%03lld%s",
+ (long long)(micro / 1000000LL),
+ (long long)(abs_milli % 1000LL), unit);
+}
+
+static void print_active(const struct pmbus_active_dev *act)
+{
+ printf("pmbus: active i2c%d:0x%02x", act->bus_seq, act->addr);
+ if (act->name[0])
+ printf(" rail=\"%s\"", act->name);
+ printf(" MFR_ID=\"%s\" MODEL=\"%s\" vendor=%s%s\n",
+ act->mfr_id[0] ? act->mfr_id : "?",
+ act->mfr_model[0] ? act->mfr_model : "?",
+ act->vendor[0] ? act->vendor : "(generic)",
+ act->info ? "" : " [no driver_info]");
+}
+
+static int do_dev(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ int bus_seq, ret;
+ u8 addr;
+
+ if (argc < 2) {
+ act = pmbus_active();
+ if (!act) {
+ printf("pmbus: no active device\n");
+ return CMD_RET_SUCCESS;
+ }
+ print_active(act);
+ return CMD_RET_SUCCESS;
+ }
+
+ if (parse_bus_addr(argv[1], &bus_seq, &addr) < 0) {
+ ret = pmbus_resolve_by_name(argv[1], &bus_seq, &addr);
+ if (ret) {
+ printf("pmbus: '%s' is neither <bus>:<addr> nor a known regulator-name (%d)\n",
+ argv[1], ret);
+ return CMD_RET_FAILURE;
+ }
+ }
+ ret = pmbus_set_active(bus_seq, addr);
+ if (ret) {
+ printf("pmbus: cannot select i2c%d:0x%02x (%d)\n",
+ bus_seq, addr, ret);
+ return CMD_RET_FAILURE;
+ }
+ act = pmbus_active();
+ if (act)
+ print_active(act);
+ return CMD_RET_SUCCESS;
+}
+
+static int do_list(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ struct udevice *dev;
+ struct uclass *uc;
+ int ret, n = 0;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR)) {
+ printf("pmbus: CONFIG_DM_REGULATOR not enabled in this build. Use 'pmbus dev <bus>:<addr>'.\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ ret = uclass_get(UCLASS_REGULATOR, &uc);
+ if (ret) {
+ printf("pmbus: UCLASS_REGULATOR not available\n");
+ return CMD_RET_SUCCESS;
+ }
+ uclass_foreach_dev(dev, uc) {
+ struct dm_regulator_uclass_plat *up = dev_get_uclass_plat(dev);
+ struct udevice *parent = dev_get_parent(dev);
+ const char *rname = (up && up->name) ? up->name : "";
+ const char *drv = (dev->driver && dev->driver->name)
+ ? dev->driver->name : "?";
+ int bus_seq = -1;
+ int addr = -1;
+
+ if (parent && device_get_uclass_id(parent) == UCLASS_I2C) {
+ bus_seq = dev_seq(parent);
+ addr = dev_read_addr(dev);
+ }
+
+ if (n == 0)
+ printf("UCLASS_REGULATOR devices (no PMBus filter):\n");
+ if (bus_seq >= 0 && addr >= 0) {
+ printf(" i2c%d:0x%02x rail=\"%s\" node=%s driver=%s\n",
+ bus_seq, addr, rname, dev->name, drv);
+ } else {
+ printf(" (non-I2C) rail=\"%s\" node=%s driver=%s\n",
+ rname, dev->name, drv);
+ }
+ n++;
+ }
+ if (!n)
+ printf("pmbus: no UCLASS_REGULATOR devices bound. Use 'pmbus dev <bus>:<addr>' to select a chip directly.\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_info(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ static const char * const cls_names[PSC_NUM_CLASSES] = {
+ "VOLTAGE_IN", "VOLTAGE_OUT", "CURRENT_IN", "CURRENT_OUT",
+ "POWER", "TEMPERATURE",
+ };
+ static const char * const fmt_names[] = {
+ "LINEAR", "IEEE754", "DIRECT", "VID",
+ };
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc, c, rrev;
+ u8 rev = 0;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ rrev = pmbus_read_byte(chip, PMBUS_REVISION, &rev);
+
+ printf("pmbus device i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ if (act->name[0])
+ printf(" regulator-name: \"%s\"\n", act->name);
+ printf(" MFR_ID : \"%s\"\n", act->mfr_id[0] ? act->mfr_id : "?");
+ printf(" MFR_MODEL : \"%s\"\n", act->mfr_model[0] ? act->mfr_model : "?");
+
+ /*
+ * MFR_REVISION may encodes the revision as a non printable byte
+ * (BCD nibbles, packed major / minor, etc.). Show both the
+ * printable form and the raw bytes the chip returned.
+ */
+ {
+ u8 raw[PMBUS_MFR_STRING_MAX];
+ int len, i;
+
+ if (dm_i2c_read(chip, PMBUS_MFR_REVISION, raw, 1) ||
+ raw[0] < 1 || raw[0] > sizeof(raw) - 1 ||
+ dm_i2c_read(chip, PMBUS_MFR_REVISION, raw, raw[0] + 1)) {
+ printf(" MFR_REVISION : \"%s\"\n",
+ act->mfr_revision[0] ? act->mfr_revision : "?");
+ } else {
+ len = raw[0];
+ printf(" MFR_REVISION : \"%s\" raw=0x",
+ act->mfr_revision[0] ? act->mfr_revision : "?");
+ for (i = 1; i <= len; i++)
+ printf("%02x", raw[i]);
+ printf("\n");
+ }
+ }
+
+ if (rrev)
+ printf(" PMBUS_REVISION: <read failed (%d)>\n", rrev);
+ else
+ printf(" PMBUS_REVISION: 0x%02x (%s)\n", rev,
+ rev == PMBUS_REV_13 ? "PMBus 1.3" :
+ rev == PMBUS_REV_12 ? "PMBus 1.2" :
+ rev == PMBUS_REV_11 ? "PMBus 1.1" :
+ rev == PMBUS_REV_10 ? "PMBus 1.0" : "unknown");
+ printf(" vendor : %s\n", act->vendor[0] ? act->vendor : "(none)");
+
+ if (!act->info) {
+ printf(" driver_info : not registered (decoders fall back to LINEAR16 / LINEAR11)\n");
+ return CMD_RET_SUCCESS;
+ }
+ printf(" driver_info : pages=%d\n", act->info->pages);
+ for (c = 0; c < PSC_NUM_CLASSES; c++) {
+ printf(" [%-12s] format=%s",
+ cls_names[c], fmt_names[act->info->format[c]]);
+ if (act->info->format[c] == pmbus_fmt_direct)
+ printf(", m=%d, b=%d, R=%d",
+ act->info->m[c], act->info->b[c], act->info->R[c]);
+ printf("\n");
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_telemetry(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ printf("pmbus telemetry @ i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ pmbus_print_telemetry(chip);
+ return CMD_RET_SUCCESS;
+}
+
+static int do_status(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ u16 word = 0;
+ u8 b;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ if (pmbus_read_word(chip, PMBUS_STATUS_WORD, &word)) {
+ printf("pmbus: STATUS_WORD read failed\n");
+ return CMD_RET_FAILURE;
+ }
+
+ const struct pmbus_status_override *ovr =
+ act->info ? act->info->status_overrides : NULL;
+
+ printf("pmbus status @ i2c%d:0x%02x\n", act->bus_seq, act->addr);
+ printf(" STATUS_WORD (79h) = 0x%04x [", word);
+ pmbus_print_status_bits(PMBUS_STATUS_WORD, word,
+ pmbus_status_word_bits, ovr);
+ printf("]\n");
+
+ if (pmbus_read_byte(chip, PMBUS_STATUS_VOUT, &b) == 0) {
+ printf(" STATUS_VOUT (7Ah) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_VOUT, b,
+ pmbus_status_vout_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_IOUT, &b) == 0) {
+ printf(" STATUS_IOUT (7Bh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_IOUT, b,
+ pmbus_status_iout_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_INPUT, &b) == 0) {
+ printf(" STATUS_INPUT (7Ch) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_INPUT, b,
+ pmbus_status_input_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_TEMPERATURE, &b) == 0) {
+ printf(" STATUS_TEMP (7Dh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_TEMPERATURE, b,
+ pmbus_status_temp_bits, ovr);
+ printf("]\n");
+ }
+ if (pmbus_read_byte(chip, PMBUS_STATUS_CML, &b) == 0) {
+ printf(" STATUS_CML (7Eh) = 0x%02x [", b);
+ pmbus_print_status_bits(PMBUS_STATUS_CML, b,
+ pmbus_status_cml_bits, ovr);
+ printf("]\n");
+ }
+
+ return CMD_RET_SUCCESS;
+}
+
+static int do_dump(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ unsigned int i;
+ int rc;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ printf("pmbus dump @ i2c%d:0x%02x (registers known to <pmbus.h>)\n",
+ act->bus_seq, act->addr);
+ for (i = 0; i < ARRAY_SIZE(pmbus_reg_syms); i++) {
+ u8 reg = pmbus_reg_syms[i].reg;
+ u8 b = 0;
+ u16 w = 0;
+
+ switch (reg) {
+ case PMBUS_PAGE:
+ case PMBUS_OPERATION:
+ case PMBUS_ON_OFF_CONFIG:
+ case PMBUS_WRITE_PROTECT:
+ case PMBUS_CAPABILITY:
+ case PMBUS_VOUT_MODE:
+ case PMBUS_STATUS_BYTE:
+ case PMBUS_STATUS_VOUT:
+ case PMBUS_STATUS_IOUT:
+ case PMBUS_STATUS_INPUT:
+ case PMBUS_STATUS_TEMPERATURE:
+ case PMBUS_STATUS_CML:
+ case PMBUS_REVISION:
+ if (pmbus_read_byte(chip, reg, &b) == 0)
+ printf(" %02xh %-15s b=0x%02x\n",
+ reg, pmbus_reg_syms[i].name, b);
+ break;
+ case PMBUS_MFR_ID:
+ case PMBUS_MFR_MODEL:
+ case PMBUS_MFR_REVISION: {
+ char s[PMBUS_MFR_STRING_MAX];
+
+ if (pmbus_read_string(chip, reg, s, sizeof(s),
+ act->info ? false : false) >= 0)
+ printf(" %02xh %-15s s=\"%s\"\n",
+ reg, pmbus_reg_syms[i].name, s);
+ break;
+ }
+ default:
+ if (pmbus_read_word(chip, reg, &w) == 0)
+ printf(" %02xh %-15s w=0x%04x\n",
+ reg, pmbus_reg_syms[i].name, w);
+ break;
+ }
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_read(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ const char *fmt = "b";
+ u8 reg, b;
+ u16 w;
+ char s[PMBUS_MFR_STRING_MAX];
+ int rc, ret;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ if (parse_reg(argv[1], ®) < 0) {
+ printf("pmbus: invalid register '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ if (argc >= 3)
+ fmt = argv[2];
+
+ if (!strcmp(fmt, "b")) {
+ ret = pmbus_read_byte(chip, reg, &b);
+ if (ret) {
+ printf("pmbus: read byte 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s b=0x%02x\n", reg, pmbus_reg_name(reg), b);
+ } else if (!strcmp(fmt, "w")) {
+ ret = pmbus_read_word(chip, reg, &w);
+ if (ret) {
+ printf("pmbus: read word 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s w=0x%04x\n", reg, pmbus_reg_name(reg), w);
+ } else if (!strcmp(fmt, "s")) {
+ ret = pmbus_read_string(chip, reg, s, sizeof(s), false);
+ if (ret < 0) {
+ printf("pmbus: read string 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf(" %02xh %-15s s=\"%s\"\n", reg, pmbus_reg_name(reg), s);
+ } else {
+ printf("pmbus: unknown format '%s' (expected b, w, or s)\n", fmt);
+ return CMD_RET_USAGE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int do_write(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ const char *fmt = "b";
+ unsigned long val;
+ u8 reg, b;
+ u8 buf[2];
+ int rc, ret;
+
+ if (argc < 3)
+ return CMD_RET_USAGE;
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ if (parse_reg(argv[1], ®) < 0) {
+ printf("pmbus: invalid register '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ if (strict_strtoul(argv[2], 0, &val)) {
+ printf("pmbus: invalid value '%s'\n", argv[2]);
+ return CMD_RET_USAGE;
+ }
+ if (argc >= 4)
+ fmt = argv[3];
+
+ if (!strcmp(fmt, "b")) {
+ if (val > 0xff) {
+ printf("pmbus: byte value out of range\n");
+ return CMD_RET_USAGE;
+ }
+ b = (u8)val;
+ ret = dm_i2c_write(chip, reg, &b, 1);
+ } else if (!strcmp(fmt, "w")) {
+ if (val > 0xffff) {
+ printf("pmbus: word value out of range\n");
+ return CMD_RET_USAGE;
+ }
+ buf[0] = (u8)(val & 0xff);
+ buf[1] = (u8)((val >> 8) & 0xff);
+ ret = dm_i2c_write(chip, reg, buf, 2);
+ } else {
+ printf("pmbus: unknown format '%s' (expected b or w)\n", fmt);
+ return CMD_RET_USAGE;
+ }
+ if (ret) {
+ printf("pmbus: write 0x%02x failed (%d)\n", reg, ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: wrote 0x%lx to %02xh (%s)\n", val, reg, pmbus_reg_name(reg));
+ return CMD_RET_SUCCESS;
+}
+
+static int do_clear(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ int rc, ret;
+
+ if (argc >= 2 && strcmp(argv[1], "faults") != 0) {
+ printf("pmbus: unknown clear subcommand '%s' (expected 'faults')\n",
+ argv[1]);
+ return CMD_RET_USAGE;
+ }
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+ ret = pmbus_clear_faults(chip);
+ if (ret) {
+ printf("pmbus: CLEAR_FAULTS (03h) failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: CLEAR_FAULTS (03h) issued (RAM sticky STATUS_* cleared)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_vout(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_active_dev *act;
+ struct udevice *chip;
+ u8 vout_mode = 0;
+ u16 raw;
+ s64 uv;
+ int rc, ret;
+
+ rc = require_active(&chip, &act);
+ if (rc)
+ return rc;
+
+ if (pmbus_read_byte(chip, PMBUS_VOUT_MODE, &vout_mode)) {
+ printf("pmbus: VOUT_MODE read failed\n");
+ return CMD_RET_FAILURE;
+ }
+
+ if (argc < 2) {
+ if (pmbus_read_word(chip, PMBUS_READ_VOUT, &raw)) {
+ printf("pmbus: READ_VOUT failed\n");
+ return CMD_RET_FAILURE;
+ }
+ if (act->info)
+ uv = pmbus_reg2data(act->info, PSC_VOLTAGE_OUT, raw, vout_mode);
+ else
+ uv = pmbus_reg2data_linear16(raw, vout_mode);
+ printf("pmbus VOUT @ i2c%d:0x%02x raw=0x%04x ",
+ act->bus_seq, act->addr, raw);
+ print_micro(uv, "V");
+ printf("\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ {
+ unsigned long target_uv;
+ const char *fmt_name;
+ u8 buf[2];
+
+ if (strict_strtoul(argv[1], 0, &target_uv)) {
+ printf("pmbus: invalid microvolt value '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ raw = pmbus_data2reg_linear16((s64)target_uv, vout_mode);
+ fmt_name = "LINEAR16";
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ if (!act->info ||
+ act->info->format[PSC_VOLTAGE_OUT] != pmbus_fmt_direct) {
+ printf("pmbus: VOUT_MODE selects DIRECT but the active driver_info has no DIRECT coefficients for VOLTAGE_OUT\n");
+ return CMD_RET_FAILURE;
+ }
+ raw = pmbus_data2reg_direct((s64)target_uv,
+ act->info->m[PSC_VOLTAGE_OUT],
+ act->info->b[PSC_VOLTAGE_OUT],
+ act->info->R[PSC_VOLTAGE_OUT]);
+ fmt_name = "DIRECT";
+ break;
+ default:
+ printf("pmbus: VOUT_MODE 0x%02x selects an encoder not yet implemented (VID / IEEE754)\n",
+ vout_mode);
+ return CMD_RET_FAILURE;
+ }
+
+ buf[0] = raw & 0xff;
+ buf[1] = (raw >> 8) & 0xff;
+ ret = dm_i2c_write(chip, PMBUS_VOUT_COMMAND, buf, 2);
+ if (ret) {
+ printf("pmbus: VOUT_COMMAND write failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus: VOUT_COMMAND <- 0x%04x (%s, target %lu uV)\n",
+ raw, fmt_name, target_uv);
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int pmbus_scan_one_bus(struct udevice *bus, int bus_seq)
+{
+ int hits = 0;
+ int addr;
+
+ for (addr = 0x08; addr <= 0x77; addr++) {
+ struct udevice *chip;
+ u8 b;
+
+ if (i2c_get_chip(bus, addr, 1, &chip))
+ continue;
+ /* MFR_ID block read: 1st byte is the length of the string. */
+ if (dm_i2c_read(chip, PMBUS_MFR_ID, &b, 1))
+ continue;
+ if (b >= 1 && b <= PMBUS_MFR_STRING_MAX - 1) {
+ char s[PMBUS_MFR_STRING_MAX] = "";
+
+ pmbus_read_string(chip, PMBUS_MFR_ID, s, sizeof(s), false);
+ if (!s[0])
+ pmbus_read_string(chip, PMBUS_MFR_ID, s, sizeof(s), true);
+ printf(" i2c%d:0x%02x MFR_ID=\"%s\"\n",
+ bus_seq, addr, s[0] ? s : "(unprintable)");
+ hits++;
+ }
+ }
+ return hits;
+}
+
+static int do_scan(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ int total = 0;
+
+ if (argc >= 2) {
+ struct udevice *bus;
+ unsigned long val;
+ int bus_seq;
+
+ if (strict_strtoul(argv[1], 0, &val)) {
+ printf("pmbus: invalid bus seq '%s'\n", argv[1]);
+ return CMD_RET_USAGE;
+ }
+ bus_seq = (int)val;
+ if (uclass_get_device_by_seq(UCLASS_I2C, bus_seq, &bus)) {
+ printf("pmbus: i2c%d not available\n", bus_seq);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus scan i2c%d:\n", bus_seq);
+ total = pmbus_scan_one_bus(bus, bus_seq);
+ } else {
+ struct uclass *uc;
+ struct udevice *bus;
+
+ if (uclass_get(UCLASS_I2C, &uc))
+ return CMD_RET_FAILURE;
+ uclass_foreach_dev(bus, uc) {
+ int seq = dev_seq(bus);
+
+ if (seq < 0)
+ continue;
+ printf("pmbus scan i2c%d:\n", seq);
+ total += pmbus_scan_one_bus(bus, seq);
+ }
+ }
+ if (!total)
+ printf("pmbus: no PMBus responders found\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int do_help(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ unsigned int i, n = pmbus_vendor_count();
+
+ if (n == 0) {
+ printf("pmbus: no vendor extensions registered.\n");
+ printf(" Vendor handlers are registered by per chip drivers at\n");
+ printf(" probe time; trigger a probe via 'pmbus dev <name>' or a\n");
+ printf(" board hook (boot snapshot) and re run 'pmbus help'.\n");
+ return CMD_RET_SUCCESS;
+ }
+
+ printf("Registered pmbus vendor extensions (%u):\n\n", n);
+ for (i = 0; i < n; i++) {
+ const struct pmbus_vendor_op *op = pmbus_vendor_at(i);
+
+ if (!op)
+ continue;
+ printf("[vendor: %s]\n", op->vendor);
+ if (op->help)
+ printf("%s", op->help);
+ printf("\n");
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static struct cmd_tbl pmbus_subcmd[] = {
+ U_BOOT_CMD_MKENT(dev, 2, 1, do_dev, "", ""),
+ U_BOOT_CMD_MKENT(list, 1, 1, do_list, "", ""),
+ U_BOOT_CMD_MKENT(info, 1, 1, do_info, "", ""),
+ U_BOOT_CMD_MKENT(telemetry, 1, 1, do_telemetry, "", ""),
+ U_BOOT_CMD_MKENT(status, 1, 1, do_status, "", ""),
+ U_BOOT_CMD_MKENT(dump, 1, 1, do_dump, "", ""),
+ U_BOOT_CMD_MKENT(read, 3, 1, do_read, "", ""),
+ U_BOOT_CMD_MKENT(write, 4, 1, do_write, "", ""),
+ U_BOOT_CMD_MKENT(clear, 2, 1, do_clear, "", ""),
+ U_BOOT_CMD_MKENT(vout, 2, 1, do_vout, "", ""),
+ U_BOOT_CMD_MKENT(scan, 2, 1, do_scan, "", ""),
+ U_BOOT_CMD_MKENT(help, 1, 1, do_help, "", ""),
+};
+
+static int do_pmbus(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ const struct pmbus_vendor_op *vop;
+ struct cmd_tbl *cmd;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+
+ argc--;
+ argv++;
+
+ cmd = find_cmd_tbl(argv[0], pmbus_subcmd, ARRAY_SIZE(pmbus_subcmd));
+ if (cmd) {
+ if (argc > cmd->maxargs)
+ return CMD_RET_USAGE;
+ return cmd->cmd(cmdtp, flag, argc, argv);
+ }
+
+ /* Vendor namespace dispatch */
+ vop = pmbus_lookup_vendor(argv[0]);
+ if (vop)
+ return vop->handler(cmdtp, flag, argc, argv);
+
+ printf("pmbus: unknown subcommand '%s'\n", argv[0]);
+ return CMD_RET_USAGE;
+}
+
+U_BOOT_CMD(pmbus, CONFIG_SYS_MAXARGS, 1, do_pmbus,
+ "PMBus 1.x device interrogation and control",
+ "list - list UCLASS_REGULATOR devices (DM bound)\n"
+ "pmbus dev [<bus>:<addr>|<name>] - show / select active PMBus device\n"
+ "pmbus info - identification banner + driver_info\n"
+ "pmbus telemetry - decoded VIN, VOUT, IIN, IOUT, TEMP\n"
+ "pmbus status - decode every STATUS_* register\n"
+ "pmbus dump - hex dump of every standard register\n"
+ "pmbus read <reg> [b|w|s] - raw read (b=byte, w=word, s=string)\n"
+ "pmbus write <reg> <val> [b|w] - raw write\n"
+ "pmbus clear [faults] - issue CLEAR_FAULTS (03h)\n"
+ "pmbus vout [<uV>] - read / set VOUT_COMMAND (microvolts)\n"
+ "pmbus scan [<bus>] - PMBus aware probe of one or all I2C buses\n"
+ "pmbus help - list registered vendor extensions\n"
+ "\n"
+ "Vendor extensions (pmbus <vendor> ...) are registered by per chip\n"
+ "drivers at probe time. Run 'pmbus help' after a chip is probed to\n"
+ "see the available subcommands.\n"
+);
diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index 3c044e67927..2ce67b7bfe2 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -50,6 +50,7 @@ Implementation
logging
makefiles
menus
+ pmbus
printf
smbios
spl
diff --git a/doc/develop/pmbus.rst b/doc/develop/pmbus.rst
new file mode 100644
index 00000000000..12e84c60078
--- /dev/null
+++ b/doc/develop/pmbus.rst
@@ -0,0 +1,633 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+PMBus support in U-Boot
+=======================
+
+This document describes U-Boot's PMBus 1.x support: what it is for,
+how it is structured, and how to add support for a new PMBus chipn
+either from scratch from a chip datasheet or by porting an existing
+Linux ``drivers/hwmon/pmbus/`` driver.
+
+.. contents::
+ :local:
+ :depth: 2
+
+Intent and scope
+----------------
+
+U-Boot's PMBus layer is not a hardware monitoring (hwmon) clone of
+the Linux kernel's ``drivers/hwmon/pmbus/`` subsystem. Linux owns the
+runtime side: continuous polling, sysfs publication, alert IRQ
+handling, fan control loops. U-Boot owns the boot time side. Concretely
+the U-Boot PMBus support exists to:
+
+* Identify the PMBus regulator(s) a board carries at boot:
+ ``MFR_ID``, ``MFR_MODEL``, ``MFR_REVISION`` reads, plus a quick
+ ``STATUS_WORD`` sanity check.
+* Print telemetry so an operator can confirm rail voltages, input
+ current, and temperature before handing off to the kernel. One shot
+ reads, on demand, via the ``pmbus`` and ``regulator`` U-Boot
+ commands (``pmbus dev <name>; pmbus telemetry``,
+ ``regulator dev <name>; regulator value``).
+* Decode chip alerts when a rail trips an over/under voltage,
+ over current, or thermal threshold; so a boot log shows why the
+ previous boot failed, before the kernel even comes up.
+* Optionally trim a critical rail (typically the SoC core) before
+ the kernel takes over; "set the voltage prior to a kernel boot
+ to better protect the board". This is the existing
+ ``board/nxp/common/vid.c`` AVS path and any future per board
+ speed binning trim.
+
+Out of scope, by design:
+
+* No periodic polling. No worker thread. No background updates.
+* No sysfs / procfs / userspace surface. U-Boot has none.
+* No fan speed control loop. The kernel runs that.
+* No long tail of virtual sensor registers (``PMBUS_VIRT_*``).
+* No sensor caching / update timestamps.
+
+If you find yourself wanting any of those, the answer is "wait until
+Linux comes up". Keep U-Boot's PMBus surface minimal.
+
+Architecture overview
+---------------------
+
+The framework is split into four layers (layer 3 comes in two
+flavours, 3a and 3b),
+
+::
+
+ +----------------------------------------+
+ | Layer 1: include/pmbus.h |
+ | Standard PMBus 1.x command codes, |
+ | numeric format enum, sensor class |
+ | enum, struct pmbus_driver_info, |
+ | decoder + transport prototypes, |
+ | STATUS_WORD bit names. |
+ +----------------------------------------+
+ | Layer 2: lib/pmbus.c |
+ | Format decoders (LINEAR11/LINEAR16/|
+ | DIRECT) and encoder (LINEAR16), |
+ | two stage SMBus block read helper, |
+ | STATUS_*-bit print tables, generic |
+ | dispatcher pmbus_reg2data(). |
+ +----------------------------------------+
+ | Layer 3a: drivers/power/regulator/ |
+ | <chip>.c |
+ | UCLASS_REGULATOR per chip drivers |
+ | ; one struct pmbus_driver_info |
+ | plus regulator set_value/get_value |
+ | ops. Optional: per chip identify() |
+ | hook to refine format from the |
+ | chip's own VOUT_MODE. |
+ +----------------------------------------+
+ | Layer 3b: drivers/power/regulator/ |
+ | pmbus_generic.c |
+ | Catch all driver matching |
+ | compatible = "pmbus". |
+ | Auto detects format via VOUT_MODE |
+ | and PMBUS_QUERY where supported. |
+ | Use for compliant chips with no |
+ | per chip driver yet; ship |
+ | telemetry today, write a per chip |
+ | driver later only if quirks demand |
+ | it. |
+ +----------------------------------------+
+ | Layer 4: board/<vendor>/<board>/ |
+ | <chip>_diag.c |
+ | Diagnostic commands only: |
+ | <chip>_info / <chip>_raw |
+ | Reads via regulator_get_value() |
+ | and lib/pmbus.c helpers. LINEAR / |
+ | DIRECT math NOT here. |
+ +----------------------------------------+
+
+Generic vs. board specific separation rule. Layer 1, 2, and 3
+files are tree level and platform agnostic. Their comments may
+reference only:
+
+* the PMBus 1.x specification, and
+* chip manufacturer datasheets.
+
+Never a specific board, SoC, or product. Board-specific quirks
+(a particular bus number, a particular slave address, a particular
+PCB feedback divider, board local design notes) live exclusively in
+``board/<vendor>/<board>/`` files.
+
+CLI commands
+------------
+
+The framework publishes one top level command, ``pmbus``, plus a
+vendor namespace dispatcher so per chip code can register chip
+specific extensions without touching the framework.
+
+Active device model
+~~~~~~~~~~~~~~~~~~~
+
+``pmbus`` mirrors the ``regulator`` command: select an active device
+once, then operate on it across subcommands. The active device is
+selected by I2C bus and 7 bit address::
+
+ => pmbus dev 0:0x10
+ pmbus: active i2c0:0x10 MFR_ID="MPS" MFR_MODEL="MPQ8785" vendor=mps
+
+The framework probes ``MFR_ID`` (in both natural and reverse byte
+orders) at selection time, looks the result up in the chip match
+registry populated by per chip code via ``pmbus_register_chip()``,
+and caches the matched ``pmbus_driver_info``. All subsequent
+subcommands consume that cached metadata.
+
+Standard subcommands
+~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ pmbus list list UCLASS_REGULATOR devices (DM bound)
+ pmbus dev [<bus>:<addr>] show / select active PMBus device
+ pmbus info identification banner + driver_info
+ pmbus telemetry decoded VIN, VOUT, IIN, IOUT, TEMP
+ pmbus status decode every STATUS_* register
+ pmbus dump hex dump of every standard register
+ pmbus read <reg> [b|w|s] raw read (b=byte, w=word, s=string)
+ pmbus write <reg> <val> [b|w] raw write
+ pmbus clear [faults] issue CLEAR_FAULTS (03h)
+ pmbus vout [<uV>] read or set VOUT_COMMAND (microvolts)
+ pmbus scan [<bus>] PMBus aware probe of one or all I2C buses
+
+The ``<reg>`` argument accepts either a hexadecimal address
+(``0x88``) or a symbolic name (``READ_VIN``, ``VOUT_MODE``,
+``MFR_ID``). Format selectors after the register select the SMBus
+transaction width: ``b`` for byte, ``w`` for 16 bit little endian
+word, ``s`` for the SMBus block read used by string registers.
+
+Decoded telemetry honours the active device's ``pmbus_driver_info``;
+when no chip match has been registered, VOUT falls back to LINEAR16
+driven by ``VOUT_MODE`` and the other sensors fall back to LINEAR11.
+
+Vendor namespace
+~~~~~~~~~~~~~~~~
+
+Per chip drivers and board files publish chip specific subcommands
+in the ``pmbus <vendor> ...`` namespace by calling
+``pmbus_register_vendor_handler()`` at init time. The framework
+dispatches ``pmbus mps last``, ``pmbus mps clear last``, and
+``pmbus mps clear force`` to the MPS handler when the active
+device matches the ``mps`` vendor. Additional vendor handlers for
+``lltc``, ``renesas``, etc. land alongside the per chip drivers
+that need them.
+
+Relationship to ``vdd_override`` / ``vdd_read``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The NXP Layerscape ``vdd_override <mV>`` and ``vdd_read`` commands
+remain available in their original form for compatibility with
+existing AVS production scripts. The new ``pmbus vout`` and
+``pmbus vout <uV>`` subcommands cover the read and single shot
+write paths against the same chips, but do not implement
+``vdd_override``'s full sequence (board drop compensation, fuse
+target derivation, multi step convergence loop, atomic
+``PAGE_PLUS_WRITE`` block transaction, ``WRITE_PROTECT`` dance).
+For interactive bring up ``pmbus vout`` is sufficient; for
+production AVS, ``vdd_override`` stays canonical.
+
+Lifecycle: from board boot to Linux handoff
+-------------------------------------------
+
+The PMBus framework spans the entire U-Boot lifecycle. This section
+walks the boot timeline phase by phase, showing when each piece
+comes online and how the regulator uclass and the ``pmbus`` CLI
+converge on the same chip.
+
+Timeline overview
+~~~~~~~~~~~~~~~~~
+
+::
+
+ Phase 0 chip power on chip ramps to NVM default VOUT
+ Phase 1 boot ROM / SPL / TF-A PMBus typically untouched
+ Phase 2 U-Boot relocation, DM init regulators bound, not probed
+ Phase 3 first regulator probe chip driver runs, framework lights up
+ Phase 4 board hooks / boot scripts snapshot, AVS trim, gating
+ Phase 5 Linux handoff DT passed, chip state preserved
+ Phase 6 Linux runtime kernel pmbus driver takes over
+
+Phase 0: chip power on
+~~~~~~~~~~~~~~~~~~~~~~
+
+When the regulator chip receives its input voltage, it ramps its
+output to the VOUT default programmed into its NVM at factory
+provisioning. PMBus is silent: no software runs anywhere on the
+SoC yet.
+
+Phase 1: pre U-Boot stages
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boot ROMs, secondary boot loaders (SPL, ARM TF-A BL2 / BL31)
+typically do not touch PMBus. They focus on PLLs, DDR PHY init,
+and bringing up enough hardware to load the next stage. Some
+platforms have a pre U-Boot AVS path in board specific TF-A
+code that writes ``VOUT_COMMAND`` from a fuse derived target;
+that path is independent of the U-Boot framework described here.
+
+Phase 2: U-Boot relocation and DM init
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+After relocation, U-Boot binds device tree nodes to drivers but
+does not probe them. UCLASS_REGULATOR devices for PMBus chips
+are bound (driver and DT match resolved) but the ``.probe``
+callback has not run yet.
+
+Framework state at this point:
+
+* chip match registry: empty
+* vendor handler registry: empty
+* active device: none
+* regulator uclass: devices bound, none probed
+
+Phase 3: lazy regulator probe
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The first caller into the regulator uclass for a given chip
+triggers the chip driver's ``.probe``. Typical first callers:
+
+* a board ``EVENT_SPY`` at ``EVT_LAST_STAGE_INIT`` (boot snapshot)
+* a U-Boot script: ``regulator dev <name>; regulator value``
+* the ``pmbus dev <name>`` CLI command (resolves to the regulator)
+* another DT consumer with a ``regulator-supplies`` reference
+
+The probe chain looks like this::
+
+ <chip>_probe(dev)
+ pmbus_regulator_probe_common(dev, &<chip>_info, page)
+ dev_read_addr(dev) -> reg = <addr>
+ i2c_get_chip(dev->parent, addr) -> I2C chip handle
+ priv->i2c_dev = handle
+ priv->info = &<chip>_info
+ priv->page = page
+ (page > 0) write PMBUS_PAGE
+ <chip>_identify_vout(priv->i2c_dev) [optional]
+ read VOUT_MODE; refine info->format[PSC_VOLTAGE_OUT]
+ pmbus_regulator_apply_voltage_scale(dev, fb_div) [optional]
+ write PMBUS_VOUT_SCALE_LOOP if DT property set
+ pmbus_register_chip(&<chip>_match) [idempotent]
+ pmbus_register_vendor_handler(&<chip>_op) [idempotent]
+
+Once probed, three independent surfaces are functional against
+the same chip:
+
+* the regulator uclass API (``regulator_get_value``,
+ ``regulator_set_value``, ``regulator_get_enable``,
+ ``regulator_set_enable``)
+* the ``pmbus`` CLI (chip is reachable by name through
+ ``pmbus_resolve_by_name()``, by raw ``<bus>:<addr>`` through
+ ``pmbus_set_active()``)
+* the chip's vendor extension subcommands (``pmbus <vendor> ...``)
+
+Phase 4: board hooks and boot scripts
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boards hook the boot flow at well known points to drive board
+specific PMBus behaviour. The framework prescribes none of these;
+they are conventions:
+
+* boot time rail snapshot. An ``EVENT_SPY`` at
+ ``EVT_LAST_STAGE_INIT`` reads telemetry through the regulator
+ uclass and prints a one shot summary to the console. Useful
+ for operator visibility on serial during bring up.
+
+* pre kernel rail trim (AVS). A board hook in
+ ``board_late_init`` or a custom event spy reads a fuse derived
+ target voltage and calls ``regulator_set_value_force()`` to
+ trim the SoC core rail before kernel handoff.
+
+* Linux handoff gate. A bootcmd reads the rail voltage
+ through the regulator command and refuses to boot Linux if
+ the rail is outside the expected range.
+
+Phase 5: Linux handoff
+~~~~~~~~~~~~~~~~~~~~~~
+
+When U-Boot transfers control to Linux, it passes the device
+tree (potentially patched). The DT compatible strings for PMBus
+regulators must match those in the upstream kernel binding so
+the kernel's ``drivers/hwmon/pmbus/<chip>.c`` picks them up.
+Property names are shared with the kernel binding
+(``regulator-name``, ``regulator-min-microvolt``,
+``mps,vout-fb-divider-ratio-permille``, etc.); see "DT alignment
+with Linux" below.
+
+The chip itself is left in the state U-Boot wrote it to. If
+U-Boot trimmed VOUT, the chip stays at the trimmed voltage
+through handoff. ``CLEAR_FAULTS`` state is preserved unless an
+operator explicitly issued one.
+
+Phase 6: Linux runtime
+~~~~~~~~~~~~~~~~~~~~~~
+
+Linux's ``drivers/hwmon/pmbus/pmbus_core.c`` probes the chip,
+exposes telemetry under ``/sys/class/hwmon``, and takes over
+runtime voltage management through its regulator subsystem.
+The hwmon framework polls periodically; U-Boot does not.
+
+Operation paths through the regulator uclass
+--------------------------------------------
+
+After the first probe completes, calls into the regulator uclass
+for a PMBus chip flow through the shared helper.
+
+Read VOUT::
+
+ regulator_get_value(dev)
+ -> dm_regulator_ops->get_value
+ -> pmbus_regulator_get_value(dev)
+ pmbus_regulator_select_page(priv)
+ pmbus_read_byte(priv->i2c_dev, VOUT_MODE, &mode)
+ pmbus_read_word(priv->i2c_dev, READ_VOUT, &raw)
+ pmbus_reg2data(priv->info, PSC_VOLTAGE_OUT, raw, mode)
+ -> reg2data_linear16 (mode = 0)
+ -> reg2data_direct (chip configured for DIRECT)
+ return engineering value (microvolts)
+
+Write VOUT::
+
+ regulator_set_value(dev, uV)
+ -> dm_regulator_ops->set_value
+ -> pmbus_regulator_set_value(dev, uV)
+ pmbus_regulator_select_page(priv)
+ pmbus_read_byte(VOUT_MODE)
+ check (mode == LINEAR) [LINEAR16 only today]
+ raw = pmbus_data2reg_linear16(uV, mode)
+ dm_i2c_write(VOUT_COMMAND, raw)
+
+Read / write enable bit::
+
+ regulator_get_enable(dev)
+ -> pmbus_regulator_get_enable(dev)
+ pmbus_read_byte(OPERATION) & PB_OPERATION_ON
+
+ regulator_set_enable(dev, on)
+ -> pmbus_regulator_set_enable(dev, on)
+ read OPERATION, set or clear PB_OPERATION_ON, write back
+
+Bus traffic per call:
+
+* ``get_value`` : 1 byte read (VOUT_MODE) + 1 word read (READ_VOUT)
+ + 1 byte write (PAGE) when ``page > 0``
+* ``set_value`` : 1 byte read (VOUT_MODE) + 1 word write (VOUT_COMMAND)
+ + 1 byte write (PAGE) when ``page > 0``
+* ``get_enable`` : 1 byte read (OPERATION)
+* ``set_enable`` : 1 byte read (OPERATION) + 1 byte write (OPERATION)
+
+Common board hook patterns
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Boot time rail snapshot::
+
+ static int my_board_pmbus_snapshot(void)
+ {
+ struct udevice *reg;
+
+ if (regulator_get_by_platname("MY_RAIL", ®))
+ return 0;
+ printf("MY_RAIL: VOUT = %d uV, enabled = %d\n",
+ regulator_get_value(reg),
+ regulator_get_enable(reg));
+ return 0;
+ }
+ EVENT_SPY_SIMPLE(EVT_LAST_STAGE_INIT, my_board_pmbus_snapshot);
+
+The first call to ``regulator_get_value()`` triggers the chip
+driver's ``.probe``, which seeds the chip match and vendor
+extension registries. Subsequent ``pmbus`` CLI commands work
+without further setup.
+
+Pre kernel rail trim (AVS)::
+
+ int board_late_init(void)
+ {
+ struct udevice *reg;
+ int target_uV = compute_avs_target();
+
+ if (regulator_get_by_platname("VDD_CORE", ®))
+ return 0;
+ return regulator_set_value_force(reg, target_uV);
+ }
+
+Use ``regulator_set_value_force()`` when the target may sit
+outside the DT declared ``regulator-min-microvolt`` /
+``regulator-max-microvolt`` range; force bypasses the bounds
+check.
+
+Adding a new PMBus chip from scratch
+------------------------------------
+
+Use this path when the chip has no Linux driver yet, or when you want
+to validate the U-Boot port against the datasheet alone.
+
+1. Confirm PMBus 1.x compliance level. Locate in the chip
+ datasheet:
+
+ which PMBus standard command codes the chip implements
+ (``READ_VIN``, ``READ_VOUT``, ``STATUS_WORD``, ``MFR_ID`` ...),
+ which numeric format(s) it uses for VOUT (LINEAR16 with the
+ exponent in ``VOUT_MODE``, DIRECT with chip specific m/b/R, or
+ VID with one of the documented VRM tables),
+ which numeric format it uses for VIN, IIN, IOUT, TEMPERATURE
+ (most commonly LINEAR11; some MPS / MPS derivative chips use
+ DIRECT instead),
+ how many output rails it exposes (single page parts vs.
+ multi rail PMBus pages).
+
+2. Declare a ``struct pmbus_driver_info``. Wire each sensor
+ class to one ``enum pmbus_data_format``, plus the m/b/R triple if
+ the format is DIRECT::
+
+ static struct pmbus_driver_info chipname_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_direct,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear,
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_direct,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_IN] = 4, .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_CURRENT_OUT] = 16, .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_TEMPERATURE] = 1, .R[PSC_TEMPERATURE] = 0,
+ };
+
+3. Bind to a DT compatible. Use the lowercase ``vendor,chip``
+ tuple Linux uses (see "DT alignment with Linux" below). Add the
+ driver under ``drivers/power/regulator/`` matching the existing
+ skeleton (``fan53555.c``, ``pca9450.c``).
+
+4. Rely on the DT binding from the Linux kernel which is imported into
+ U-Boot under ``dts/upstream/Bindings/`` (for PMBus chips,
+ ``dts/upstream/Bindings/hwmon/pmbus/``).
+
+5. Smoke test. With the chip wired up in DT::
+
+ => regulator dev <name>
+ => regulator value
+ => regulator info
+
+ Numbers should match the bench measurement to within the chip's
+ advertised LSB.
+
+Porting an existing Linux PMBus driver to U-Boot
+------------------------------------------------
+
+When the chip already has a ``linux/drivers/hwmon/pmbus/<chip>.c``,
+that driver is the authoritative reference for format, coefficients,
+and quirks. Take what carries; leave what does not.
+
+What carries verbatim
+~~~~~~~~~~~~~~~~~~~~~
+
+* Numeric formats (``format[PSC_*]``).
+* DIRECT coefficients (``m[]``, ``b[]``, ``R[]``).
+* Per page count and per page functionality bits (``pages``,
+ ``func[]``).
+* VOUT_MODE driven per chip identify hook (e.g. MPQ8785's
+ switch between LINEAR16 and VID coerced DIRECT m=64 R=1).
+* Vendor register addresses for chip specific quirks (fault
+ history, scale-loop, page mapping).
+
+What does not carry
+~~~~~~~~~~~~~~~~~~~~~~~
+
+* ``hwmon_device_register()`` and the attribute groups it consumes.
+* ``struct pmbus_data`` / ``update_lock`` / ``last_updated``
+ U-Boot has no caching layer.
+* ALERT# IRQ wiring; U-Boot is single threaded boot code.
+* Fan control hooks (``read_fan_*``, ``set_pwm_*``).
+* Virtual register handling (``PMBUS_VIRT_READ_VIN_*`` etc.); those
+ are entirely a hwmon publication aid.
+* ``module_i2c_driver(...)`` and ``MODULE_*`` macros; U-Boot uses
+ ``U_BOOT_DRIVER(...)``.
+
+Worked example: porting MPQ8785
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Linux's ``drivers/hwmon/pmbus/mpq8785.c`` is 193 LOC; the U-Boot
+equivalent is ~150 LOC.
+
+The ``mpq8785_info`` struct transcribes verbatim::
+
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = direct, .m[PSC_VOLTAGE_IN] = 4, .R[PSC_VOLTAGE_IN] = 1,
+ .format[PSC_CURRENT_OUT] = direct, .m[PSC_CURRENT_OUT] = 16, .R[PSC_CURRENT_OUT] = 0,
+ .format[PSC_TEMPERATURE] = direct, .m[PSC_TEMPERATURE] = 1, .R[PSC_TEMPERATURE] = 0,
+
+The VOUT format is decided at probe time from VOUT_MODE bits[7:5] :
+mode 0 means LINEAR16, mode 1 or 2 means DIRECT m=64 R=1 (the chip's
+"VID" mode is coerced to DIRECT by the driver). Translate Linux's
+``mpq8785_identify()`` 1:1.
+
+The per chip quirks that carry over:
+
+* MPS NVM string byte order: chip stores ``S P M`` for the human
+ string ``MPS``. ``pmbus_read_string()`` accepts a ``reverse_bytes``
+ flag for this case.
+* ``mps,vout-fb-divider-ratio-permille`` DT property maps to
+ ``VOUT_SCALE_LOOP`` write at probe time.
+
+The quirks that do not carry over:
+
+* The ``PMBUS_VIRT_*`` virtual sensor wiring. Drop entirely.
+* The ``hwmon_chip_info`` attribute group registration.
+* The ``MODULE_AUTHOR`` / ``MODULE_LICENSE`` declarations.
+
+Using the generic ``compatible = "pmbus"`` driver
+-------------------------------------------------
+
+When a board carries a PMBus chip without a per chip U-Boot driver,
+the catch all ``drivers/power/regulator/pmbus_generic.c`` (Layer 3b)
+binds against ``compatible = "pmbus"``. It auto detects format via
+``VOUT_MODE`` and ``PMBUS_QUERY`` (where the chip supports it) and
+provides telemetry + voltage set/get against the standard PMBus 1.x
+subset.
+
+Decision tree:
+
+1. Try the generic driver first. Add the regulator node to the
+ board DT with ``compatible = "pmbus"`` plus the standard
+ regulator properties. Boot, run ``regulator value``, compare
+ against bench measurement.
+2. Switch to a per chip driver only when the generic one is
+ wrong: telemetry shows wrong values (chip uses DIRECT with
+ non default coefficients), an alert can't be decoded (chip has
+ vendor specific status bits), AVS is needed (the boot path has
+ to actively trim VOUT before kernel handoff), or the chip has an
+ ADDR-pin auto promotion / VID coercion / vendor register quirk.
+
+DT alignment with Linux
+-----------------------
+
+The same ``.dts`` file should work under both U-Boot (BL33) and Linux
+post handoff. To make that possible:
+
+* Reuse the upstream Linux compatible for every PMBus chip. Look
+ in ``linux/Documentation/devicetree/bindings/hwmon/pmbus/`` and
+ ``linux/Documentation/devicetree/bindings/regulator/``. The
+ ``<vendor>,<chip>`` tuple from the kernel binding goes into U-Boot's
+ ``of_match_table`` unchanged.
+* Reuse Linux property names verbatim: ``regulator-name``,
+ ``regulator-min-microvolt``, ``regulator-max-microvolt``,
+ ``regulator-boot-on``, ``regulator-always-on``,
+ ``mps,vout-fb-divider-ratio-permille``, etc.
+* The DT binding is the kernel's, imported under
+ ``dts/upstream/Bindings/`` (PMBus chips live in
+ ``dts/upstream/Bindings/hwmon/pmbus/``).
+
+Multi rail/multi page chips (e.g. ISL68137 with seven outputs)
+declare each rail as a child regulator node with ``reg = <page>``;
+each child binds as a UCLASS_REGULATOR with that PMBus PAGE setting
+applied at every read/write.
+
+Common pitfalls
+---------------
+
+These have all bitten contributors during nbxv3 bring up; record them
+here so the next port doesn't repeat them.
+
+* VOUT_MODE/DIRECT format confusion. Most generic PMBus call
+ sites assume LINEAR16. Several MPS chips report VOUT in DIRECT
+ format with chip specific m/b/R after a single VOUT_MODE read,
+ the same chip read at the same address produces different
+ numbers depending on the format the driver applies. Always read
+ ``VOUT_MODE`` at probe time and switch the decoder accordingly.
+ Linux's per chip ``identify()`` callbacks document the exact
+ rules; copy them rather than guessing.
+* SMBus block read protocol. Some I2C controllers strict check
+ block read transactions: the master must read the length byte
+ first, then reissue the read for the payload. Over reading a
+ fixed length and ignoring the length byte works on lenient
+ controllers but errors on strict ones. ``pmbus_read_string()``
+ does the two stage read; use it.
+* I2C bus number stability. ``uclass_get_device_by_seq()``
+ uses the DT alias index (``i2c0`` -> ``UCLASS_I2C`` seq 0) when
+ aliases are declared, otherwise falls back to probe order which
+ varies with which controllers are enabled in the defconfig.
+ Always declare DT aliases for I2C buses you reference by index.
+* ADDR-pin auto addressessing. Some chips (notably MPS parts) decode
+ their PMBus 7-bit address from an external resistor divider on
+ ADDR_VBOOT. The "default" address in the datasheet is the
+ factory fused slot; a board with a different divider or a die
+ with a different revision can land in another window. If the
+ driver hardcodes the default and the board side scan finds the
+ chip in another window, auto promote the working address rather
+ than failing the probe.
+* MFR string byte order. Most PMBus chips return ``MFR_ID``
+ characters in human order. Some MPS personalities reverse them.
+ Pass ``reverse_bytes=true`` to ``pmbus_read_string()`` for those;
+ spec compliant chips pass false.
+
+References
+----------
+
+* Linux PMBus core: ``linux/drivers/hwmon/pmbus/pmbus_core.c``,
+ decoder reference; ignore the hwmon publication and caching layers.
+* Linux PMBus header: ``linux/drivers/hwmon/pmbus/pmbus.h``; API
+ surface reference; many constants and the ``struct
+ pmbus_driver_info`` shape are mirrored verbatim into U-Boot's
+ ``include/pmbus.h``.
+* Linux DT bindings:
+ ``linux/Documentation/devicetree/bindings/hwmon/pmbus/``.
diff --git a/include/pmbus.h b/include/pmbus.h
new file mode 100644
index 00000000000..969108e5b53
--- /dev/null
+++ b/include/pmbus.h
@@ -0,0 +1,629 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * PMBus 1.x command codes, numeric format decoders, and driver_info
+ * scaffolding for U-Boot.
+ *
+ * Intents
+ *
+ * U-Boot's PMBus support is not a hwmon clone. It shall be used to:
+ * 1. identify PMBus regulators a board carries at boot,
+ * 2. print telemetry so an operator can confirm rail voltages and
+ * fault status before handing off to the kernel,
+ * 3. decode chip alerts when a rail trips an over/under voltage,
+ * over current, or thermal threshold,
+ * 4. optionally trim a critical rail before kernel boot, to better
+ * protect the board.
+ *
+ * No periodic polling, no /sys, no userspace surface, no fan control
+ * loops. Linux owns those. See doc/develop/pmbus.rst for the full
+ * porting guide and policy notes.
+ *
+ * Linux relationship
+ *
+ * Constants (command codes, status bit names, sensor class enum,
+ * format enum) are mirrored verbatim from
+ * linux/drivers/hwmon/pmbus/pmbus.h
+ * with attribution; this is standardised data and copying it avoids
+ * accidental drift. Decoders (LINEAR11/16, DIRECT, VID, IEEE754) are
+ * reimplemented from the PMBus 1.x spec rather than copied. The
+ * surrounding kernel context (struct pmbus_data, hwmon caching,
+ * sysfs publication) does not apply to U-Boot.
+ *
+ * Tree level files (this header, lib/pmbus.c, future per chip drivers
+ * under drivers/power/regulator/) must stay platform agnostic. They
+ * may reference only the PMBus 1.x specification and chip datasheets,
+ * never a specific board, SoC, or product. Board specific quirks
+ * live under board/<vendor>/<board>/.
+ */
+
+#ifndef _PMBUS_H_
+#define _PMBUS_H_
+
+#include <linux/types.h>
+
+struct udevice;
+struct pmbus_driver_info;
+struct pmbus_status_override;
+
+/*
+ * PMBus 1.3 standard command codes (Part II).
+ *
+ * Subset relevant to U-Boot's needs:
+ * - configuration (PAGE, OPERATION, VOUT_*),
+ * - telemetry (READ_VIN, READ_IOUT, READ_TEMPERATURE_1, ...),
+ * - status (STATUS_WORD, STATUS_VOUT, ...),
+ * - identification (MFR_ID, MFR_MODEL, MFR_REVISION).
+ * Chip specific extensions (for example MPS PROTECTION_LAST 0xFB) shall be in
+ * the per chip driver file.
+ */
+#define PMBUS_PAGE 0x00
+#define PMBUS_OPERATION 0x01
+#define PMBUS_ON_OFF_CONFIG 0x02
+#define PMBUS_CLEAR_FAULTS 0x03
+#define PMBUS_PHASE 0x04
+
+#define PMBUS_WRITE_PROTECT 0x10
+
+#define PMBUS_CAPABILITY 0x19
+#define PMBUS_QUERY 0x1a
+#define PMBUS_SMBALERT_MASK 0x1b
+#define PMBUS_VOUT_MODE 0x20
+#define PMBUS_VOUT_COMMAND 0x21
+#define PMBUS_VOUT_TRIM 0x22
+#define PMBUS_VOUT_CAL_OFFSET 0x23
+#define PMBUS_VOUT_MAX 0x24
+#define PMBUS_VOUT_MARGIN_HIGH 0x25
+#define PMBUS_VOUT_MARGIN_LOW 0x26
+#define PMBUS_VOUT_TRANSITION_RATE 0x27
+#define PMBUS_VOUT_DROOP 0x28
+#define PMBUS_VOUT_SCALE_LOOP 0x29
+#define PMBUS_VOUT_SCALE_MONITOR 0x2a
+
+#define PMBUS_COEFFICIENTS 0x30
+#define PMBUS_POUT_MAX 0x31
+
+#define PMBUS_STATUS_BYTE 0x78
+#define PMBUS_STATUS_WORD 0x79
+#define PMBUS_STATUS_VOUT 0x7a
+#define PMBUS_STATUS_IOUT 0x7b
+#define PMBUS_STATUS_INPUT 0x7c
+#define PMBUS_STATUS_TEMPERATURE 0x7d
+#define PMBUS_STATUS_CML 0x7e
+#define PMBUS_STATUS_OTHER 0x7f
+#define PMBUS_STATUS_MFR_SPECIFIC 0x80
+
+#define PMBUS_READ_VIN 0x88
+#define PMBUS_READ_IIN 0x89
+#define PMBUS_READ_VCAP 0x8a
+#define PMBUS_READ_VOUT 0x8b
+#define PMBUS_READ_IOUT 0x8c
+#define PMBUS_READ_TEMPERATURE_1 0x8d
+#define PMBUS_READ_TEMPERATURE_2 0x8e
+#define PMBUS_READ_TEMPERATURE_3 0x8f
+#define PMBUS_READ_DUTY_CYCLE 0x94
+#define PMBUS_READ_FREQUENCY 0x95
+#define PMBUS_READ_POUT 0x96
+#define PMBUS_READ_PIN 0x97
+
+#define PMBUS_REVISION 0x98
+#define PMBUS_MFR_ID 0x99
+#define PMBUS_MFR_MODEL 0x9a
+#define PMBUS_MFR_REVISION 0x9b
+#define PMBUS_MFR_LOCATION 0x9c
+#define PMBUS_MFR_DATE 0x9d
+#define PMBUS_MFR_SERIAL 0x9e
+
+#define PMBUS_IC_DEVICE_ID 0xad
+#define PMBUS_IC_DEVICE_REV 0xae
+
+/* VOUT_MODE upper bits: numeric format selector (Part II sec 8.3). */
+#define PB_VOUT_MODE_MODE_MASK 0xe0
+#define PB_VOUT_MODE_PARAM_MASK 0x1f
+#define PB_VOUT_MODE_LINEAR 0x00
+#define PB_VOUT_MODE_VID 0x20
+#define PB_VOUT_MODE_DIRECT 0x40
+#define PB_VOUT_MODE_IEEE754 0x60
+
+/* STATUS_WORD lower byte (= STATUS_BYTE), Part II sec 10.1.1. */
+#define PB_STATUS_NONE_ABOVE BIT(0)
+#define PB_STATUS_CML BIT(1)
+#define PB_STATUS_TEMPERATURE BIT(2)
+#define PB_STATUS_VIN_UV BIT(3)
+#define PB_STATUS_IOUT_OC BIT(4)
+#define PB_STATUS_VOUT_OV BIT(5)
+#define PB_STATUS_OFF BIT(6)
+#define PB_STATUS_BUSY BIT(7)
+
+/* STATUS_WORD upper byte. */
+#define PB_STATUS_UNKNOWN BIT(8)
+#define PB_STATUS_OTHER BIT(9)
+#define PB_STATUS_FANS BIT(10)
+#define PB_STATUS_POWER_GOOD_N BIT(11)
+#define PB_STATUS_WORD_MFR BIT(12)
+#define PB_STATUS_INPUT BIT(13)
+#define PB_STATUS_IOUT_POUT BIT(14)
+#define PB_STATUS_VOUT BIT(15)
+
+/* STATUS_VOUT (PMBus 1.3.1 Part II sec 17.3, Table 17). */
+#define PB_VOLTAGE_VOUT_MAX_MIN_WARN BIT(3)
+#define PB_VOLTAGE_UV_FAULT BIT(4)
+#define PB_VOLTAGE_UV_WARNING BIT(5)
+#define PB_VOLTAGE_OV_WARNING BIT(6)
+#define PB_VOLTAGE_OV_FAULT BIT(7)
+
+/* STATUS_IOUT (Part II sec 10.6). */
+#define PB_POUT_OP_WARNING BIT(0)
+#define PB_POUT_OP_FAULT BIT(1)
+#define PB_POWER_LIMITING BIT(2)
+#define PB_CURRENT_SHARE_FAULT BIT(3)
+#define PB_IOUT_UC_FAULT BIT(4)
+#define PB_IOUT_OC_WARNING BIT(5)
+#define PB_IOUT_OC_LV_FAULT BIT(6)
+#define PB_IOUT_OC_FAULT BIT(7)
+
+/* STATUS_INPUT (Part II sec 10.7). */
+#define PB_PIN_OP_WARNING BIT(0)
+#define PB_IIN_OC_WARNING BIT(1)
+#define PB_IIN_OC_FAULT BIT(2)
+
+/* STATUS_TEMPERATURE (Part II sec 10.8). */
+#define PB_TEMP_UT_FAULT BIT(4)
+#define PB_TEMP_UT_WARNING BIT(5)
+#define PB_TEMP_OT_WARNING BIT(6)
+#define PB_TEMP_OT_FAULT BIT(7)
+
+/* STATUS_CML (Part II sec 10.9). */
+#define PB_CML_FAULT_OTHER_MEM_LOGIC BIT(0)
+#define PB_CML_FAULT_OTHER_COMM BIT(1)
+#define PB_CML_FAULT_PROCESSOR BIT(3)
+#define PB_CML_FAULT_MEMORY BIT(4)
+#define PB_CML_FAULT_PACKET_ERROR BIT(5)
+#define PB_CML_FAULT_INVALID_DATA BIT(6)
+#define PB_CML_FAULT_INVALID_COMMAND BIT(7)
+
+/*
+ * OPERATION (01h) command bits per PMBus 1.3 Part II sec 9.1. Bit[7]
+ * is the master rail enable; the lower bits select margin high/low
+ * and turn off behaviour (subset surfaced for the regulator helper).
+ */
+#define PB_OPERATION_ON BIT(7)
+
+/*
+ * LINEAR11 numeric format (PMBus 1.3 Part II sec 7): 16 bit register
+ * with a signed 11 bit mantissa in bits[10:0] and a signed 5 bit
+ * exponent in bits[15:11]. Engineering value = mantissa * 2^exponent.
+ */
+#define PB_LINEAR11_MANT_MASK 0x07ff
+#define PB_LINEAR11_MANT_BITS 11
+#define PB_LINEAR11_EXP_SHIFT 11
+#define PB_LINEAR11_EXP_MASK 0x1f
+#define PB_LINEAR11_EXP_BITS 5
+
+/*
+ * Cache buffer sizes for the active device singleton + MFR_* block
+ * reads. PMBus block reads return up to 32 bytes per the SMBus spec;
+ * 16 covers every MFR string seen in practice on regulator class
+ * chips and keeps the singleton compact.
+ */
+#define PMBUS_MFR_STRING_MAX 16
+#define PMBUS_VENDOR_NAME_MAX 8
+#define PMBUS_REGULATOR_NAME_MAX 24
+
+/* PMBus revision identifiers reported by PMBUS_REVISION (98h). */
+#define PMBUS_REV_10 0x00 /* PMBus 1.0 */
+#define PMBUS_REV_11 0x11 /* PMBus 1.1 */
+#define PMBUS_REV_12 0x22 /* PMBus 1.2 */
+#define PMBUS_REV_13 0x33 /* PMBus 1.3 */
+
+/*
+ * Numeric formats and sensor classes.
+ *
+ * Mirrors linux/drivers/hwmon/pmbus/pmbus.h enum pmbus_data_format
+ * and enum pmbus_sensor_classes. A chip's pmbus_driver_info wires
+ * each sensor class to one format and (for DIRECT) to its m/b/R
+ * coefficients.
+ */
+enum pmbus_data_format {
+ pmbus_fmt_linear = 0,
+ pmbus_fmt_ieee754,
+ pmbus_fmt_direct,
+ pmbus_fmt_vid,
+};
+
+enum pmbus_sensor_classes {
+ PSC_VOLTAGE_IN = 0,
+ PSC_VOLTAGE_OUT,
+ PSC_CURRENT_IN,
+ PSC_CURRENT_OUT,
+ PSC_POWER,
+ PSC_TEMPERATURE,
+ PSC_NUM_CLASSES
+};
+
+/*
+ * Per chip identification record. Each per chip driver declares one
+ * of these and points the framework at it. Subset of the kernel
+ * struct pmbus_driver_info: U-Boot has no per page caches, no fan
+ * accessors, no virtual registers, no async sysfs publication.
+ *
+ * pages number of PAGE distinct rails the chip exposes
+ * (1 for single rail parts).
+ * format[] numeric format per sensor class.
+ * m/b/R[] DIRECT format coefficients per sensor class. See
+ * pmbus_reg2data_direct() below for the formula.
+ * Unused for non DIRECT classes.
+ * read_byte_data, read_word_data
+ * optional per chip register translators. Return the
+ * standard register value on success, ENODATA to fall
+ * through to the generic transport, any other negative
+ * errno on bus error.
+ * identify optional probe time hook to discover format and
+ * page count from the chip itself (for example, the
+ * MPQ8785 VOUT_MODE switch between LINEAR and DIRECT).
+ */
+struct pmbus_driver_info {
+ int pages;
+ enum pmbus_data_format format[PSC_NUM_CLASSES];
+ int m[PSC_NUM_CLASSES];
+ int b[PSC_NUM_CLASSES];
+ int R[PSC_NUM_CLASSES];
+
+ int (*read_byte_data)(struct udevice *dev, int page, int reg);
+ int (*read_word_data)(struct udevice *dev, int page, int reg);
+ int (*identify)(struct udevice *dev, struct pmbus_driver_info *info);
+
+ /*
+ * Optional sparse table of chip specific STATUS_* bit name
+ * substitutions. Terminated by an entry with .name = NULL
+ * (matching the convention used by struct udevice_id and
+ * other U-Boot driver tables). NULL pointer means the chip
+ * uses only PMBus 1.x standard names. See struct
+ * pmbus_status_override and pmbus_print_status_bits().
+ */
+ const struct pmbus_status_override *status_overrides;
+
+ /*
+ * Bitmask (BIT(enum pmbus_sensor_classes)) of the sensor classes
+ * this chip actually implements. When non-zero, pmbus_print_telemetry
+ * prints exactly these classes -- mirroring the kernel's per chip
+ * sensor set -- and skips the rest. This is how an MPS buck that
+ * ACKs READ_POUT / READ_IIN with an uncalibrated value still hides
+ * POWER / CURRENT_IN (the kernel's mpq8646 driver exposes neither).
+ * Zero means "not declared": the telemetry printer falls back to a
+ * live pmbus_word_command_supported() probe per class, which is what
+ * the generic driver (compatible = "pmbus") relies on.
+ */
+ u8 classes_present;
+};
+
+/*
+ * Decoder helpers (raw register, returns engineering value in micro
+ * units).
+ *
+ * All return signed micro units (uV, uA, udegC), 64 bit to avoid
+ * overflow on large mantissa times exponent products. The caller
+ * divides by 1000 for milli units, or by 1_000_000 for the integer
+ * engineering value.
+ */
+
+/*
+ * LINEAR11. Bits[15:11] = signed 5 bit exponent Y, bits[10:0] =
+ * signed 11 bit mantissa N. Engineering value = N * 2^Y.
+ *
+ * Used by most PMBus chips for VIN, IIN, IOUT, TEMP. Some MPS
+ * parts deviate (they report DIRECT format with chip specific m/b/R
+ * coefficients); check the chip datasheet against PMBUS_VOUT_MODE
+ * and the Linux per chip driver if porting.
+ */
+s64 pmbus_reg2data_linear11(u16 raw);
+
+/*
+ * LINEAR16. 16 bit unsigned mantissa multiplied by 2^Y, where Y is
+ * the signed 5 bit exponent supplied via VOUT_MODE bits[4:0]. The
+ * caller must read VOUT_MODE (cmd 0x20) and pass it in vout_mode.
+ * Only the mode_mask bits[7:5] = 0 selector is the LINEAR16 path.
+ *
+ * Used for READ_VOUT (8Bh) on chips whose VOUT_MODE selects Linear.
+ * Returns 0 if VOUT_MODE indicates a non Linear mode; the caller
+ * is then expected to dispatch to pmbus_reg2data_direct() with the
+ * appropriate per chip m/b/R, or to pmbus_reg2data_vid() / _ieee754()
+ * if the chip uses those formats.
+ */
+s64 pmbus_reg2data_linear16(u16 raw, u8 vout_mode);
+
+/*
+ * DIRECT. PMBus 1.3 Part II sec 8.4. The chip stores a signed 16 bit
+ * value X; the engineering value Y is one over m, multiplied by the
+ * quantity (X scaled by ten to the power minus R, then offset by
+ * minus b), with chip specific (m, b, R) coefficients.
+ *
+ * In symbolic form: Y = (1/m) * (X * 10**(-R) - b). The negative
+ * exponent and trailing subtraction are math operators in the
+ * formula, not punctuation in the prose.
+ *
+ * Returns micro units. Implementation order matches the Linux
+ * reference (multiply before subtract, scale R then divide by m) to
+ * minimise quantisation drift. m == 0 returns 0.
+ */
+s64 pmbus_reg2data_direct(s16 raw, int m, int b, int R);
+
+/*
+ * Encoder: engineering value (micro units) to LINEAR16 raw register
+ * value. Used by pre kernel rail trim code (see board/nxp/common/vid.c)
+ * to write VOUT_COMMAND from a target voltage. The exponent is
+ * recovered from VOUT_MODE.
+ *
+ * Returns 0 if VOUT_MODE indicates a non Linear format; the caller
+ * must then dispatch to pmbus_data2reg_direct() (DIRECT format) or
+ * the VID / IEEE754 encoders (when those land) per the chip's actual
+ * VOUT_MODE selector.
+ */
+u16 pmbus_data2reg_linear16(s64 micro, u8 vout_mode);
+
+/*
+ * Encoder: engineering value (micro units) to DIRECT raw register
+ * value. Inverse of pmbus_reg2data_direct():
+ *
+ * X = (m * Y + b) * 10^R
+ *
+ * with chip specific (m, b, R) coefficients (typically taken from
+ * the chip's pmbus_driver_info[PSC_VOLTAGE_OUT]). m == 0 returns 0.
+ *
+ * The result is saturated to the s16 range mandated by the PMBus
+ * 1.3 Part II sec 8.4 DIRECT encoding; out of range targets return
+ * 0x7fff or 0x8000 rather than wrapping.
+ */
+u16 pmbus_data2reg_direct(s64 micro, int m, int b, int R);
+
+/*
+ * Dispatcher: pick the right reg2data_* helper based on the chip's
+ * pmbus_driver_info[class]. vout_mode is consulted only for
+ * VOLTAGE_OUT in linear format. For DIRECT, m/b/R are taken from
+ * info. For VID and IEEE754 the dispatcher returns 0 (formats
+ * not yet wired up; add when a consumer lands).
+ */
+s64 pmbus_reg2data(const struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes class,
+ u16 raw, u8 vout_mode);
+
+/*
+ * Transport helpers.
+ *
+ * Thin wrappers over the U-Boot DM I2C primitives that handle PMBus
+ * framing details (little endian word layout, two stage block read,
+ * CLEAR_FAULTS pseudo command without payload).
+ */
+
+/* Read a byte register. */
+int pmbus_read_byte(struct udevice *dev, u8 cmd, u8 *val);
+
+/* Read a 16 bit register, little endian on the wire. */
+int pmbus_read_word(struct udevice *dev, u8 cmd, u16 *val);
+
+/* Write a byte register. */
+int pmbus_write_byte(struct udevice *dev, u8 cmd, u8 val);
+
+/* Write a 16 bit register, little endian on the wire. */
+int pmbus_write_word(struct udevice *dev, u8 cmd, u16 val);
+
+/*
+ * Block read of a vendor string register (MFR_ID, MFR_MODEL,
+ * MFR_REVISION). The first wire byte is the payload length; the
+ * helper does the second read for the payload itself, so even strict
+ * I2C controllers (which forbid over read on block transactions)
+ * work. Output is null terminated and printable only (non printable
+ * bytes are substituted with '.').
+ *
+ * reverse_bytes: some MPS NVM personalities store ASCII strings
+ * LSB first (chip returns "SPM" for the human string "MPS"); pass
+ * true to reverse on copy. Spec compliant chips pass false.
+ *
+ * Returns string length on success or a negative errno on bus error
+ * or invalid length byte. outsz must be at least 2.
+ */
+int pmbus_read_string(struct udevice *dev, u8 cmd, char *out, int outsz,
+ bool reverse_bytes);
+
+/* Issue a CLEAR_FAULTS (03h) write. Clears RAM sticky STATUS_*. */
+int pmbus_clear_faults(struct udevice *dev);
+
+/*
+ * Capability probe: is a word sized command implemented by the chip?
+ *
+ * Primary signal is the bus NAK -- compliant parts do not ACK a
+ * command they do not implement, so the word read fails. Secondary
+ * signal is a clean -> dirty transition of STATUS_CML[INVALID_COMMAND]
+ * across the read (a chip that ACKs but does not implement the
+ * register raises it). Non destructive: never issues CLEAR_FAULTS, so
+ * sticky fault history survives for a subsequent pmbus status; a
+ * pre existing CML fault disables the secondary signal so it cannot
+ * produce a false "unsupported".
+ *
+ * Returns true if the command appears supported, false otherwise.
+ */
+bool pmbus_word_command_supported(struct udevice *dev, u8 reg);
+
+/*
+ * High level snapshot printers shared by the pmbus CLI and board
+ * boot time diagnostics. Both operate on the current pmbus_active()
+ * device (select it first via pmbus_set_active()); chip is the I2C
+ * handle from pmbus_active_get_i2c() / the CLI's require_active().
+ *
+ * pmbus_print_telemetry: decodes VIN / VOUT / IIN / IOUT / POUT / TEMP
+ * through the active device's pmbus_driver_info (LINEAR / DIRECT / VID
+ * per VOUT_MODE and per class format), skipping commands the chip does
+ * not implement (pmbus_word_command_supported). Falls back to
+ * LINEAR16 / LINEAR11 when no driver_info is cached. Caller prints the
+ * header line.
+ *
+ * pmbus_print_status_word: reads + decodes STATUS_WORD with the active
+ * device's chip specific status_overrides, if any.
+ */
+void pmbus_print_telemetry(struct udevice *chip);
+void pmbus_print_status_word(struct udevice *chip);
+
+/*
+ * Status bit name decoding.
+ *
+ * Sparse mask to name table. pmbus_print_bits() emits only the bits
+ * that are SET in v, joined by |; if no bit is set, prints
+ * clean. Bits not in the table are silently ignored (RESERVED bits
+ * or chip specific bits handled by a separate per chip table).
+ */
+struct pmbus_bit {
+ u16 mask;
+ const char *name;
+};
+
+void pmbus_print_bits(u16 v, const struct pmbus_bit *tab);
+
+/*
+ * Per chip override entry. When a chip reuses a PMBus standard
+ * STATUS bit for a documented chip specific signal (for example MPS
+ * uses STATUS_WORD bit[12] = MFR_SPECIFIC as NVM_SUMMARY, bit[8] =
+ * UNKNOWN as WATCH_DOG, bit[0] = NONE_ABOVE as DRMOS_FAULT), the
+ * per chip driver supplies a sparse table of (reg, mask, name)
+ * triples and pmbus_print_status_bits() substitutes the chip name
+ * for the standard one when the bit is set.
+ *
+ * reg is one of PMBUS_STATUS_WORD / VOUT / IOUT / INPUT /
+ * TEMPERATURE / CML, so the same table can carry overrides for
+ * every status register on the chip in one place. Tables that omit
+ * a (reg, mask) leave the standard name in place.
+ *
+ * Override entries whose mask is NOT in the standard table are
+ * still printed (the chip can extend coverage beyond PMBus 1.x for
+ * vendor specific bits in standard registers).
+ *
+ * Tables are NULL terminated: the last entry has .name = NULL.
+ * Following the same convention U-Boot uses for struct udevice_id
+ * and other driver tables avoids the explicit-count foot-gun.
+ */
+struct pmbus_status_override {
+ u8 reg;
+ u16 mask;
+ const char *name;
+};
+
+/*
+ * Print the bit names of a STATUS_* register value. For each bit
+ * set in v, prefer a chip override matching (reg, mask) over the
+ * standard std table entry; if neither matches, the bit is
+ * silently skipped (RESERVED). If no bit is set at all, prints
+ * clean. Pass ovr = NULL to disable the override path.
+ */
+void pmbus_print_status_bits(u8 reg, u16 v,
+ const struct pmbus_bit *std,
+ const struct pmbus_status_override *ovr);
+
+/*
+ * Built in PMBus 1.3 standard bit tables (use these from per chip
+ * drivers and board diagnostics; vendor extensions go in chip local
+ * tables that the per chip driver passes alongside these).
+ */
+/*
+ * All tables below are NULL terminated (last entry has .name = NULL),
+ * so callers walk with for (t = tab; t && t->name; t++) and the
+ * helpers above need no count argument.
+ */
+extern const struct pmbus_bit pmbus_status_word_bits[];
+extern const struct pmbus_bit pmbus_status_vout_bits[];
+extern const struct pmbus_bit pmbus_status_iout_bits[];
+extern const struct pmbus_bit pmbus_status_input_bits[];
+extern const struct pmbus_bit pmbus_status_temp_bits[];
+extern const struct pmbus_bit pmbus_status_cml_bits[];
+
+/*
+ * Active device tracking for the pmbus U-Boot CLI.
+ *
+ * The framework keeps one active PMBus device. It is selected by
+ * pmbus dev <bus>:<addr> (raw I2C tuple) and remembered across
+ * subcommands so subsequent invocations of pmbus telemetry,
+ * pmbus status, pmbus dump, etc. operate on the same chip
+ * without re-typing the address.
+ *
+ * pmbus_set_active() probes the chip's MFR_ID at the given address,
+ * looks the result up in the chip-match registry (populated by
+ * per chip drivers via pmbus_register_chip()), and caches the
+ * resulting struct pmbus_driver_info. Subcommands consult
+ * pmbus_active() to find the cached metadata.
+ */
+struct pmbus_active_dev {
+ bool valid;
+ int bus_seq;
+ u8 addr;
+ char vendor[PMBUS_VENDOR_NAME_MAX];
+ char name[PMBUS_REGULATOR_NAME_MAX]; /* DT regulator-name when bound; "" otherwise */
+ char mfr_id[PMBUS_MFR_STRING_MAX];
+ char mfr_model[PMBUS_MFR_STRING_MAX];
+ char mfr_revision[PMBUS_MFR_STRING_MAX];
+ const struct pmbus_driver_info *info;
+};
+
+const struct pmbus_active_dev *pmbus_active(void);
+int pmbus_active_get_i2c(struct udevice **i2c_dev);
+int pmbus_set_active(int bus_seq, u8 addr);
+void pmbus_clear_active(void);
+
+/*
+ * Per chip driver / board file registers a chip match so the
+ * framework can associate an MFR_ID prefix (read at probe time)
+ * with a vendor namespace ("mps", "lltc", "renesas", ...) and a
+ * pmbus_driver_info pointer. The first matching entry wins.
+ *
+ * mfr_id_reverse flags MPS style chips that store the MFR_ID
+ * string LSB first (chip returns "SPM" for the human string
+ * "MPS"); the framework reads the string in both orderings and
+ * matches against the prefix in the natural reading.
+ */
+struct pmbus_chip_match {
+ const char *mfr_id;
+ bool mfr_id_reverse;
+ const char *vendor;
+ const struct pmbus_driver_info *info;
+};
+
+int pmbus_register_chip(const struct pmbus_chip_match *match);
+
+/*
+ * Resolve a regulator-name (DT regulator-name property) to its
+ * (bus, addr) tuple by walking UCLASS_REGULATOR. Used by the
+ * pmbus dev <name> CLI alias so a chip bound through DT can be
+ * selected by its human readable rail name (e.g. "+0V8_VDD")
+ * instead of the i2c bus / address pair. Returns 0 on success
+ * (out parameters populated and the regulator probed), or a
+ * negative errno if no match is found or the bus / address cannot
+ * be derived. Available only when CONFIG_DM_REGULATOR is set.
+ */
+int pmbus_resolve_by_name(const char *name, int *bus_seq, u8 *addr);
+
+/*
+ * Vendor extension dispatcher.
+ *
+ * When the user types pmbus <vendor> <args...>, the framework
+ * looks up the registered handler for <vendor> and calls it with
+ * the argv tail (argv[0] = "<vendor>"). The handler operates on
+ * pmbus_active(), or returns CMD_RET_USAGE if the active device is
+ * not from this vendor.
+ *
+ * Per chip drivers register their vendor handler at init time. The
+ * MPS extension publishes pmbus mps last, pmbus mps clear last,
+ * and pmbus mps clear force.
+ */
+typedef int (*pmbus_vendor_handler_t)(struct cmd_tbl *cmdtp, int flag,
+ int argc, char *const argv[]);
+
+struct pmbus_vendor_op {
+ const char *vendor;
+ pmbus_vendor_handler_t handler;
+ const char *help;
+};
+
+int pmbus_register_vendor_handler(const struct pmbus_vendor_op *op);
+const struct pmbus_vendor_op *pmbus_lookup_vendor(const char *vendor);
+unsigned int pmbus_vendor_count(void);
+const struct pmbus_vendor_op *pmbus_vendor_at(unsigned int i);
+
+#endif /* _PMBUS_H_ */
diff --git a/lib/Kconfig b/lib/Kconfig
index 9e0f0ad7d06..24e55ade4d3 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -283,6 +283,22 @@ config PANIC_HANG
development since you can try to debug the conditions that lead to
the situation.
+config PMBUS
+ bool "PMBus 1.x decoder and transport helpers"
+ depends on DM_I2C
+ help
+ Enable include/pmbus.h and lib/pmbus.c: standard PMBus 1.x
+ command codes, LINEAR11, LINEAR16, and DIRECT numeric format
+ decoders, the two stage SMBus block read helper used for
+ MFR_ID, MFR_MODEL, and MFR_REVISION reads, and the table
+ driven STATUS_* bit print helper.
+
+ This is the substrate for any pre kernel PMBus consumer in
+ U-Boot (board/nxp/common/vid.c rail trim, board local telemetry
+ diagnostics, future per chip regulator drivers under
+ drivers/power/regulator/). It is not a hwmon clone. See
+ doc/develop/pmbus.rst for the policy notes.
+
config REGEX
bool "Enable regular expression support"
default y if NET_LEGACY
diff --git a/lib/Makefile b/lib/Makefile
index d0ffabc2b47..222378a8531 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -53,6 +53,7 @@ obj-y += rc4.o
obj-$(CONFIG_RBTREE) += rbtree.o
obj-$(CONFIG_BITREVERSE) += bitrev.o
obj-y += list_sort.o
+obj-$(CONFIG_PMBUS) += pmbus.o
endif
obj-$(CONFIG_$(PHASE_)TPM) += tpm-common.o
diff --git a/lib/pmbus.c b/lib/pmbus.c
new file mode 100644
index 00000000000..d49576ad3bd
--- /dev/null
+++ b/lib/pmbus.c
@@ -0,0 +1,859 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * PMBus 1.x decoders, transport helpers, and standard status bit
+ * tables for U-Boot. See include/pmbus.h for the API surface and
+ * doc/develop/pmbus.rst for the porting guide.
+ *
+ * Decoder math is implemented from the PMBus 1.3 specification:
+ * 1. Part I (transport): see
+ * doc/PMBus/PMBus_Specification_Rev_1_3_1_Part_I_20150313.{pdf,txt}
+ * 2. Part II (commands): see
+ * doc/PMBus/PMBus_Specification_Rev_1_3_1_Part_II_20150313.{pdf,txt}
+ *
+ * Reference Linux implementation: linux/drivers/hwmon/pmbus/pmbus_core.c
+ * (the kernel side `struct pmbus_data` caching and hwmon publication
+ * layers do not apply; only the arithmetic carries over).
+ *
+ * No code in this file may reference a specific board, SoC, or
+ * product. Per chip quirks (MPS DIRECT format LSBs, vendor registers,
+ * VID coercion, ADDR_VBOOT auto promotion, and the like) belong in
+ * per chip drivers under drivers/power/regulator/ or in board local
+ * files under board/<vendor>/<board>/.
+ */
+
+#include <ctype.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <limits.h>
+#include <linux/bitops.h>
+#include <power/regulator.h>
+
+static int pmbus_sign_extend(unsigned int v, unsigned int width)
+{
+ unsigned int mask = (1U << width) - 1U;
+ unsigned int sign = 1U << (width - 1U);
+
+ v &= mask;
+ if (v & sign)
+ v |= ~mask;
+ return (int)v;
+}
+
+s64 pmbus_reg2data_linear11(u16 raw)
+{
+ int mantissa = pmbus_sign_extend(raw & PB_LINEAR11_MANT_MASK,
+ PB_LINEAR11_MANT_BITS);
+ int exponent = pmbus_sign_extend((raw >> PB_LINEAR11_EXP_SHIFT) &
+ PB_LINEAR11_EXP_MASK,
+ PB_LINEAR11_EXP_BITS);
+ s64 micro;
+
+ /* Engineering value = mantissa * 2^exponent, scaled to micro units. */
+ micro = (s64)mantissa * 1000000LL;
+ if (exponent >= 0)
+ micro <<= exponent;
+ else
+ micro >>= -exponent;
+ return micro;
+}
+
+s64 pmbus_reg2data_linear16(u16 raw, u8 vout_mode)
+{
+ int exponent;
+ s64 micro;
+
+ /*
+ * VOUT_MODE bits[7:5] = mode; bits[4:0] = parameter. Linear mode
+ * (000) treats bits[4:0] as the signed 5-bit exponent. For other
+ * modes the caller must dispatch elsewhere.
+ */
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) != PB_VOUT_MODE_LINEAR)
+ return 0;
+
+ exponent = pmbus_sign_extend(vout_mode & PB_VOUT_MODE_PARAM_MASK, 5);
+
+ /* Mantissa is unsigned 16-bit; scale to micro units. */
+ micro = (s64)raw * 1000000LL;
+ if (exponent >= 0)
+ micro <<= exponent;
+ else
+ micro >>= -exponent;
+ return micro;
+}
+
+s64 pmbus_reg2data_direct(s16 raw, int m, int b, int R)
+{
+ s64 acc;
+
+ if (m == 0)
+ return 0;
+
+ /*
+ * PMBus Part II sec 8.4: Y = (1/m) * (X * 10^-R - b)
+ *
+ * Pre scale acc to micro units so the final integer division by
+ * m absorbs the rounding loss into the least significant micro
+ * digit rather than into a coarser place.
+ */
+ acc = (s64)raw * 1000000LL;
+
+ /* Apply 10^-R: positive R means divide; negative R means multiply. */
+ while (R > 0) {
+ acc /= 10;
+ R--;
+ }
+ while (R < 0) {
+ acc *= 10;
+ R++;
+ }
+
+ /* Subtract the offset b, also in micro units. */
+ acc -= (s64)b * 1000000LL;
+
+ /* Final: divide by m. */
+ acc /= m;
+ return acc;
+}
+
+u16 pmbus_data2reg_linear16(s64 micro, u8 vout_mode)
+{
+ int exponent;
+ s64 raw;
+
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) != PB_VOUT_MODE_LINEAR)
+ return 0;
+
+ exponent = pmbus_sign_extend(vout_mode & PB_VOUT_MODE_PARAM_MASK, 5);
+
+ /* raw = micro / (2^exponent * 10^6). */
+ raw = micro;
+ if (exponent >= 0)
+ raw >>= exponent;
+ else
+ raw <<= -exponent;
+ raw /= 1000000LL;
+
+ if (raw < 0)
+ raw = 0;
+ if (raw > U16_MAX)
+ raw = U16_MAX;
+ return (u16)raw;
+}
+
+u16 pmbus_data2reg_direct(s64 micro, int m, int b, int R)
+{
+ s64 acc;
+
+ if (m == 0)
+ return 0;
+
+ /*
+ * Inverse of pmbus_reg2data_direct(): X = (m * Y + b) * 10^R.
+ * Work in micro units throughout: acc = m * Y_micro + b * 10^6,
+ * then scale by 10^R, finally divide by 10^6 to get the raw
+ * chip count. Order chosen to match the decoder's quantisation
+ * pattern so a round trip (data2reg then reg2data) returns the
+ * input within +/- one LSB.
+ */
+ acc = (s64)m * micro + (s64)b * 1000000LL;
+
+ while (R > 0) {
+ acc *= 10;
+ R--;
+ }
+ while (R < 0) {
+ acc /= 10;
+ R++;
+ }
+
+ acc /= 1000000LL;
+
+ /* PMBus 1.3 Part II sec 8.4 mandates a signed 16 bit raw value. */
+ if (acc > S16_MAX)
+ acc = S16_MAX;
+ if (acc < S16_MIN)
+ acc = S16_MIN;
+ return (u16)(s16)acc;
+}
+
+s64 pmbus_reg2data(const struct pmbus_driver_info *info,
+ enum pmbus_sensor_classes class,
+ u16 raw, u8 vout_mode)
+{
+ if (!info || class >= PSC_NUM_CLASSES)
+ return 0;
+
+ switch (info->format[class]) {
+ case pmbus_fmt_linear:
+ if (class == PSC_VOLTAGE_OUT)
+ return pmbus_reg2data_linear16(raw, vout_mode);
+ return pmbus_reg2data_linear11(raw);
+
+ case pmbus_fmt_direct:
+ return pmbus_reg2data_direct((s16)raw,
+ info->m[class],
+ info->b[class],
+ info->R[class]);
+
+ case pmbus_fmt_vid:
+ case pmbus_fmt_ieee754:
+ /*
+ * Not yet wired up. Add when a consumer lands. VID needs
+ * the per page vrm_version table from the kernel's
+ * pmbus_reg2data_vid(); IEEE754 needs the half precision
+ * decoder from pmbus_reg2data_ieee754().
+ */
+ return 0;
+ }
+
+ return 0;
+}
+
+int pmbus_read_byte(struct udevice *dev, u8 cmd, u8 *val)
+{
+ return dm_i2c_read(dev, cmd, val, 1);
+}
+
+int pmbus_read_word(struct udevice *dev, u8 cmd, u16 *val)
+{
+ u8 raw[2];
+ int ret;
+
+ ret = dm_i2c_read(dev, cmd, raw, 2);
+ if (ret)
+ return ret;
+ *val = (u16)raw[0] | ((u16)raw[1] << 8);
+ return 0;
+}
+
+int pmbus_write_byte(struct udevice *dev, u8 cmd, u8 val)
+{
+ return dm_i2c_write(dev, cmd, &val, 1);
+}
+
+int pmbus_write_word(struct udevice *dev, u8 cmd, u16 val)
+{
+ u8 raw[2];
+
+ raw[0] = (u8)(val & 0xff); /* PMBus words are little-endian */
+ raw[1] = (u8)(val >> 8);
+ return dm_i2c_write(dev, cmd, raw, 2);
+}
+
+int pmbus_read_string(struct udevice *dev, u8 cmd, char *out, int outsz,
+ bool reverse_bytes)
+{
+ u8 raw[PMBUS_MFR_STRING_MAX];
+ int ret, len, i;
+
+ if (outsz < 2)
+ return -EINVAL;
+
+ /* Stage 1: read the length byte. */
+ ret = dm_i2c_read(dev, cmd, raw, 1);
+ if (ret)
+ return ret;
+
+ len = raw[0];
+ if (len <= 0 || len > (int)sizeof(raw))
+ return -EBADMSG;
+ if (len > outsz - 1)
+ len = outsz - 1;
+
+ /* Stage 2: reread length + payload (some controllers mandate this). */
+ ret = dm_i2c_read(dev, cmd, raw, len + 1);
+ if (ret)
+ return ret;
+
+ if (reverse_bytes) {
+ for (i = 0; i < len; i++) {
+ u8 b = raw[len - i];
+
+ out[i] = isprint(b) ? (char)b : '.';
+ }
+ } else {
+ for (i = 0; i < len; i++) {
+ u8 b = raw[i + 1];
+
+ out[i] = isprint(b) ? (char)b : '.';
+ }
+ }
+ out[len] = '\0';
+ return len;
+}
+
+int pmbus_clear_faults(struct udevice *dev)
+{
+ return dm_i2c_write(dev, PMBUS_CLEAR_FAULTS, NULL, 0);
+}
+
+void pmbus_print_bits(u16 v, const struct pmbus_bit *tab)
+{
+ const struct pmbus_bit *t;
+ int first = 1;
+
+ if (v == 0) {
+ printf("clean");
+ return;
+ }
+ for (t = tab; t && t->name; t++) {
+ if (v & t->mask) {
+ printf("%s%s", first ? "" : "|", t->name);
+ first = 0;
+ }
+ }
+}
+
+void pmbus_print_status_bits(u8 reg, u16 v,
+ const struct pmbus_bit *std,
+ const struct pmbus_status_override *ovr)
+{
+ const struct pmbus_bit *s;
+ const struct pmbus_status_override *o;
+ int first = 1;
+
+ if (v == 0) {
+ printf("clean");
+ return;
+ }
+
+ /*
+ * Pass 1: walk the standard table in declared order so the
+ * printout retains the conventional bit-15-first ordering. For
+ * each set bit, prefer a chip override matching (reg, mask).
+ */
+ for (s = std; s && s->name; s++) {
+ const char *name;
+
+ if (!(v & s->mask))
+ continue;
+ name = s->name;
+ for (o = ovr; o && o->name; o++) {
+ if (o->reg == reg && o->mask == s->mask) {
+ name = o->name;
+ break;
+ }
+ }
+ printf("%s%s", first ? "" : "|", name);
+ first = 0;
+ }
+
+ /*
+ * Pass 2: print overrides whose mask is not in the standard
+ * table at all (chip-specific bit at a position the spec
+ * leaves RESERVED). These would otherwise be swallowed.
+ */
+ for (o = ovr; o && o->name; o++) {
+ bool in_std = false;
+
+ if (o->reg != reg)
+ continue;
+ if (!(v & o->mask))
+ continue;
+ for (s = std; s && s->name; s++) {
+ if (s->mask == o->mask) {
+ in_std = true;
+ break;
+ }
+ }
+ if (in_std)
+ continue;
+ printf("%s%s", first ? "" : "|", o->name);
+ first = 0;
+ }
+}
+
+/*
+ * Standard PMBus 1.3 status bit tables. Per-chip drivers may publish
+ * their own tables for vendor extended bits (e.g. NVM summary bits,
+ * DR MOS faults) but the standard layout below is the safe baseline.
+ *
+ * All tables are NULL terminated (`name = NULL` sentinel), matching
+ * the convention used elsewhere in U-Boot for driver tables.
+ */
+const struct pmbus_bit pmbus_status_word_bits[] = {
+ { PB_STATUS_VOUT, "VOUT" },
+ { PB_STATUS_IOUT_POUT, "IOUT_POUT" },
+ { PB_STATUS_INPUT, "INPUT" },
+ { PB_STATUS_WORD_MFR, "MFR" },
+ { PB_STATUS_POWER_GOOD_N, "PG#" },
+ { PB_STATUS_FANS, "FANS" },
+ { PB_STATUS_OTHER, "OTHER" },
+ { PB_STATUS_UNKNOWN, "UNKNOWN" },
+ { PB_STATUS_BUSY, "BUSY" },
+ { PB_STATUS_OFF, "OFF" },
+ { PB_STATUS_VOUT_OV, "VOUT_OV" },
+ { PB_STATUS_IOUT_OC, "IOUT_OC" },
+ { PB_STATUS_VIN_UV, "VIN_UV" },
+ { PB_STATUS_TEMPERATURE, "TEMP" },
+ { PB_STATUS_CML, "CML" },
+ { PB_STATUS_NONE_ABOVE, "NONE_ABOVE" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_vout_bits[] = {
+ { PB_VOLTAGE_OV_FAULT, "VOUT_OV_FAULT" },
+ { PB_VOLTAGE_OV_WARNING, "VOUT_OV_WARN" },
+ { PB_VOLTAGE_UV_WARNING, "VOUT_UV_WARN" },
+ { PB_VOLTAGE_UV_FAULT, "VOUT_UV_FAULT" },
+ { PB_VOLTAGE_VOUT_MAX_MIN_WARN, "VOUT_MAX_MIN_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_iout_bits[] = {
+ { PB_IOUT_OC_FAULT, "IOUT_OC_FAULT" },
+ { PB_IOUT_OC_LV_FAULT, "IOUT_OC_LV_FAULT" },
+ { PB_IOUT_OC_WARNING, "IOUT_OC_WARN" },
+ { PB_IOUT_UC_FAULT, "IOUT_UC_FAULT" },
+ { PB_CURRENT_SHARE_FAULT, "ISHARE_FAULT" },
+ { PB_POWER_LIMITING, "POWER_LIMITING" },
+ { PB_POUT_OP_FAULT, "POUT_OP_FAULT" },
+ { PB_POUT_OP_WARNING, "POUT_OP_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_input_bits[] = {
+ { PB_IIN_OC_FAULT, "IIN_OC_FAULT" },
+ { PB_IIN_OC_WARNING, "IIN_OC_WARN" },
+ { PB_PIN_OP_WARNING, "PIN_OP_WARN" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_temp_bits[] = {
+ { PB_TEMP_OT_FAULT, "OT_FAULT" },
+ { PB_TEMP_OT_WARNING, "OT_WARN" },
+ { PB_TEMP_UT_WARNING, "UT_WARN" },
+ { PB_TEMP_UT_FAULT, "UT_FAULT" },
+ { /* sentinel */ }
+};
+
+const struct pmbus_bit pmbus_status_cml_bits[] = {
+ { PB_CML_FAULT_INVALID_COMMAND, "INVALID_CMD" },
+ { PB_CML_FAULT_INVALID_DATA, "INVALID_DATA" },
+ { PB_CML_FAULT_PACKET_ERROR, "PEC" },
+ { PB_CML_FAULT_MEMORY, "MEM" },
+ { PB_CML_FAULT_PROCESSOR, "PROC" },
+ { PB_CML_FAULT_OTHER_COMM, "OTHER_COMM" },
+ { PB_CML_FAULT_OTHER_MEM_LOGIC, "OTHER_MEM_LOGIC" },
+ { /* sentinel */ }
+};
+
+/*
+ * Active device tracking + chip / vendor registries (consumed by the
+ * `pmbus` U-Boot CLI command in cmd/pmbus.c).
+ */
+
+#define PMBUS_MAX_CHIP_MATCHES 8
+#define PMBUS_MAX_VENDOR_HANDLERS 4
+
+static struct pmbus_active_dev pmbus_active_state;
+static const struct pmbus_chip_match *pmbus_chip_table[PMBUS_MAX_CHIP_MATCHES];
+static unsigned int pmbus_chip_table_n;
+static const struct pmbus_vendor_op *pmbus_vendor_table[PMBUS_MAX_VENDOR_HANDLERS];
+static unsigned int pmbus_vendor_table_n;
+
+const struct pmbus_active_dev *pmbus_active(void)
+{
+ return pmbus_active_state.valid ? &pmbus_active_state : NULL;
+}
+
+void pmbus_clear_active(void)
+{
+ memset(&pmbus_active_state, 0, sizeof(pmbus_active_state));
+}
+
+int pmbus_active_get_i2c(struct udevice **i2c_dev)
+{
+ struct udevice *bus;
+ int ret;
+
+ if (!pmbus_active_state.valid)
+ return -ENODEV;
+ ret = uclass_get_device_by_seq(UCLASS_I2C, pmbus_active_state.bus_seq, &bus);
+ if (ret)
+ return ret;
+ return i2c_get_chip(bus, pmbus_active_state.addr, 1, i2c_dev);
+}
+
+/* engineering value in micro units -> "I.FFF<unit>" (3 fractional digits) */
+static void pmbus_emit_micro(s64 micro, const char *unit)
+{
+ s64 abs_milli = (micro < 0 ? -micro : micro) / 1000LL;
+
+ printf("%lld.%03lld%s", (long long)(micro / 1000000LL),
+ (long long)(abs_milli % 1000LL), unit);
+}
+
+struct pmbus_telem_entry {
+ u8 reg;
+ const char *label;
+ enum pmbus_sensor_classes class;
+ const char *unit;
+};
+
+/*
+ * Telemetry register set, in print order. POUT is included so PSU
+ * class parts report input/output power; chips that do not implement
+ * a given command are skipped via pmbus_word_command_supported().
+ */
+static const struct pmbus_telem_entry pmbus_telem_table[] = {
+ { PMBUS_READ_VIN, "VIN ", PSC_VOLTAGE_IN, "V" },
+ { PMBUS_READ_VOUT, "VOUT", PSC_VOLTAGE_OUT, "V" },
+ { PMBUS_READ_IIN, "IIN ", PSC_CURRENT_IN, "A" },
+ { PMBUS_READ_IOUT, "IOUT", PSC_CURRENT_OUT, "A" },
+ { PMBUS_READ_POUT, "POUT", PSC_POWER, "W" },
+ { PMBUS_READ_TEMPERATURE_1, "TEMP", PSC_TEMPERATURE, "C" },
+};
+
+bool pmbus_word_command_supported(struct udevice *dev, u8 reg)
+{
+ u8 cml_before = 0, cml_after = 0;
+ bool have_cml;
+ u16 w;
+
+ have_cml = !pmbus_read_byte(dev, PMBUS_STATUS_CML, &cml_before);
+
+ if (pmbus_read_word(dev, reg, &w))
+ return false; /* NAK: unsupported command not ACKed */
+
+ if (have_cml && !(cml_before & PB_CML_FAULT_INVALID_COMMAND) &&
+ !pmbus_read_byte(dev, PMBUS_STATUS_CML, &cml_after) &&
+ (cml_after & PB_CML_FAULT_INVALID_COMMAND))
+ return false; /* ACKed but chip raised INVALID_COMMAND */
+
+ return true;
+}
+
+/* Telemetry of the currently selected page. */
+static void pmbus_print_telemetry_page(struct udevice *chip,
+ const struct pmbus_active_dev *act)
+{
+ u8 vout_mode = 0;
+ unsigned int i;
+
+ /*
+ * On a read failure vout_mode stays 0 (LINEAR, exponent 0). That is
+ * a silent mis-scale of every VOLTAGE_OUT reading, so make the
+ * fallback visible rather than printing a wrong voltage as if good.
+ */
+ if (pmbus_read_byte(chip, PMBUS_VOUT_MODE, &vout_mode))
+ printf(" (VOUT_MODE read failed; VOUT decode assumes LINEAR exp 0)\n");
+
+ for (i = 0; i < ARRAY_SIZE(pmbus_telem_table); i++) {
+ const struct pmbus_telem_entry *e = &pmbus_telem_table[i];
+ u16 raw = 0;
+
+ /*
+ * Class gating. A chip driver that declares classes_present
+ * lists exactly the sensors it implements (kernel-style
+ * per-chip sensor set), so unlisted classes are skipped
+ * silently -- this is what hides the MPS buck's uncalibrated
+ * POUT / IIN. A generic / undeclared device instead gets a
+ * live capability probe per class.
+ */
+ if (act->info && act->info->classes_present) {
+ if (!(act->info->classes_present & BIT(e->class)))
+ continue;
+ } else if (!pmbus_word_command_supported(chip, e->reg)) {
+ printf(" %s : (not supported)\n", e->label);
+ continue;
+ }
+
+ if (pmbus_read_word(chip, e->reg, &raw)) {
+ printf(" %s : (read failed)\n", e->label);
+ continue;
+ }
+
+ printf(" %s : raw=0x%04x ", e->label, raw);
+ if (act->info) {
+ u16 dec = raw;
+
+ /*
+ * Some DIRECT format parts (e.g. MPS) report
+ * temperature as 1 degC/LSB in the low byte only;
+ * mask there. LINEAR temperatures use all 16 bits
+ * and must NOT be masked.
+ */
+ if (e->class == PSC_TEMPERATURE &&
+ act->info->format[PSC_TEMPERATURE] == pmbus_fmt_direct)
+ dec = raw & 0x00ff;
+
+ pmbus_emit_micro(pmbus_reg2data(act->info, e->class,
+ dec, vout_mode),
+ e->unit);
+ } else if (e->class == PSC_VOLTAGE_OUT) {
+ pmbus_emit_micro(pmbus_reg2data_linear16(raw, vout_mode),
+ e->unit);
+ } else {
+ pmbus_emit_micro(pmbus_reg2data_linear11(raw), e->unit);
+ printf(" (LINEAR11 fallback)");
+ }
+ printf("\n");
+ }
+}
+
+void pmbus_print_telemetry(struct udevice *chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+ int npages, p;
+ u8 zero = 0;
+
+ if (!act)
+ return;
+
+ /*
+ * Multi-rail parts (PSU bricks) expose one rail per PMBUS_PAGE.
+ * Chip drivers set pmbus_driver_info.pages; the generic driver
+ * takes it from the DT `pmbus,num-pages` (default 1). We always
+ * write PMBUS_PAGE before reading a page -- including page 0 --
+ * because a device may power up selected on a different page, which
+ * is what made the 48V PSU read all-zeros before. Only valid pages
+ * (0..npages-1) are ever written, so we never induce the
+ * out-of-range-PAGE STATUS_CML fault and the device's sticky fault
+ * log is left untouched (no CLEAR_FAULTS, no scrubbing).
+ */
+ npages = (act->info && act->info->pages > 0) ? act->info->pages : 1;
+
+ for (p = 0; p < npages; p++) {
+ u8 pg = (u8)p;
+
+ if (dm_i2c_write(chip, PMBUS_PAGE, &pg, 1)) {
+ printf(" [page %d] PAGE select failed\n", p);
+ continue;
+ }
+ if (npages > 1)
+ printf(" [page %d]\n", p);
+ pmbus_print_telemetry_page(chip, act);
+ }
+
+ if (npages > 1)
+ dm_i2c_write(chip, PMBUS_PAGE, &zero, 1); /* leave on page 0 */
+}
+
+void pmbus_print_status_word(struct udevice *chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+ const struct pmbus_status_override *ovr =
+ (act && act->info) ? act->info->status_overrides : NULL;
+ u16 word = 0;
+
+ if (pmbus_read_word(chip, PMBUS_STATUS_WORD, &word)) {
+ printf(" STATUS_WORD (79h) = (read failed)\n");
+ return;
+ }
+ printf(" STATUS_WORD (79h) = 0x%04x [", word);
+ pmbus_print_status_bits(PMBUS_STATUS_WORD, word,
+ pmbus_status_word_bits, ovr);
+ printf("]\n");
+}
+
+static const struct pmbus_chip_match *pmbus_match_mfr(const char *id)
+{
+ unsigned int i;
+
+ if (!id || !id[0])
+ return NULL;
+ for (i = 0; i < pmbus_chip_table_n; i++) {
+ const struct pmbus_chip_match *m = pmbus_chip_table[i];
+ size_t plen = strlen(m->mfr_id);
+
+ if (strlen(id) >= plen && !strncmp(id, m->mfr_id, plen))
+ return m;
+ }
+ return NULL;
+}
+
+/*
+ * Walk UCLASS_REGULATOR looking for a regulator whose I2C parent
+ * bus seq + DT reg address match the requested (bus_seq, addr).
+ * Returns the regulator-name (uclass plat .name) on hit, or NULL if
+ * no UCLASS_REGULATOR device matches (chip not bound through DT, or
+ * CONFIG_DM_REGULATOR disabled).
+ */
+static const char *pmbus_lookup_regname(int bus_seq, u8 addr)
+{
+ struct uclass *uc;
+ struct udevice *r;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR))
+ return NULL;
+
+ if (uclass_get(UCLASS_REGULATOR, &uc))
+ return NULL;
+ uclass_foreach_dev(r, uc) {
+ struct dm_regulator_uclass_plat *up;
+ struct udevice *parent = dev_get_parent(r);
+ int ra;
+
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ continue;
+ if (dev_seq(parent) != bus_seq)
+ continue;
+ ra = dev_read_addr(r);
+ if (ra < 0 || (u8)ra != addr)
+ continue;
+ up = dev_get_uclass_plat(r);
+ if (up && up->name)
+ return up->name;
+ return r->name;
+ }
+ return NULL;
+}
+
+int pmbus_set_active(int bus_seq, u8 addr)
+{
+ const struct pmbus_chip_match *match = NULL;
+ struct udevice *bus, *chip;
+ char id_fwd[PMBUS_MFR_STRING_MAX] = "";
+ char id_rev[PMBUS_MFR_STRING_MAX] = "";
+ const char *rname;
+ int ret;
+
+ pmbus_clear_active();
+
+ ret = uclass_get_device_by_seq(UCLASS_I2C, bus_seq, &bus);
+ if (ret)
+ return ret;
+ ret = i2c_get_chip(bus, addr, 1, &chip);
+ if (ret)
+ return ret;
+
+ pmbus_active_state.bus_seq = bus_seq;
+ pmbus_active_state.addr = addr;
+
+ /*
+ * Probe MFR_ID in both byte orders. Spec compliant chips return
+ * "MPS" / "TI" / etc. in the natural reading (forward); MPS NVM
+ * personalities store the string LSB first and need the reverse
+ * read. Chip table entries declare which one is canonical for
+ * the chip family they describe.
+ */
+ if (pmbus_read_string(chip, PMBUS_MFR_ID, id_fwd, sizeof(id_fwd), false) < 0)
+ id_fwd[0] = '\0';
+ if (pmbus_read_string(chip, PMBUS_MFR_ID, id_rev, sizeof(id_rev), true) < 0)
+ id_rev[0] = '\0';
+
+ match = pmbus_match_mfr(id_fwd);
+ if (match && !match->mfr_id_reverse) {
+ strlcpy(pmbus_active_state.mfr_id, id_fwd,
+ sizeof(pmbus_active_state.mfr_id));
+ } else {
+ match = pmbus_match_mfr(id_rev);
+ if (match && match->mfr_id_reverse) {
+ strlcpy(pmbus_active_state.mfr_id, id_rev,
+ sizeof(pmbus_active_state.mfr_id));
+ } else {
+ /* No registered match; cache the forward read as best effort. */
+ strlcpy(pmbus_active_state.mfr_id,
+ id_fwd[0] ? id_fwd : id_rev,
+ sizeof(pmbus_active_state.mfr_id));
+ }
+ }
+
+ if (match) {
+ pmbus_active_state.info = match->info;
+ if (match->vendor)
+ strlcpy(pmbus_active_state.vendor, match->vendor,
+ sizeof(pmbus_active_state.vendor));
+ }
+
+ /*
+ * MFR_MODEL / MFR_REVISION are best effort. Use the same byte
+ * order the matched chip declared; if nothing matched, use the
+ * forward order.
+ */
+ {
+ bool reverse = match && match->mfr_id_reverse;
+
+ pmbus_read_string(chip, PMBUS_MFR_MODEL,
+ pmbus_active_state.mfr_model,
+ sizeof(pmbus_active_state.mfr_model), reverse);
+ pmbus_read_string(chip, PMBUS_MFR_REVISION,
+ pmbus_active_state.mfr_revision,
+ sizeof(pmbus_active_state.mfr_revision), reverse);
+ }
+
+ rname = pmbus_lookup_regname(bus_seq, addr);
+ if (rname)
+ strlcpy(pmbus_active_state.name, rname,
+ sizeof(pmbus_active_state.name));
+
+ pmbus_active_state.valid = true;
+ return 0;
+}
+
+int pmbus_register_chip(const struct pmbus_chip_match *match)
+{
+ if (!match || !match->mfr_id)
+ return -EINVAL;
+ if (pmbus_chip_table_n >= PMBUS_MAX_CHIP_MATCHES)
+ return -ENOSPC;
+ pmbus_chip_table[pmbus_chip_table_n++] = match;
+ return 0;
+}
+
+int pmbus_register_vendor_handler(const struct pmbus_vendor_op *op)
+{
+ if (!op || !op->vendor || !op->handler)
+ return -EINVAL;
+ if (pmbus_vendor_table_n >= PMBUS_MAX_VENDOR_HANDLERS)
+ return -ENOSPC;
+ pmbus_vendor_table[pmbus_vendor_table_n++] = op;
+ return 0;
+}
+
+const struct pmbus_vendor_op *pmbus_lookup_vendor(const char *vendor)
+{
+ unsigned int i;
+
+ if (!vendor)
+ return NULL;
+ for (i = 0; i < pmbus_vendor_table_n; i++)
+ if (!strcmp(pmbus_vendor_table[i]->vendor, vendor))
+ return pmbus_vendor_table[i];
+ return NULL;
+}
+
+unsigned int pmbus_vendor_count(void)
+{
+ return pmbus_vendor_table_n;
+}
+
+const struct pmbus_vendor_op *pmbus_vendor_at(unsigned int i)
+{
+ return i < pmbus_vendor_table_n ? pmbus_vendor_table[i] : NULL;
+}
+
+int pmbus_resolve_by_name(const char *name, int *bus_seq, u8 *addr)
+{
+ struct udevice *reg;
+ struct udevice *parent;
+ int ret;
+ int a;
+
+ if (!IS_ENABLED(CONFIG_DM_REGULATOR))
+ return -ENOSYS;
+
+ if (!name || !bus_seq || !addr)
+ return -EINVAL;
+
+ ret = regulator_get_by_platname(name, ®);
+ if (ret)
+ return ret;
+
+ parent = dev_get_parent(reg);
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ return -ENODEV;
+
+ a = dev_read_addr(reg);
+ if (a < 0 || a > 0x7f)
+ return -EINVAL;
+
+ *bus_seq = dev_seq(parent);
+ *addr = (u8)a;
+ return 0;
+}
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 19:56 ` [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
@ 2026-07-02 20:07 ` Vincent Jardin
2026-07-02 20:14 ` [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
` (4 subsequent siblings)
6 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 20:07 UTC (permalink / raw)
To: u-boot
Cc: Vincent Jardin, Tom Rini, Jaehoon Chung, Peng Fan, Neil Armstrong,
Simon Glass, Kory Maincent, Kuan-Wei Chiu, Raymond Mao,
Quentin Schulz, Stefan Roese, Philip Molloy, Jerome Forissier,
Anshul Dalal, Heinrich Schuchardt, Julien Masson, Bo-Chen Chen,
David Lechner, Macpaul Lin
PMBus regulators differ in numeric formats and quirks, not in how they
are driven. Share that common behaviour as a regulator-uclass adapter
so chip drivers and the pmbus CLI do not each reimplement the decode
and transport, and add a catch-all driver on compatible = "pmbus" for
compliant chips that have no dedicated driver yet.
Gated by CONFIG_DM_REGULATOR_PMBUS_HELPER and
CONFIG_DM_REGULATOR_PMBUS_GENERIC.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
MAINTAINERS | 3 +
drivers/power/regulator/Kconfig | 24 ++
drivers/power/regulator/Makefile | 2 +
drivers/power/regulator/pmbus_generic.c | 90 +++++++
drivers/power/regulator/pmbus_helper.c | 315 ++++++++++++++++++++++++
drivers/power/regulator/pmbus_helper.h | 90 +++++++
include/pmbus.h | 37 +++
lib/pmbus.c | 17 ++
8 files changed, 578 insertions(+)
create mode 100644 drivers/power/regulator/pmbus_generic.c
create mode 100644 drivers/power/regulator/pmbus_helper.c
create mode 100644 drivers/power/regulator/pmbus_helper.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 39e333f8f70..123ea9ed3ed 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1585,6 +1585,9 @@ M: Vincent Jardin <vjardin@free.fr>
S: Maintained
F: cmd/pmbus.c
F: doc/develop/pmbus.rst
+F: drivers/power/regulator/pmbus_generic.c
+F: drivers/power/regulator/pmbus_helper.c
+F: drivers/power/regulator/pmbus_helper.h
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index ca5de5b8726..5b1a9c3f991 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -557,3 +557,27 @@ config DM_REGULATOR_MT6359
MediaTek MT6359 PMIC.
This driver supports the control of different power rails of device
through regulator interface.
+
+config DM_REGULATOR_PMBUS_HELPER
+ bool "Shared regulator helpers for PMBus chip drivers"
+ depends on DM_REGULATOR && PMBUS && DM_I2C
+ help
+ Provide shared get_value / set_value / get_enable / set_enable
+ operations for UCLASS_REGULATOR drivers that bind PMBus 1.x
+ compliant voltage regulators. Per chip drivers
+ (mps,mpq8785, lltc,ltc3882, ...) consume this helper to avoid
+ duplicating the LINEAR16 / DIRECT decoder dispatch and the
+ VOUT_MODE / VOUT_COMMAND / OPERATION transport sequences.
+
+config DM_REGULATOR_PMBUS_GENERIC
+ bool "Generic PMBus 1.x regulator driver (compatible=\"pmbus\")"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Catch all UCLASS_REGULATOR driver bound to compatible = "pmbus".
+ Auto detects the VOUT numeric format from the chip's VOUT_MODE
+ register and exposes telemetry plus voltage set / get against
+ the standard PMBus 1.x command codes. Use this for PMBus
+ compliant chips that have no per chip driver yet; promote to a
+ per chip driver only when chip specific quirks (vendor
+ registers, VID coercion, ADDR pin auto promotion, non standard
+ m / b / R coefficients) need handling.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 36a84e7cd71..b084e9ac4bc 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -49,3 +49,5 @@ obj-$(CONFIG_REGULATOR_RZG2L_USBPHY) += rzg2l-usbphy-regulator.o
obj-$(CONFIG_$(PHASE_)DM_REGULATOR_CPCAP) += cpcap_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6357) += mt6357_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
+obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
+obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
diff --git a/drivers/power/regulator/pmbus_generic.c b/drivers/power/regulator/pmbus_generic.c
new file mode 100644
index 00000000000..6ba50ce08f8
--- /dev/null
+++ b/drivers/power/regulator/pmbus_generic.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Generic PMBus 1.x compatible voltage regulator driver.
+ *
+ * Catch all driver bound to compatible = "pmbus" for chips that have
+ * no per chip driver under drivers/power/regulator/. The probe path
+ * detects the VOUT numeric format from VOUT_MODE bits[7:5]:
+ *
+ * - 0 LINEAR16 with the exponent supplied via VOUT_MODE bits[4:0]
+ * - 1 VID; mapped to pmbus_fmt_vid (decoder returns 0 today; per
+ * chip driver still required to plug a VID table)
+ * - 2 DIRECT; default coefficients m=1, b=0, R=0 (per chip
+ * coefficients arrive via PMBUS_QUERY / PMBUS_COEFFICIENTS,
+ * not yet consumed by U-Boot; values may need a per chip
+ * driver if telemetry numbers are wrong)
+ * - 3 IEEE754; mapped to pmbus_fmt_ieee754 (decoder returns 0
+ * today; per chip driver required)
+ *
+ * Other sensor classes (VIN, IIN, IOUT, TEMPERATURE) default to
+ * LINEAR which is the spec baseline for compliant chips. If an
+ * operator sees wrong telemetry numbers on this driver, the answer
+ * is to write a per chip driver with the correct format[] / m / b / R.
+ *
+ * Adapted in spirit from linux/drivers/hwmon/pmbus/pmbus.c (the
+ * kernel's generic probe driver). The U-Boot version drops the
+ * page count auto detection (most generic compliant parts are
+ * single rail; multi rail chips are quirky enough to need a per
+ * chip driver) and the kernel hwmon publication layers.
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+struct pmbus_generic_priv {
+ struct pmbus_regulator_priv base; /* must be first */
+ struct pmbus_driver_info info;
+};
+
+static int pmbus_generic_probe(struct udevice *dev)
+{
+ struct pmbus_generic_priv *gpriv = dev_get_priv(dev);
+ struct pmbus_driver_info *info = &gpriv->info;
+ enum pmbus_sensor_classes c;
+ int ret;
+
+ info->pages = 1;
+ for (c = 0; c < PSC_NUM_CLASSES; c++) {
+ info->format[c] = pmbus_fmt_linear;
+ info->m[c] = 0;
+ info->b[c] = 0;
+ info->R[c] = 0;
+ }
+
+ ret = pmbus_regulator_probe_common(dev, info, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * Avoid reading non supported pages to avoid device's sticky
+ * status.
+ */
+ info->pages = dev_read_u32_default(dev, "pmbus,num-pages", 1);
+ if (info->pages < 1)
+ info->pages = 1;
+
+ pmbus_regulator_identify_vout(gpriv->base.i2c_dev, info);
+
+ return 0;
+}
+
+static const struct udevice_id pmbus_generic_ids[] = {
+ { .compatible = "pmbus" },
+ { }
+};
+
+U_BOOT_DRIVER(pmbus_generic_regulator) = {
+ .name = "pmbus_generic_regulator",
+ .id = UCLASS_REGULATOR,
+ .of_match = pmbus_generic_ids,
+ .probe = pmbus_generic_probe,
+ .ops = &pmbus_regulator_ops,
+ .priv_auto = sizeof(struct pmbus_generic_priv),
+};
diff --git a/drivers/power/regulator/pmbus_helper.c b/drivers/power/regulator/pmbus_helper.c
new file mode 100644
index 00000000000..4763470442d
--- /dev/null
+++ b/drivers/power/regulator/pmbus_helper.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Shared UCLASS_REGULATOR operations over the PMBus 1.x framework.
+ * See pmbus_helper.h for the API surface and doc/develop/pmbus.rst
+ * for the porting guide.
+ *
+ * No code in this file may reference a specific chip family or
+ * board. Chip specific quirks (vendor registers, VID coercion,
+ * ADDR pin auto promotion, byte reversed MFR strings, etc.) belong
+ * in the per chip driver under drivers/power/regulator/<chip>.c.
+ */
+
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/types.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+static int pmbus_regulator_select_page(struct pmbus_regulator_priv *priv)
+{
+ u8 p;
+
+ if (priv->page <= 0)
+ return 0;
+ p = (u8)priv->page;
+ return dm_i2c_write(priv->i2c_dev, PMBUS_PAGE, &p, 1);
+}
+
+static int pmbus_regulator_get_value(struct udevice *dev)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 vout_mode = 0;
+ u16 raw = 0;
+ s64 uv;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ pmbus_read_byte(priv->i2c_dev, PMBUS_VOUT_MODE, &vout_mode);
+ if (pmbus_read_word(priv->i2c_dev, PMBUS_READ_VOUT, &raw))
+ return -EIO;
+
+ if (priv->info)
+ uv = pmbus_reg2data(priv->info, PSC_VOLTAGE_OUT, raw, vout_mode);
+ else
+ uv = pmbus_reg2data_linear16(raw, vout_mode);
+
+ if (uv > INT_MAX)
+ uv = INT_MAX;
+ if (uv < INT_MIN)
+ uv = INT_MIN;
+ return (int)uv;
+}
+
+static int pmbus_regulator_set_value(struct udevice *dev, int uV)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 vout_mode = 0;
+ u8 buf[2];
+ u16 raw;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_VOUT_MODE, &vout_mode))
+ return -EIO;
+
+ /*
+ * Dispatch on the chip's VOUT_MODE selector. LINEAR16 and DIRECT
+ * are wired today; VID and IEEE754 return -ENOSYS until their
+ * encoders land. For DIRECT, the m / b / R triple comes from the
+ * chip's pmbus_driver_info[PSC_VOLTAGE_OUT]; if the per chip
+ * driver did not populate them, the encoder cannot run.
+ */
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ raw = pmbus_data2reg_linear16((s64)uV, vout_mode);
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ if (!priv->info ||
+ priv->info->format[PSC_VOLTAGE_OUT] != pmbus_fmt_direct)
+ return -ENODATA;
+ raw = pmbus_data2reg_direct((s64)uV,
+ priv->info->m[PSC_VOLTAGE_OUT],
+ priv->info->b[PSC_VOLTAGE_OUT],
+ priv->info->R[PSC_VOLTAGE_OUT]);
+ break;
+ default:
+ return -ENOSYS;
+ }
+
+ buf[0] = (u8)(raw & 0xff);
+ buf[1] = (u8)((raw >> 8) & 0xff);
+ return dm_i2c_write(priv->i2c_dev, PMBUS_VOUT_COMMAND, buf, 2);
+}
+
+static int pmbus_regulator_get_enable(struct udevice *dev)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 op = 0;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_OPERATION, &op))
+ return -EIO;
+ return (op & PB_OPERATION_ON) ? 1 : 0;
+}
+
+static int pmbus_regulator_set_enable(struct udevice *dev, bool enable)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 op = 0;
+ int ret;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_byte(priv->i2c_dev, PMBUS_OPERATION, &op))
+ return -EIO;
+
+ if (enable)
+ op |= PB_OPERATION_ON;
+ else
+ op &= (u8)~PB_OPERATION_ON;
+ return dm_i2c_write(priv->i2c_dev, PMBUS_OPERATION, &op, 1);
+}
+
+const struct dm_regulator_ops pmbus_regulator_ops = {
+ .get_value = pmbus_regulator_get_value,
+ .set_value = pmbus_regulator_set_value,
+ .get_enable = pmbus_regulator_get_enable,
+ .set_enable = pmbus_regulator_set_enable,
+};
+
+int pmbus_regulator_read_temp(struct udevice *reg_dev, int *temp_mc)
+{
+ struct pmbus_regulator_priv *priv;
+ u16 raw = 0;
+ s64 udeg;
+ int ret;
+
+ if (!reg_dev || !temp_mc)
+ return -EINVAL;
+ priv = dev_get_priv(reg_dev);
+ if (!priv || !priv->i2c_dev)
+ return -ENODEV;
+
+ ret = pmbus_regulator_select_page(priv);
+ if (ret)
+ return ret;
+ if (pmbus_read_word(priv->i2c_dev, PMBUS_READ_TEMPERATURE_1, &raw))
+ return -EIO;
+
+ /*
+ * vout_mode is meaningless for the temperature class. With a
+ * chip info record the dispatcher honours its per-class format
+ * (DIRECT m/b/R for MPS, LINEAR11 for spec-compliant parts);
+ * without one, fall back to the PMBus 1.x standard LINEAR11.
+ */
+ if (priv->info)
+ udeg = pmbus_reg2data(priv->info, PSC_TEMPERATURE, raw, 0);
+ else
+ udeg = pmbus_reg2data_linear11(raw);
+
+ *temp_mc = (int)(udeg / 1000);
+ return 0;
+}
+
+enum pmbus_data_format
+pmbus_regulator_identify_vout(struct udevice *i2c_dev,
+ struct pmbus_driver_info *info)
+{
+ u8 vout_mode = 0;
+
+ if (pmbus_read_byte(i2c_dev, PMBUS_VOUT_MODE, &vout_mode))
+ return info->format[PSC_VOLTAGE_OUT];
+
+ switch (vout_mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear;
+ break;
+ case PB_VOUT_MODE_VID:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_vid;
+ break;
+ case PB_VOUT_MODE_DIRECT:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct;
+ info->m[PSC_VOLTAGE_OUT] = 1;
+ info->b[PSC_VOLTAGE_OUT] = 0;
+ info->R[PSC_VOLTAGE_OUT] = 0;
+ break;
+ case PB_VOUT_MODE_IEEE754:
+ info->format[PSC_VOLTAGE_OUT] = pmbus_fmt_ieee754;
+ break;
+ default:
+ break;
+ }
+ return info->format[PSC_VOLTAGE_OUT];
+}
+
+const struct pmbus_driver_info *pmbus_regulator_info_by_addr(int bus_seq,
+ u8 addr)
+{
+ struct uclass *uc;
+ struct udevice *r;
+
+ if (uclass_get(UCLASS_REGULATOR, &uc))
+ return NULL;
+
+ uclass_foreach_dev(r, uc) {
+ struct udevice *parent = dev_get_parent(r);
+ struct pmbus_regulator_priv *priv;
+ int ra;
+
+ if (!parent || device_get_uclass_id(parent) != UCLASS_I2C)
+ continue;
+ if (dev_seq(parent) != bus_seq)
+ continue;
+ ra = dev_read_addr(r);
+ if (ra < 0 || (u8)ra != addr)
+ continue;
+
+ /*
+ * Address matches. Only chips driven through this helper
+ * carry a pmbus_regulator_priv at the head of their priv;
+ * identify them by their shared ops vector so we never
+ * misread a foreign regulator's private layout.
+ */
+ if (!r->driver || r->driver->ops != &pmbus_regulator_ops)
+ return NULL;
+ if (device_probe(r))
+ return NULL;
+ priv = dev_get_priv(r);
+ return priv ? priv->info : NULL;
+ }
+ return NULL;
+}
+
+/*
+ * Spawn the generic UCLASS_THERMAL companion (drivers/thermal/
+ * pmbus_thermal.c) as a child of this regulator so READ_TEMPERATURE_1
+ * is reachable through the standard `temperature list` / `temperature
+ * get` interface. Named "<regulator-name>-temp" so several PMBus rails
+ * on one board produce distinct, descriptive device names. Failure is
+ * non-fatal: the chip still works as a UCLASS_REGULATOR.
+ */
+static void pmbus_regulator_bind_thermal(struct udevice *dev)
+{
+ struct udevice *therm;
+ const char *rname;
+ char name[48];
+
+ if (!IS_ENABLED(CONFIG_PMBUS_THERMAL))
+ return;
+ if (device_bind_driver(dev, "pmbus_thermal", "pmbus-temp", &therm))
+ return;
+ rname = dev_read_string(dev, "regulator-name");
+ snprintf(name, sizeof(name), "%s-temp", rname ? rname : dev->name);
+ device_set_name(therm, name);
+}
+
+int pmbus_regulator_probe_common(struct udevice *dev,
+ const struct pmbus_driver_info *info,
+ int page)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ int chip_addr;
+ int ret;
+
+ chip_addr = dev_read_addr(dev);
+ if (chip_addr < 0)
+ return -EINVAL;
+
+ ret = i2c_get_chip(dev_get_parent(dev), (u32)chip_addr, 1, &priv->i2c_dev);
+ if (ret)
+ return ret;
+
+ priv->info = info;
+ priv->page = page;
+
+ if (page > 0) {
+ u8 p = (u8)page;
+
+ ret = dm_i2c_write(priv->i2c_dev, PMBUS_PAGE, &p, 1);
+ if (ret)
+ return ret;
+ }
+
+ pmbus_regulator_bind_thermal(dev);
+ return 0;
+}
+
+int pmbus_regulator_apply_voltage_scale(struct udevice *dev,
+ u32 fb_divider_permille)
+{
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ u8 buf[2];
+
+ if (fb_divider_permille == 0)
+ return 0;
+ buf[0] = (u8)(fb_divider_permille & 0xff);
+ buf[1] = (u8)((fb_divider_permille >> 8) & 0xff);
+ return dm_i2c_write(priv->i2c_dev, PMBUS_VOUT_SCALE_LOOP, buf, 2);
+}
diff --git a/drivers/power/regulator/pmbus_helper.h b/drivers/power/regulator/pmbus_helper.h
new file mode 100644
index 00000000000..82f263cd513
--- /dev/null
+++ b/drivers/power/regulator/pmbus_helper.h
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Shared UCLASS_REGULATOR ops for PMBus 1.x voltage regulator chips.
+ *
+ * Per chip drivers under drivers/power/regulator/<chip>.c bind a
+ * vendor,chip compatible from DT and call pmbus_regulator_probe_common()
+ * in their .probe. They install pmbus_regulator_ops as the .ops vector;
+ * the helper handles VOUT_MODE / READ_VOUT / VOUT_COMMAND / OPERATION
+ * via the tree level <pmbus.h> framework.
+ *
+ * Per chip drivers retain control of identify hooks (VOUT_MODE based
+ * format selection), chip specific quirks (vendor registers, ADDR pin
+ * auto promotion), and DT property handling (e.g. MPS
+ * mps,vout-fb-divider-ratio-permille).
+ */
+
+#ifndef _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_
+#define _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_
+
+#include <linux/types.h>
+#include <pmbus.h>
+
+struct udevice;
+struct dm_regulator_ops;
+
+/*
+ * Per chip private state. The first field of every per chip driver's
+ * priv_auto must be (or contain at offset 0) a struct
+ * pmbus_regulator_priv so the shared ops vector can recover it via
+ * dev_get_priv(dev).
+ *
+ * i2c_dev chip handle obtained from dev->parent at probe time
+ * (the parent must be a UCLASS_I2C bus).
+ * page PMBUS_PAGE selector for multi rail chips. Single rail
+ * chips set page = 0; the helper writes PMBUS_PAGE only
+ * when page > 0 to avoid wasted bus traffic on single
+ * rail parts.
+ * info pointer to the chip's pmbus_driver_info; consumed by
+ * pmbus_reg2data() / pmbus_data2reg_linear16() to pick
+ * the right format[] / m / b / R coefficients.
+ */
+struct pmbus_regulator_priv {
+ struct udevice *i2c_dev;
+ int page;
+ const struct pmbus_driver_info *info;
+};
+
+extern const struct dm_regulator_ops pmbus_regulator_ops;
+
+/*
+ * Per chip probe glue. Reads `reg` from DT, gets the I2C chip handle
+ * from dev->parent, populates priv->i2c_dev / page / info, and writes
+ * PMBUS_PAGE if page > 0. Per chip drivers call this in their .probe
+ * before any chip specific identification.
+ */
+int pmbus_regulator_probe_common(struct udevice *dev,
+ const struct pmbus_driver_info *info,
+ int page);
+
+/*
+ * Optional helper for per chip drivers that honour an external
+ * feedback divider DT property (e.g. MPS mps,vout-fb-divider-ratio-
+ * permille). Writes the supplied ratio to PMBUS_VOUT_SCALE_LOOP at
+ * probe time. fb_divider_permille == 0 leaves the chip default.
+ */
+int pmbus_regulator_apply_voltage_scale(struct udevice *dev,
+ u32 fb_divider_permille);
+
+/*
+ * Read PMBUS_VOUT_MODE and set info->format[PSC_VOLTAGE_OUT] from its
+ * mode selector bits[7:5] per PMBus 1.3 Part II sec 8.3:
+ * LINEAR -> pmbus_fmt_linear
+ * VID -> pmbus_fmt_vid
+ * DIRECT -> pmbus_fmt_direct (default coefficients m=1, b=0, R=0)
+ * IEEE754 -> pmbus_fmt_ieee754
+ *
+ * The single place that knows the VOUT_MODE bit layout; both the
+ * generic regulator and per chip drivers call it so they never
+ * re-implement the switch. Returns the selected format so a chip
+ * driver can post-adjust a quirk (e.g. MPS encodes VOUT in DIRECT
+ * with m=64 R=1 even when VOUT_MODE reports VID). On a VOUT_MODE read
+ * failure the format is left unchanged and the prior value is returned.
+ */
+enum pmbus_data_format
+pmbus_regulator_identify_vout(struct udevice *i2c_dev,
+ struct pmbus_driver_info *info);
+
+#endif /* _DRIVERS_POWER_REGULATOR_PMBUS_HELPER_H_ */
diff --git a/include/pmbus.h b/include/pmbus.h
index 969108e5b53..3ac82465190 100644
--- a/include/pmbus.h
+++ b/include/pmbus.h
@@ -464,6 +464,43 @@ bool pmbus_word_command_supported(struct udevice *dev, u8 reg);
void pmbus_print_telemetry(struct udevice *chip);
void pmbus_print_status_word(struct udevice *chip);
+/*
+ * Regulator -> thermal bridge.
+ *
+ * Read READ_TEMPERATURE_1 (8Dh) from a UCLASS_REGULATOR device that
+ * was bound by a pmbus_helper based chip driver, decode it through
+ * the chip's pmbus_driver_info (so the MPS DIRECT 1 degC/LSB quirk
+ * and the standard LINEAR11 encoding are both handled), select the
+ * regulator's PAGE first on multi rail parts, and return the result
+ * in millidegrees Celsius.
+ *
+ * This is what the generic drivers/thermal/pmbus_thermal.c companion
+ * calls on its parent; keeping the decode here avoids exposing the
+ * regulator-private pmbus_regulator_priv layout to other subsystems.
+ *
+ * Returns 0 on success, or a negative errno (-ENODEV if reg is not a
+ * probed pmbus regulator, -EIO on bus error).
+ */
+int pmbus_regulator_read_temp(struct udevice *reg_dev, int *temp_mc);
+
+/*
+ * Look up the pmbus_driver_info of a probed UCLASS_REGULATOR device at
+ * (bus_seq, addr) that is driven by a pmbus_helper based chip driver
+ * (mpq8785, pmbus_generic, ...). Probes the device so its identify
+ * hook has run and format[] is populated, then returns its
+ * driver_info. Returns NULL if no such regulator is bound at that
+ * address, if the device is not a pmbus regulator, or if
+ * CONFIG_DM_REGULATOR_PMBUS_HELPER is disabled.
+ *
+ * Lets pmbus_set_active() -- and thus the pmbus CLI and the board
+ * boot snapshots -- reuse the rich, VOUT_MODE detected driver_info of
+ * a DT bound generic / chip regulator when the device is selected by
+ * raw <bus>:<addr> (which has no chip-match registry entry and would
+ * otherwise fall back to blanket LINEAR16 / LINEAR11 decoding).
+ */
+const struct pmbus_driver_info *pmbus_regulator_info_by_addr(int bus_seq,
+ u8 addr);
+
/*
* Status bit name decoding.
*
diff --git a/lib/pmbus.c b/lib/pmbus.c
index d49576ad3bd..920f7b09a4b 100644
--- a/lib/pmbus.c
+++ b/lib/pmbus.c
@@ -761,6 +761,23 @@ int pmbus_set_active(int bus_seq, u8 addr)
sizeof(pmbus_active_state.vendor));
}
+ /*
+ * No MFR_ID chip-match (a spec compliant part with no per chip
+ * driver, e.g. a Flex / Delta PSU): if a generic / chip
+ * UCLASS_REGULATOR is bound at this address, reuse its
+ * VOUT_MODE detected driver_info so telemetry decodes through
+ * the right per class formats instead of the blanket
+ * LINEAR16 / LINEAR11 fallback.
+ */
+ if (CONFIG_IS_ENABLED(DM_REGULATOR_PMBUS_HELPER) &&
+ !pmbus_active_state.info) {
+ const struct pmbus_driver_info *di =
+ pmbus_regulator_info_by_addr(bus_seq, addr);
+
+ if (di)
+ pmbus_active_state.info = di;
+ }
+
/*
* MFR_MODEL / MFR_REVISION are best effort. Use the same byte
* order the matched chip declared; if nothing matched, use the
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 19:56 ` [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
2026-07-02 20:07 ` [PATCH v2 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
@ 2026-07-02 20:14 ` Vincent Jardin
2026-07-06 3:43 ` Peng Fan
2026-07-02 20:15 ` [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
` (3 subsequent siblings)
6 siblings, 1 reply; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 20:14 UTC (permalink / raw)
To: u-boot; +Cc: sjg, trini
Per-chip UCLASS_REGULATOR driver for the MPS MPQ8785 / MPM3695 /
MPM3695-25 / MPM82504 family, layered on the shared pmbus_helper
adapter. Runs Linux's mpq8785_identify() VOUT_MODE switch
(LINEAR16 vs DIRECT m=64 R=1) at probe time, applies the optional
mps,vout-fb-divider-ratio-permille DT property, and walks the
documented MPS ADDR_VBOOT windows on MFR_ID failure so a
die-revision address shift just works.
Publishes the pmbus mps last|clear last|clear force vendor
extension subcommands (NVM PROTECTION_LAST read and clear) when
CMD_PMBUS is enabled.
Adaapted from Linux code.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
MAINTAINERS | 1 +
drivers/power/regulator/Kconfig | 9 +
drivers/power/regulator/Makefile | 1 +
drivers/power/regulator/mpq8785.c | 494 ++++++++++++++++++++++++++++++
4 files changed, 505 insertions(+)
create mode 100644 drivers/power/regulator/mpq8785.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 123ea9ed3ed..5ba9b195c0b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1585,6 +1585,7 @@ M: Vincent Jardin <vjardin@free.fr>
S: Maintained
F: cmd/pmbus.c
F: doc/develop/pmbus.rst
+F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 5b1a9c3f991..67c9e1fb377 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -581,3 +581,12 @@ config DM_REGULATOR_PMBUS_GENERIC
per chip driver only when chip specific quirks (vendor
registers, VID coercion, ADDR pin auto promotion, non standard
m / b / R coefficients) need handling.
+
+config DM_REGULATOR_MPQ8785
+ bool "MPS MPQ8785 / MPM3695 / MPM82504 PMBus voltage regulator"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Driver for the Monolithic Power Systems MPQ8785 family of
+ digital multiphase voltage regulators with PMBus. Supports
+ MPM3695, MPM3695-25, MPM82504, and MPQ8785. Adapted from the
+ Linux drivers/hwmon/pmbus/mpq8785.c reference.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index b084e9ac4bc..aa3faf2f34f 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -51,3 +51,4 @@ obj-$(CONFIG_DM_REGULATOR_MT6357) += mt6357_regulator.o
obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
+obj-$(CONFIG_DM_REGULATOR_MPQ8785) += mpq8785.o
diff --git a/drivers/power/regulator/mpq8785.c b/drivers/power/regulator/mpq8785.c
new file mode 100644
index 00000000000..dc321f0e410
--- /dev/null
+++ b/drivers/power/regulator/mpq8785.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * MPS MPQ8785 / MPM3695 / MPM3695-25 / MPM82504 PMBus voltage
+ * regulator driver. Adapted from
+ * linux/drivers/hwmon/pmbus/mpq8785.c
+ * (Charles Hsu, GPL-2.0-or-later) with the kernel hwmon publication
+ * and caching layers stripped.
+ *
+ * Hooks the shared pmbus_helper UCLASS_REGULATOR ops + adds the MPS
+ * specific identify (VOUT_MODE switch between LINEAR16 and DIRECT
+ * m=64 R=1 for the chip's "VID" mode), the MPS vendor extension
+ * (pmbus mps last|clear last|clear force), and ADDR_VBOOT auto
+ * promotion when the DT declared address fails the MFR_ID probe.
+ */
+
+#include <command.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <vsprintf.h>
+#include <linux/bitops.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+/* Chip family identifiers (driver_data). */
+enum mpq_chip_id {
+ MPQ_MPM3695 = 0,
+ MPQ_MPM3695_25 = 1,
+ MPQ_MPM82504 = 2,
+ MPQ_MPQ8785 = 3,
+};
+
+/*
+ * MPS vendor extended command codes (NOT in PMBus 1.3 Part II).
+ *
+ * CLEAR_LAST_FAULT (08h) clears the NVM backed PROTECTION_LAST
+ * register. Gated by MFR_CFG_EXT (F5h)
+ * bit[6] = 1; chip silently no ops if the
+ * gate is cleared.
+ * PROTECTION_LAST (FBh) single event, NVM backed log of the last
+ * protection event. Survives the chip's own
+ * power cycle. The boot time post mortem the
+ * SoC has no other way to obtain.
+ *
+ * NEVER issue CLEAR_LAST_FAULT (08h) implicitly; it would erase the
+ * post mortem trail. Only the explicit pmbus mps clear last and
+ * pmbus mps clear force subcommands write it.
+ */
+#define PMBUS_CLEAR_LAST_FAULT 0x08
+#define MPS_PROTECTION_LAST 0xfb
+
+/*
+ * MFR_CFG_EXT (F5h) is an MPS extended config WORD (16 bits, not a
+ * byte). Bit[6] (MFR_CLR_FAULT_CFG) gates CLEAR_LAST_FAULT (08h)
+ * clearing PROTECTION_LAST. Several other bits are fixed and MUST be
+ * preserved on writeback; always read modify write the full 16 bits,
+ * only flip bit[6], restore on the way out.
+ */
+#define MPS_MFR_CFG_EXT 0xf5
+#define MPS_MFR_CFG_EXT_CLR_LAST_EN BIT(6)
+
+/*
+ * MPQ8785 driver_info (transcribed from Linux's
+ * drivers/hwmon/pmbus/mpq8785.c::mpq8785_info). DIRECT format with
+ * chip specific m / b / R coefficients on VIN, IOUT, TEMPERATURE.
+ * VOUT format is selected at probe time from VOUT_MODE: bits[7:5] == 0
+ * selects LINEAR16, bits[7:5] == 1 or 2 selects DIRECT m=64 R=1.
+ */
+
+/*
+ * MPS-extended STATUS_* bit names. The MPQ8785 family reuses several
+ * bit positions documented as RESERVED / UNKNOWN / NONE_ABOVE /
+ * MFR_SPECIFIC by PMBus 1.3 for chip specific signals. The override
+ * table below substitutes the chip name for the standard one when
+ * the bit is set, leaving every other PMBus 1.3 standard bit
+ * (VOUT_OV, IOUT_OC, TEMP, CML, ...) unchanged.
+ *
+ * STATUS_WORD bit[12] spec MFR_SPECIFIC chip NVM_SUMMARY (NVM
+ * backed PROTECTION_LAST
+ * register is non zero)
+ * STATUS_WORD bit[8] spec UNKNOWN chip WATCH_DOG (internal
+ * calculation FSM watchdog
+ * overflow)
+ * STATUS_WORD bit[0] spec NONE_ABOVE chip DRMOS_FAULT (DrMOS
+ * stage fault)
+ * STATUS_CML bit[4] spec MEMORY chip MTP_CRC_FAULT (NVM
+ * CRC mismatch on restore)
+ * STATUS_CML bit[0] spec OTHER_MEM_LOGIC chip MTP_FAULT (NVM
+ * signature fault)
+ * STATUS_TEMPERATURE bit[0] (PMBus leaves bits[3:0] reserved on
+ * this register) chip
+ * OT_SELF (controller die
+ * OT condition)
+ */
+static const struct pmbus_status_override mpq8785_status_overrides[] = {
+ { PMBUS_STATUS_WORD, BIT(12), "NVM_SUMMARY" },
+ { PMBUS_STATUS_WORD, BIT(8), "WATCH_DOG" },
+ { PMBUS_STATUS_WORD, BIT(0), "DRMOS_FAULT" },
+ { PMBUS_STATUS_CML, BIT(4), "MTP_CRC_FAULT" },
+ { PMBUS_STATUS_CML, BIT(0), "MTP_FAULT" },
+ { PMBUS_STATUS_TEMPERATURE, BIT(0), "OT_SELF" },
+ { /* sentinel */ }
+};
+
+static struct pmbus_driver_info mpq8785_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_direct,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_linear, /* refined per VOUT_MODE */
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_direct,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_IN] = 4, .b[PSC_VOLTAGE_IN] = 0, .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_CURRENT_OUT] = 16, .b[PSC_CURRENT_OUT] = 0, .R[PSC_CURRENT_OUT] = 0,
+ .m[PSC_TEMPERATURE] = 1, .b[PSC_TEMPERATURE] = 0, .R[PSC_TEMPERATURE] = 0,
+ /*
+ * Sensor set this family actually implements with calibrated
+ * coefficients: VIN, VOUT, IOUT, TEMP. READ_IIN / READ_POUT are
+ * ACKed by the silicon but uncalibrated here (the kernel's mpq8646
+ * / mpq8785 drivers expose neither), so declaring the set keeps
+ * pmbus_print_telemetry from printing a bogus POUT / IIN -- matching
+ * the kernel's per-chip sensor list.
+ */
+ .classes_present = BIT(PSC_VOLTAGE_IN) | BIT(PSC_VOLTAGE_OUT) |
+ BIT(PSC_CURRENT_OUT) | BIT(PSC_TEMPERATURE),
+ .status_overrides = mpq8785_status_overrides,
+};
+
+/*
+ * MPM3695 / MPM3695-25 / MPM82504 driver_info: VOUT in DIRECT format
+ * with chip family default m=8 R=2. Other sensor classes default to
+ * LINEAR (the chip family does not document non standard formats for
+ * VIN / IOUT / TEMPERATURE; the helper falls back to LINEAR11 when
+ * the active info is non NULL but format[c] is linear).
+ */
+static struct pmbus_driver_info mpm82504_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct,
+ .m[PSC_VOLTAGE_OUT] = 8, .b[PSC_VOLTAGE_OUT] = 0, .R[PSC_VOLTAGE_OUT] = 2,
+ .format[PSC_VOLTAGE_IN] = pmbus_fmt_linear,
+ .format[PSC_CURRENT_OUT] = pmbus_fmt_linear,
+ .format[PSC_TEMPERATURE] = pmbus_fmt_linear,
+};
+
+/*
+ * Chip match for the framework's pmbus dev <bus>:<addr> raw I2C
+ * path. Used when the operator selects the chip directly by address
+ * instead of by regulator-name; the framework probes MFR_ID, sees
+ * "MPS" (after the byte reverse helper), and caches mpq8785_info.
+ */
+static const struct pmbus_chip_match mpq8785_match = {
+ .mfr_id = "MPS",
+ .mfr_id_reverse = true,
+ .vendor = "mps",
+ .info = &mpq8785_info,
+};
+
+static const struct pmbus_bit mpq_protection_last_bits[] = {
+ { 1u << 15, "INIT_FAULT" },
+ { 1u << 14, "NVM_CRC_ERROR" },
+ { 1u << 13, "NVM_FAULT" },
+ { 1u << 12, "OC_PHASE_FAULT" },
+ { 1u << 11, "OTP_SELF_FAULT" },
+ { 1u << 9, "SWITCH_PRD_FAULT" },
+ { 1u << 8, "VIN_OV_FAULT" },
+ { 1u << 7, "VOUT_OV_FAULT" },
+ { 1u << 6, "VOUT_UV_FAULT" },
+ { 1u << 5, "OC_TOT_FAULT" },
+ { 1u << 4, "VIN_UVLO_FAULT" },
+ { 1u << 3, "DRMOS_OTP" },
+ { /* sentinel */ }
+};
+
+static int mps_require_active(struct udevice **chip)
+{
+ const struct pmbus_active_dev *act = pmbus_active();
+
+ if (!act) {
+ printf("pmbus mps: no active device. Use 'pmbus dev <bus>:<addr>' first.\n");
+ return CMD_RET_FAILURE;
+ }
+ if (strcmp(act->vendor, "mps") != 0) {
+ printf("pmbus mps: active device is not from vendor 'mps' (got '%s')\n",
+ act->vendor[0] ? act->vendor : "(generic)");
+ return CMD_RET_FAILURE;
+ }
+ if (pmbus_active_get_i2c(chip)) {
+ printf("pmbus mps: cannot reach i2c%d:0x%02x\n",
+ act->bus_seq, act->addr);
+ return CMD_RET_FAILURE;
+ }
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_last(struct udevice *chip)
+{
+ u16 prot_last = 0;
+
+ if (pmbus_read_word(chip, MPS_PROTECTION_LAST, &prot_last)) {
+ printf("pmbus mps: PROTECTION_LAST (FBh) read failed\n");
+ return CMD_RET_FAILURE;
+ }
+ printf("PROTECTION_LAST (FBh) = 0x%04x [", prot_last);
+ pmbus_print_bits(prot_last, mpq_protection_last_bits);
+ printf("] (NVM, survives MPQ power cycle)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_clear_last(struct udevice *chip)
+{
+ int ret;
+
+ printf("pmbus mps: WARNING, erasing NVM PROTECTION_LAST (FBh) post mortem\n");
+ ret = dm_i2c_write(chip, PMBUS_CLEAR_LAST_FAULT, NULL, 0);
+ if (ret) {
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) write failed (%d)\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) issued; gated by MFR_CFG_EXT bit[6]\n");
+ printf(" (chip silently no ops if F5h bit[6] = 0; verify by re reading FBh)\n");
+ return CMD_RET_SUCCESS;
+}
+
+static int mps_do_clear_force(struct udevice *chip)
+{
+ u8 wp_orig = 0;
+ u16 cfg_orig = 0, cfg_unlocked;
+ int ret, last_rc = 0, rc;
+
+ printf("pmbus mps: FORCE; temporarily lowering WRITE_PROTECT and MFR_CFG_EXT.CLEAR_LAST_EN\n");
+ printf("pmbus mps: WARNING, erasing NVM PROTECTION_LAST (FBh) post mortem\n");
+
+ ret = pmbus_read_byte(chip, PMBUS_WRITE_PROTECT, &wp_orig);
+ if (ret) {
+ printf("pmbus mps: WRITE_PROTECT (10h) read failed (%d), aborting force\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ ret = pmbus_read_word(chip, MPS_MFR_CFG_EXT, &cfg_orig);
+ if (ret) {
+ printf("pmbus mps: MFR_CFG_EXT (F5h) read failed (%d), aborting force\n", ret);
+ return CMD_RET_FAILURE;
+ }
+ printf("pmbus mps: saved WRITE_PROTECT=0x%02x MFR_CFG_EXT=0x%04x\n",
+ wp_orig, cfg_orig);
+
+ if (wp_orig != 0) {
+ u8 wp_open = 0x00;
+
+ ret = dm_i2c_write(chip, PMBUS_WRITE_PROTECT, &wp_open, 1);
+ if (ret) {
+ printf("pmbus mps: WRITE_PROTECT clear failed (%d), chip refuses unlock\n",
+ ret);
+ return CMD_RET_FAILURE;
+ }
+ }
+
+ cfg_unlocked = cfg_orig | MPS_MFR_CFG_EXT_CLR_LAST_EN;
+ ret = pmbus_write_word(chip, MPS_MFR_CFG_EXT, cfg_unlocked);
+ if (ret) {
+ printf("pmbus mps: MFR_CFG_EXT <- 0x%04x failed (%d)\n",
+ cfg_unlocked, ret);
+ goto restore_wp;
+ }
+
+ last_rc = dm_i2c_write(chip, PMBUS_CLEAR_LAST_FAULT, NULL, 0);
+ if (last_rc)
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) write failed (%d) even with gate open\n",
+ last_rc);
+ else
+ printf("pmbus mps: CLEAR_LAST_FAULT (08h) issued with MFR_CFG_EXT bit[6]=1, PROTECTION_LAST should now read 0x0000\n");
+
+ rc = pmbus_write_word(chip, MPS_MFR_CFG_EXT, cfg_orig);
+ if (rc)
+ printf("pmbus mps: MFR_CFG_EXT restore failed (%d), gate may stay open until POR\n",
+ rc);
+
+restore_wp:
+ if (wp_orig != 0) {
+ rc = dm_i2c_write(chip, PMBUS_WRITE_PROTECT, &wp_orig, 1);
+ if (rc)
+ printf("pmbus mps: WRITE_PROTECT restore failed (%d), chip stays unlocked until POR\n",
+ rc);
+ }
+
+ return (ret || last_rc) ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int mps_vendor_handler(struct cmd_tbl *cmdtp, int flag, int argc,
+ char *const argv[])
+{
+ struct udevice *chip;
+ int rc;
+
+ if (argc < 2)
+ return CMD_RET_USAGE;
+
+ rc = mps_require_active(&chip);
+ if (rc)
+ return rc;
+
+ if (!strcmp(argv[1], "last") && argc == 2)
+ return mps_do_last(chip);
+ if (!strcmp(argv[1], "clear") && argc >= 3) {
+ if (!strcmp(argv[2], "last"))
+ return mps_do_clear_last(chip);
+ if (!strcmp(argv[2], "force"))
+ return mps_do_clear_force(chip);
+ }
+ return CMD_RET_USAGE;
+}
+
+static const struct pmbus_vendor_op mps_vendor_op = {
+ .vendor = "mps",
+ .handler = mps_vendor_handler,
+ .help = "pmbus mps last : read MPS PROTECTION_LAST (FBh)\n"
+ "pmbus mps clear last : issue MPS CLEAR_LAST_FAULT (08h) (DESTRUCTIVE)\n"
+ "pmbus mps clear force : force clear via MFR_CFG_EXT bit[6] (DESTRUCTIVE)\n",
+};
+
+static void mpq8785_identify_vout(struct udevice *i2c_dev)
+{
+ enum pmbus_data_format fmt;
+
+ /*
+ * Let the shared helper read VOUT_MODE and pick the base format
+ * (the single source of truth for the bit layout). The MPS quirk:
+ * this family encodes VOUT in DIRECT with m=64 R=1 whenever
+ * VOUT_MODE reports VID *or* DIRECT -- override the helper's
+ * generic DIRECT m=1 / VID-unwired result in those two modes.
+ * LINEAR and IEEE754 keep the helper's selection unchanged.
+ */
+ fmt = pmbus_regulator_identify_vout(i2c_dev, &mpq8785_info);
+ if (fmt == pmbus_fmt_vid || fmt == pmbus_fmt_direct) {
+ mpq8785_info.format[PSC_VOLTAGE_OUT] = pmbus_fmt_direct;
+ mpq8785_info.m[PSC_VOLTAGE_OUT] = 64;
+ mpq8785_info.b[PSC_VOLTAGE_OUT] = 0;
+ mpq8785_info.R[PSC_VOLTAGE_OUT] = 1;
+ }
+}
+
+/*
+ * The MPQ8785 datasheet revision letter changes which window the
+ * analog ADDR_VBOOT level resolves to. Boards have been observed at
+ * 0x10 (later die rev) versus the 0x20 the original driver assumed.
+ * If the DT declared address fails the MFR_ID probe at probe time,
+ * walk the three documented windows looking for an MPS responder.
+ *
+ * Each window covers 16 consecutive 7 bit I2C addresses; the low
+ * nibble selects the chip's MFR_ADDR_PMBUS slot within the window.
+ */
+#define MPS_ADDR_VBOOT_WINDOW_SIZE 16
+static const u8 mps_addr_window_starts[] = { 0x10, 0x20, 0x60 };
+
+static int mpq8785_probe_addr(struct udevice *bus, u8 addr,
+ struct udevice **chip_out)
+{
+ char id[PMBUS_MFR_STRING_MAX] = "";
+ struct udevice *chip;
+ int ret;
+
+ ret = i2c_get_chip(bus, addr, 1, &chip);
+ if (ret)
+ return ret;
+ ret = pmbus_read_string(chip, PMBUS_MFR_ID, id, sizeof(id), true);
+ if (ret < 0)
+ return ret;
+ if (strncmp(id, "MPS", 3) != 0)
+ return -ENODEV;
+ *chip_out = chip;
+ return 0;
+}
+
+static int mpq8785_scan_windows(struct udevice *bus, u8 *found_addr,
+ struct udevice **chip_out)
+{
+ unsigned int i, j;
+
+ for (i = 0; i < ARRAY_SIZE(mps_addr_window_starts); i++) {
+ for (j = 0; j < MPS_ADDR_VBOOT_WINDOW_SIZE; j++) {
+ u8 addr = mps_addr_window_starts[i] + j;
+
+ if (mpq8785_probe_addr(bus, addr, chip_out) == 0) {
+ *found_addr = addr;
+ return 0;
+ }
+ }
+ }
+ return -ENODEV;
+}
+
+static struct pmbus_driver_info *mpq8785_pick_info(enum mpq_chip_id chip_id)
+{
+ switch (chip_id) {
+ case MPQ_MPM3695:
+ case MPQ_MPM3695_25:
+ case MPQ_MPM82504:
+ return &mpm82504_info;
+ case MPQ_MPQ8785:
+ default:
+ return &mpq8785_info;
+ }
+}
+
+static int mpq8785_probe(struct udevice *dev)
+{
+ enum mpq_chip_id chip_id = (enum mpq_chip_id)dev_get_driver_data(dev);
+ struct pmbus_regulator_priv *priv = dev_get_priv(dev);
+ struct pmbus_driver_info *info = mpq8785_pick_info(chip_id);
+ static bool match_registered;
+ static bool vendor_registered;
+ u32 fb_div;
+ int ret;
+
+ ret = pmbus_regulator_probe_common(dev, info, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * Verify the chip answers MFR_ID="MPS" at the DT declared
+ * address. If it doesn't, walk the documented ADDR_VBOOT windows
+ * looking for it (a die rev address shift). On a hit, replace
+ * priv->i2c_dev with the discovered chip handle and continue.
+ */
+ {
+ char id[PMBUS_MFR_STRING_MAX] = "";
+
+ ret = pmbus_read_string(priv->i2c_dev, PMBUS_MFR_ID, id,
+ sizeof(id), true);
+ if (ret < 0 || strncmp(id, "MPS", 3) != 0) {
+ struct udevice *bus = dev_get_parent(dev);
+ struct udevice *promoted;
+ u8 found = 0;
+
+ if (mpq8785_scan_windows(bus, &found, &promoted) == 0) {
+ printf("MPQ8785: DT addr 0x%02x silent, auto promoted to 0x%02x\n",
+ (unsigned int)dev_read_addr(dev), found);
+ priv->i2c_dev = promoted;
+ } else {
+ printf("MPQ8785: no MPS responder found in 0x10..0x1f / 0x20..0x2f / 0x60..0x6f\n");
+ return -ENODEV;
+ }
+ }
+ }
+
+ /* MPQ8785 specific: refine VOUT format from VOUT_MODE. */
+ if (chip_id == MPQ_MPQ8785)
+ mpq8785_identify_vout(priv->i2c_dev);
+
+ /* Apply mps,vout-fb-divider-ratio-permille if present in DT. */
+ fb_div = dev_read_u32_default(dev, "mps,vout-fb-divider-ratio-permille", 0);
+ if (fb_div) {
+ ret = pmbus_regulator_apply_voltage_scale(dev, fb_div);
+ if (ret) {
+ printf("MPQ8785: VOUT_SCALE_LOOP write failed (%d)\n", ret);
+ return ret;
+ }
+ }
+
+ /*
+ * Register the chip match and the MPS vendor handler exactly
+ * once across all bound MPS regulators (a board could legally
+ * carry several). Both registries are global and idempotent
+ * matches return -ENOSPC, so the static guards keep things
+ * tidy.
+ */
+ if (!match_registered) {
+ if (pmbus_register_chip(&mpq8785_match) == 0)
+ match_registered = true;
+ }
+ if (!vendor_registered) {
+ if (pmbus_register_vendor_handler(&mps_vendor_op) == 0)
+ vendor_registered = true;
+ }
+ return 0;
+}
+
+static const struct udevice_id mpq8785_ids[] = {
+ { .compatible = "mps,mpm3695", .data = MPQ_MPM3695 },
+ { .compatible = "mps,mpm3695-25", .data = MPQ_MPM3695_25 },
+ { .compatible = "mps,mpm82504", .data = MPQ_MPM82504 },
+ { .compatible = "mps,mpq8785", .data = MPQ_MPQ8785 },
+ { }
+};
+
+U_BOOT_DRIVER(mpq8785_regulator) = {
+ .name = "mpq8785_regulator",
+ .id = UCLASS_REGULATOR,
+ .of_match = mpq8785_ids,
+ .probe = mpq8785_probe,
+ .ops = &pmbus_regulator_ops,
+ .priv_auto = sizeof(struct pmbus_regulator_priv),
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (2 preceding siblings ...)
2026-07-02 20:14 ` [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
@ 2026-07-02 20:15 ` Vincent Jardin
2026-07-06 3:41 ` Peng Fan
2026-07-02 22:26 ` [PATCH v2 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
` (2 subsequent siblings)
6 siblings, 1 reply; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 20:15 UTC (permalink / raw)
To: u-boot; +Cc: sjg, trini
Wire board/nxp/common/vid.c into the <pmbus.h> framework so the legacy
NXP AVS path stops carrying its own duplicate copy of the PMBus
protocol and instead consumes the shared constants, decoders, and
transport helpers.
vid.c is the legacy NXP AVS/pre-kernel voltage-trim path for lx2160 CPUs.
It does PMBus to whichever core-rail voltage monitor the board carries:
LTC3882 or ISL68233 are selected with
CONFIG_VOL_MONITOR_LTC3882_*/CONFIG_VOL_MONITOR_ISL68233_*.
Before this change the file kept its own local PMBUS_CMD_* command-code
defines, its own inline LINEAR16 mantissa/exponent math, and called
into I2C through the I2C_READ/I2C_WRITE NXP wrappers in
board/nxp/common/i2c_common.{c,h} which is a parallel implementation of
exactly what <pmbus.h> + lib/pmbus.c provides.
The intent is to make vid.c an consumer of the new PMBus.
Compatibility with the former support:
- CLI unchanged: vdd_override and vdd_read keep their existing
semantics, return codes, and diagnostic output.
- I2C transport unchanged on the wire: the framework's pmbus_*
helpers call dm_i2c_read/dm_i2c_write: the same DM I2C
backing that vid.c's former I2C_READ/I2C_WRITE macros already
routed through on DM_I2C.
- Numeric decode is bit-equivalent: pmbus_reg2data_linear16() and
pmbus_data2reg_linear16() implement the PMBus 1.3 Part II
mantissa/exponent.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
arch/Kconfig.nxp | 4 ++
board/nxp/common/vid.c | 104 ++++++++++++++++++++++-------------------
board/nxp/common/vid.h | 15 +++---
3 files changed, 68 insertions(+), 55 deletions(-)
diff --git a/arch/Kconfig.nxp b/arch/Kconfig.nxp
index ef9087d0197..152692e3230 100644
--- a/arch/Kconfig.nxp
+++ b/arch/Kconfig.nxp
@@ -242,24 +242,28 @@ config VOL_MONITOR_IR36021_SET
config VOL_MONITOR_LTC3882_READ
bool "Enable the LTC3882 voltage monitor read"
+ select PMBUS
help
This option enables LTC3882 voltage monitor read
functionality. It is used by the common VID driver.
config VOL_MONITOR_LTC3882_SET
bool "Enable the LTC3882 voltage monitor set"
+ select PMBUS
help
This option enables LTC3882 voltage monitor set
functionality. It is used by the common VID driver.
config VOL_MONITOR_ISL68233_READ
bool "Enable the ISL68233 voltage monitor read"
+ select PMBUS
help
This option enables ISL68233 voltage monitor read
functionality. It is used by the common VID driver.
config VOL_MONITOR_ISL68233_SET
bool "Enable the ISL68233 voltage monitor set"
+ select PMBUS
help
This option enables ISL68233 voltage monitor set
functionality. It is used by the common VID driver.
diff --git a/board/nxp/common/vid.c b/board/nxp/common/vid.c
index 84cb43fad56..a91d6c9381a 100644
--- a/board/nxp/common/vid.c
+++ b/board/nxp/common/vid.c
@@ -11,6 +11,7 @@
#include <i2c.h>
#include <irq_func.h>
#include <log.h>
+#include <pmbus.h>
#include <vsprintf.h>
#include <asm/io.h>
#ifdef CONFIG_FSL_LSCH2
@@ -260,45 +261,38 @@ static int read_voltage_from_IR(int i2caddress)
*/
#define VOUT_WARNING "VID: VOUT_MODE exponent has resolution worse than 1 V!\n"
-/* Checks the PMBus voltage monitor for the format used for voltage values */
-static int get_pmbus_multiplier(DEVICE_HANDLE_T dev)
+/*
+ * Read VOUT_MODE for downstream LINEAR16 decode/encode through the
+ * tree level <pmbus.h> helpers (pmbus_reg2data_linear16,
+ * pmbus_data2reg_linear16). Returns the raw VOUT_MODE byte on
+ * success, or 0 on bus error. Emits VOUT_WARNING on Linear mode
+ * chips with a non negative exponent (resolution >= 1 V is unusable
+ * for sub volt SoC rails) and an informational note on the
+ * unsupported VID format.
+ */
+static u8 vid_read_vout_mode(DEVICE_HANDLE_T dev)
{
- u8 mode;
- int exponent, multiplier, ret;
+ u8 mode = 0;
+ int ret;
- ret = I2C_READ(dev, PMBUS_CMD_VOUT_MODE, &mode, sizeof(mode));
+ ret = pmbus_read_byte(dev, PMBUS_VOUT_MODE, &mode);
if (ret) {
printf("VID: unable to determine voltage multiplier\n");
- return 1;
+ return 0;
}
- /* Upper 3 bits is mode, lower 5 bits is exponent */
- exponent = (int)mode & 0x1F;
- mode >>= 5;
- switch (mode) {
- case 0:
- /* Linear, 5 bit twos component exponent */
- if (exponent & 0x10) {
- multiplier = 1 << (16 - (exponent & 0xF));
- } else {
- /* If exponent is >= 0, then resolution is 1 V! */
+ switch (mode & PB_VOUT_MODE_MODE_MASK) {
+ case PB_VOUT_MODE_LINEAR:
+ if (!(mode & 0x10))
printf(VOUT_WARNING);
- multiplier = 1;
- }
break;
- case 1:
- /* VID code identifier */
+ case PB_VOUT_MODE_VID:
printf("VID: custom VID codes are not supported\n");
- multiplier = MV_PER_V;
break;
default:
- /* Direct, in mV */
- multiplier = MV_PER_V;
break;
}
-
- debug("VID: calculated multiplier is %d\n", multiplier);
- return multiplier;
+ return mode;
}
#endif
@@ -306,8 +300,8 @@ static int get_pmbus_multiplier(DEVICE_HANDLE_T dev)
defined(CONFIG_VOL_MONITOR_LTC3882_READ)
static int read_voltage_from_pmbus(int i2caddress)
{
- int ret, multiplier, vout;
- u8 channel = PWM_CHANNEL0;
+ int ret, vout;
+ u8 channel = PWM_CHANNEL0, vout_mode;
u16 vcode;
DEVICE_HANDLE_T dev;
@@ -317,25 +311,31 @@ static int read_voltage_from_pmbus(int i2caddress)
return ret;
/* Select the right page */
- ret = I2C_WRITE(dev, PMBUS_CMD_PAGE, &channel, sizeof(channel));
+ ret = pmbus_write_byte(dev, PMBUS_PAGE, channel);
if (ret) {
printf("VID: failed to select VDD page %d\n", channel);
return ret;
}
- /* VOUT is little endian */
- ret = I2C_READ(dev, PMBUS_CMD_READ_VOUT, (void *)&vcode, sizeof(vcode));
+ ret = pmbus_read_word(dev, PMBUS_READ_VOUT, &vcode);
if (ret) {
printf("VID: failed to read core voltage\n");
return ret;
}
- /* Scale down to the real mV */
- multiplier = get_pmbus_multiplier(dev);
- vout = (int)vcode;
- /* Multiplier 1000 (direct mode) requires no change to convert */
- if (multiplier != MV_PER_V)
- vout = DIV_ROUND_UP(vout * MV_PER_V, multiplier);
+ /*
+ * Decode LINEAR16 via the tree level helper from <pmbus.h>. For
+ * non Linear VOUT_MODE settings the helper returns 0; fall back
+ * to the historic mV pass through so existing LSCH boards keep.
+ */
+ vout_mode = vid_read_vout_mode(dev);
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) == PB_VOUT_MODE_LINEAR) {
+ s64 uv = pmbus_reg2data_linear16(vcode, vout_mode);
+
+ vout = (int)((uv + 500) / 1000); /* round to mV */
+ } else {
+ vout = (int)vcode;
+ }
return vout - board_vdd_drop_compensation();
}
#endif
@@ -463,11 +463,13 @@ static int set_voltage_to_IR(int i2caddress, int vdd)
static int set_voltage_to_pmbus(int i2caddress, int vdd)
{
int ret, vdd_last, vdd_target = vdd;
- int count = MAX_LOOP_WAIT_NEW_VOL, temp = 0, multiplier;
+ int count = MAX_LOOP_WAIT_NEW_VOL, temp = 0;
+ u8 vout_mode;
+ u16 raw;
unsigned char value;
/* The data to be sent with the PMBus command PAGE_PLUS_WRITE */
- u8 buffer[5] = { 0x04, PWM_CHANNEL0, PMBUS_CMD_VOUT_COMMAND, 0, 0 };
+ u8 buffer[5] = { 0x04, PWM_CHANNEL0, PMBUS_VOUT_COMMAND, 0, 0 };
DEVICE_HANDLE_T dev;
/* Open device handle */
@@ -475,24 +477,28 @@ static int set_voltage_to_pmbus(int i2caddress, int vdd)
if (ret)
return ret;
- /* Scale up to the proper value for the VOUT command, little endian */
- multiplier = get_pmbus_multiplier(dev);
+ /*
+ * Encode target mV as LINEAR16 raw via the tree level helper
+ * from <pmbus.h>. For non Linear VOUT_MODE settings the helper
+ * returns 0; fall back to the historic mV pass through.
+ */
vdd += board_vdd_drop_compensation();
- if (multiplier != MV_PER_V)
- vdd = DIV_ROUND_UP(vdd * multiplier, MV_PER_V);
- buffer[3] = vdd & 0xFF;
- buffer[4] = (vdd & 0xFF00) >> 8;
+ vout_mode = vid_read_vout_mode(dev);
+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) == PB_VOUT_MODE_LINEAR)
+ raw = pmbus_data2reg_linear16((s64)vdd * 1000LL, vout_mode);
+ else
+ raw = (u16)vdd;
+ buffer[3] = raw & 0xFF;
+ buffer[4] = (raw & 0xFF00) >> 8;
/* Check write protect state */
- ret = I2C_READ(dev, PMBUS_CMD_WRITE_PROTECT, (void *)&value,
- sizeof(value));
+ ret = pmbus_read_byte(dev, PMBUS_WRITE_PROTECT, &value);
if (ret)
goto exit;
if (value != EN_WRITE_ALL_CMD) {
value = EN_WRITE_ALL_CMD;
- ret = I2C_WRITE(dev, PMBUS_CMD_WRITE_PROTECT,
- (void *)&value, sizeof(value));
+ ret = pmbus_write_byte(dev, PMBUS_WRITE_PROTECT, value);
if (ret)
goto exit;
}
diff --git a/board/nxp/common/vid.h b/board/nxp/common/vid.h
index b34c080b4ba..72c1c089aa1 100644
--- a/board/nxp/common/vid.h
+++ b/board/nxp/common/vid.h
@@ -22,8 +22,9 @@
#define IR_VDD_STEP_UP 5
/* LTC3882 */
-#define PMBUS_CMD_WRITE_PROTECT 0x10
/*
+ * PMBUS_WRITE_PROTECT (10h) provided by <pmbus.h>
+ *
* WRITE_PROTECT command supported values
* 0x80: Disable all writes except WRITE_PROTECT, PAGE,
* STORE_USER_ALL and MFR_EE_UNLOCK commands.
@@ -51,12 +52,14 @@
#define VDD_MV_MAX 925
#endif
-/* PM Bus commands code for LTC3882*/
+/*
+ * PM Bus commands code for LTC3882. PMBUS_PAGE / PMBUS_READ_VOUT /
+ * PMBUS_VOUT_MODE / PMBUS_VOUT_COMMAND are provided by <pmbus.h>.
+ * PMBUS_CMD_PAGE_PLUS_WRITE (05h) is the LTC3882 SMBus block write
+ * transaction not in <pmbus.h>'s standard subset, so keep its
+ * definition here.
+ */
#define PWM_CHANNEL0 0x0
-#define PMBUS_CMD_PAGE 0x0
-#define PMBUS_CMD_READ_VOUT 0x8B
-#define PMBUS_CMD_VOUT_MODE 0x20
-#define PMBUS_CMD_VOUT_COMMAND 0x21
#define PMBUS_CMD_PAGE_PLUS_WRITE 0x05
#if defined(CONFIG_TARGET_LX2160AQDS) || defined(CONFIG_TARGET_LX2162AQDS) || \
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 5/7] thermal: pmbus: add PMBus die-temp driver
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (3 preceding siblings ...)
2026-07-02 20:15 ` [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
@ 2026-07-02 22:26 ` Vincent Jardin
2026-07-02 22:56 ` [PATCH v2 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
2026-07-02 22:57 ` [PATCH v2 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
6 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 22:26 UTC (permalink / raw)
To: u-boot; +Cc: sjg, trini
The driver is a thin UCLASS_THERMAL: its get_temp reads the
temperature of its parent regulator through the pmbus helper
(READ_TEMPERATURE_1), without any chip-specific code.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
MAINTAINERS | 1 +
drivers/thermal/Kconfig | 8 ++++++++
drivers/thermal/Makefile | 1 +
drivers/thermal/pmbus_thermal.c | 33 +++++++++++++++++++++++++++++++++
4 files changed, 43 insertions(+)
create mode 100644 drivers/thermal/pmbus_thermal.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 5ba9b195c0b..9efc137eb1d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1589,6 +1589,7 @@ F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
+F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 91c39aa4dee..30bb64ce895 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -55,4 +55,12 @@ config TI_LM74_THERMAL
Enable thermal support for the Texas Instruments LM74 chip.
The driver supports reading CPU temperature.
+config PMBUS_THERMAL
+ bool "Generic PMBus temperature"
+ depends on DM_REGULATOR_PMBUS_HELPER
+ help
+ Expose the die-temperature reading of any PMBus voltage
+ regulator bound by a pmbus_helper based chip driver
+ as a UCLASS_THERMAL device.
+
endif # if DM_THERMAL
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index b6f06c00ed9..25435f43b64 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_RCAR_GEN3_THERMAL) += rcar_gen3_thermal.o
obj-$(CONFIG_SANDBOX) += thermal_sandbox.o
obj-$(CONFIG_TI_DRA7_THERMAL) += ti-bandgap.o
obj-$(CONFIG_TI_LM74_THERMAL) += ti-lm74.o
+obj-$(CONFIG_PMBUS_THERMAL) += pmbus_thermal.o
diff --git a/drivers/thermal/pmbus_thermal.c b/drivers/thermal/pmbus_thermal.c
new file mode 100644
index 00000000000..c251cea8ddf
--- /dev/null
+++ b/drivers/thermal/pmbus_thermal.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Generic UCLASS_THERMAL companion for PMBus voltage regulators.
+ *
+ * Works with any chip bound by a pmbus_helper based regulator driver
+ * (drivers/power/regulator/<chip>.c calling
+ * pmbus_regulator_probe_common()). It auto-spawns one
+ * of these thermal devices per regulator.
+ *
+ * The reading is the chip's READ_TEMPERATURE_1 (PMBus 0x8D), decoded
+ * through the parent's pmbus_driver_info.
+ */
+
+#include <dm.h>
+#include <pmbus.h>
+#include <thermal.h>
+
+static int pmbus_thermal_get_temp(struct udevice *dev, int *temp)
+{
+ return pmbus_regulator_read_temp(dev_get_parent(dev), temp);
+}
+
+static const struct dm_thermal_ops pmbus_thermal_ops = {
+ .get_temp = pmbus_thermal_get_temp,
+};
+
+U_BOOT_DRIVER(pmbus_thermal) = {
+ .name = "pmbus_thermal",
+ .id = UCLASS_THERMAL,
+ .ops = &pmbus_thermal_ops,
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (4 preceding siblings ...)
2026-07-02 22:26 ` [PATCH v2 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
@ 2026-07-02 22:56 ` Vincent Jardin
2026-07-02 22:57 ` [PATCH v2 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
6 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 22:56 UTC (permalink / raw)
To: u-boot; +Cc: sjg, trini
Add a UCLASS_I2C_EMUL driver that emulates a PMBus 1.x compliant chip
behind the sandbox I2C bus, plus the test.dts wiring and sandbox
defconfig that bind it to the generic PMBus regulator
(compatible = "pmbus"). This design is a stub only: it lets the
follow-up dm unit test drive lib/pmbus.c, the generic regulator and
the pmbus CLI command with no real hardware.
The emulator models a flat per-command 16-bit register file and the
three identification block strings (MFR_ID / MFR_MODEL /
MFR_REVISION). READ_IIN and READ_POUT are deliberately left
unimplemented (the chip NAKs them) so the telemetry printer's
"(not supported)" path is exercised, mirroring a real buck that only
calibrates a subset of the sensor classes.
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
MAINTAINERS | 1 +
arch/sandbox/dts/test.dts | 10 ++
configs/sandbox_defconfig | 6 +
drivers/power/regulator/Kconfig | 10 ++
drivers/power/regulator/Makefile | 1 +
drivers/power/regulator/sandbox_pmbus.c | 160 ++++++++++++++++++++++++
6 files changed, 188 insertions(+)
create mode 100644 drivers/power/regulator/sandbox_pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 9efc137eb1d..edfa23b7bf9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1589,6 +1589,7 @@ F: drivers/power/regulator/mpq8785.c
F: drivers/power/regulator/pmbus_generic.c
F: drivers/power/regulator/pmbus_helper.c
F: drivers/power/regulator/pmbus_helper.h
+F: drivers/power/regulator/sandbox_pmbus.c
F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 0887de4333b..5032eecceea 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -1027,6 +1027,9 @@
emul1: emull {
compatible = "sandbox,i2c-rtc-emul";
};
+ emul_pmbus: emul-pmbus {
+ compatible = "sandbox,i2c-pmbus";
+ };
};
sandbox_pmic: sandbox_pmic@40 {
@@ -1038,6 +1041,13 @@
reg = <0x41>;
sandbox,emul = <&emul_pmic1>;
};
+
+ pmbus@70 {
+ reg = <0x70>;
+ compatible = "pmbus";
+ regulator-name = "sandbox-pmbus-vout";
+ sandbox,emul = <&emul_pmbus>;
+ };
};
i3c0 {
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index ba800f7d19d..de90a2b39e5 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -392,3 +392,9 @@ CONFIG_UTHREAD=y
CONFIG_UNIT_TEST=y
CONFIG_UT_TIME=y
CONFIG_UT_DM=y
+CONFIG_PMBUS=y
+CONFIG_CMD_PMBUS=y
+CONFIG_DM_REGULATOR_PMBUS_HELPER=y
+CONFIG_DM_REGULATOR_PMBUS_GENERIC=y
+CONFIG_SANDBOX_PMBUS=y
+CONFIG_PMBUS_THERMAL=y
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 67c9e1fb377..143911eeb17 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -590,3 +590,13 @@ config DM_REGULATOR_MPQ8785
digital multiphase voltage regulators with PMBus. Supports
MPM3695, MPM3695-25, MPM82504, and MPQ8785. Adapted from the
Linux drivers/hwmon/pmbus/mpq8785.c reference.
+
+config SANDBOX_PMBUS
+ bool "Sandbox PMBus 1.x chip emulator"
+ depends on SANDBOX && PMBUS && DM_I2C
+ help
+ Emulate a PMBus 1.x compliant chip behind a sandbox I2C bus so
+ the PMBus framework (lib/pmbus.c), the generic regulator
+ (DM_REGULATOR_PMBUS_GENERIC) and the pmbus CLI command can be
+ exercised by the dm unit tests with no real hardware. Only
+ useful for testing; say N on real boards.
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index aa3faf2f34f..b8599ea7fd9 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -52,3 +52,4 @@ obj-$(CONFIG_DM_REGULATOR_MT6359) += mt6359_regulator.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_HELPER) += pmbus_helper.o
obj-$(CONFIG_DM_REGULATOR_PMBUS_GENERIC) += pmbus_generic.o
obj-$(CONFIG_DM_REGULATOR_MPQ8785) += mpq8785.o
+obj-$(CONFIG_SANDBOX_PMBUS) += sandbox_pmbus.o
diff --git a/drivers/power/regulator/sandbox_pmbus.c b/drivers/power/regulator/sandbox_pmbus.c
new file mode 100644
index 00000000000..2900d0a6d83
--- /dev/null
+++ b/drivers/power/regulator/sandbox_pmbus.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Sandbox PMBus 1.x chip stub (UCLASS_I2C_EMUL).
+ *
+ * Stub a DT i2c node so the PMBus framework, the generic pmbus
+ * regulator and the pmbus CLI command can be tested.
+ * The model is a flat per-command 16 bit
+ * register file combined with some fixed identification strings.
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <pmbus.h>
+#include <linux/ctype.h>
+
+#define PMBUS_EMUL_NREG 256
+
+struct sandbox_pmbus_priv {
+ u16 reg[PMBUS_EMUL_NREG];
+ bool supported[PMBUS_EMUL_NREG];
+};
+
+/* Identification strings reported in the natural (forward) byte order. */
+static const char *pmbus_emul_string(u8 cmd)
+{
+ switch (cmd) {
+ case PMBUS_MFR_ID:
+ return "SANDBOX";
+ case PMBUS_MFR_MODEL:
+ return "PMBUS-EMUL";
+ case PMBUS_MFR_REVISION:
+ return "1.0";
+ default:
+ return NULL;
+ }
+}
+
+static int sandbox_pmbus_read(struct sandbox_pmbus_priv *priv, u8 cmd,
+ u8 *buf, int len)
+{
+ const char *str = pmbus_emul_string(cmd);
+ int i;
+
+ if (str) {
+ int slen = strlen(str);
+
+ /* Block payload: [length][bytes...]. */
+ buf[0] = (u8)slen;
+ for (i = 1; i < len; i++)
+ buf[i] = (i - 1 < slen) ? (u8)str[i - 1] : 0;
+ return 0;
+ }
+
+ if (!priv->supported[cmd])
+ return -EREMOTEIO; /* chip NAKs an unimplemented command */
+
+ for (i = 0; i < len; i++)
+ buf[i] = (u8)(priv->reg[cmd] >> (8 * i));
+ return 0;
+}
+
+static int sandbox_pmbus_write(struct sandbox_pmbus_priv *priv, u8 cmd,
+ const u8 *buf, int len)
+{
+ if (len == 0)
+ return 0; /* send-byte (eg CLEAR_FAULTS): just ACK */
+ if (!priv->supported[cmd])
+ return -EREMOTEIO;
+ if (len == 1)
+ priv->reg[cmd] = buf[0];
+ else
+ priv->reg[cmd] = (u16)buf[0] | ((u16)buf[1] << 8);
+ return 0;
+}
+
+static int sandbox_pmbus_xfer(struct udevice *emul, struct i2c_msg *msg,
+ int nmsgs)
+{
+ struct sandbox_pmbus_priv *priv = dev_get_priv(emul);
+ u8 cmd;
+
+ if (nmsgs == 0)
+ return 0;
+ /* A PMBus transaction always opens with the command-code write. */
+ if (msg[0].flags & I2C_M_RD)
+ return -EIO;
+ if (msg[0].len == 0)
+ return 0; /* address-only probe */
+ cmd = msg[0].buf[0];
+
+ if (nmsgs >= 2 && (msg[1].flags & I2C_M_RD))
+ return sandbox_pmbus_read(priv, cmd, msg[1].buf, msg[1].len);
+
+ return sandbox_pmbus_write(priv, cmd, msg[0].buf + 1, msg[0].len - 1);
+}
+
+static void sandbox_pmbus_support(struct sandbox_pmbus_priv *priv, u8 cmd,
+ u16 val)
+{
+ priv->supported[cmd] = true;
+ priv->reg[cmd] = val;
+}
+
+static int sandbox_pmbus_probe(struct udevice *emul)
+{
+ struct sandbox_pmbus_priv *priv = dev_get_priv(emul);
+
+ /* Configuration / identification. */
+ sandbox_pmbus_support(priv, PMBUS_PAGE, 0);
+ sandbox_pmbus_support(priv, PMBUS_OPERATION, PB_OPERATION_ON);
+ sandbox_pmbus_support(priv, PMBUS_ON_OFF_CONFIG, 0);
+ sandbox_pmbus_support(priv, PMBUS_WRITE_PROTECT, 0);
+ sandbox_pmbus_support(priv, PMBUS_CAPABILITY, 0xb0);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_MODE, 0x18); /* LINEAR 2^-8 */
+ sandbox_pmbus_support(priv, PMBUS_VOUT_COMMAND, 0x0200);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_TRIM, 0);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_MAX, 0x0400);
+ sandbox_pmbus_support(priv, PMBUS_VOUT_SCALE_LOOP, 0);
+ sandbox_pmbus_support(priv, PMBUS_REVISION, PMBUS_REV_13);
+
+ /* Status registers, all clean. */
+ sandbox_pmbus_support(priv, PMBUS_STATUS_BYTE, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_WORD, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_VOUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_IOUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_INPUT, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_TEMPERATURE, 0);
+ sandbox_pmbus_support(priv, PMBUS_STATUS_CML, 0);
+
+ /*
+ * Telemetry the emulated chip implements. READ_IIN and READ_POUT
+ * are intentionally absent so callers see the unsupported path.
+ */
+ sandbox_pmbus_support(priv, PMBUS_READ_VIN, 0x0abc);
+ sandbox_pmbus_support(priv, PMBUS_READ_VOUT, 0x0200);
+ sandbox_pmbus_support(priv, PMBUS_READ_IOUT, 0x0123);
+ sandbox_pmbus_support(priv, PMBUS_READ_TEMPERATURE_1, 0x0019);
+
+ return 0;
+}
+
+static struct dm_i2c_ops sandbox_pmbus_emul_ops = {
+ .xfer = sandbox_pmbus_xfer,
+};
+
+static const struct udevice_id sandbox_pmbus_ids[] = {
+ { .compatible = "sandbox,i2c-pmbus" },
+ { }
+};
+
+U_BOOT_DRIVER(sandbox_pmbus_emul) = {
+ .name = "sandbox_pmbus_emul",
+ .id = UCLASS_I2C_EMUL,
+ .of_match = sandbox_pmbus_ids,
+ .probe = sandbox_pmbus_probe,
+ .priv_auto = sizeof(struct sandbox_pmbus_priv),
+ .ops = &sandbox_pmbus_emul_ops,
+};
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* [PATCH v2 7/7] test: dm: pmbus: test pmbus command and framework
2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
` (5 preceding siblings ...)
2026-07-02 22:56 ` [PATCH v2 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
@ 2026-07-02 22:57 ` Vincent Jardin
6 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 22:57 UTC (permalink / raw)
To: u-boot; +Cc: sjg, trini
Add dm unit tests that drive every pmbus subcommand handler against
the sandbox PMBus chip emulator:
dev (select by bus:addr and by regulator-name), list, info,
telemetry, status, dump, read, write, clear, vout, scan and help.
Tested using:
./u-boot -T -c "ut dm pmbus*"
Signed-off-by: Vincent Jardin <vjardin@free.fr>
---
(no changes since v1)
MAINTAINERS | 1 +
test/dm/Makefile | 1 +
test/dm/pmbus.c | 247 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 249 insertions(+)
create mode 100644 test/dm/pmbus.c
diff --git a/MAINTAINERS b/MAINTAINERS
index edfa23b7bf9..410fef2bb1a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1593,6 +1593,7 @@ F: drivers/power/regulator/sandbox_pmbus.c
F: drivers/thermal/pmbus_thermal.c
F: include/pmbus.h
F: lib/pmbus.c
+F: test/dm/pmbus.c
POWER
M: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 0e3c63568dd..76aa1fff9ba 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_PINCONF) += pinmux.o
endif
obj-$(CONFIG_POWER_DOMAIN) += power-domain.o
obj-$(CONFIG_ACPI_PMC) += pmc.o
+obj-$(CONFIG_CMD_PMBUS) += pmbus.o
obj-$(CONFIG_DM_PMIC) += pmic.o
obj-$(CONFIG_DM_PWM) += pwm.o
obj-$(CONFIG_ARM_FFA_TRANSPORT) += ffa.o
diff --git a/test/dm/pmbus.c b/test/dm/pmbus.c
new file mode 100644
index 00000000000..48c8ee11c30
--- /dev/null
+++ b/test/dm/pmbus.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile - Vincent Jardin
+ *
+ * Unit tests for the PMBus 1.x framework, the generic
+ * PMBus regulator and the pmbus CLI command.
+ */
+
+#include <console.h>
+#include <dm.h>
+#include <i2c.h>
+#include <pmbus.h>
+#include <dm/test.h>
+#include <test/test.h>
+#include <test/ut.h>
+
+/* The line pmbus dev prints when a chip is selected */
+#define PMBUS_ACTIVE_LINE \
+ "pmbus: active i2c0:0x70 rail=\"sandbox-pmbus-vout\" " \
+ "MFR_ID=\"SANDBOX\" MODEL=\"PMBUS-EMUL\" vendor=(generic)"
+
+/* The line pmbus list prints for the bound chip */
+#define PMBUS_LIST_LINE \
+ " i2c0:0x70 rail=\"sandbox-pmbus-vout\" node=pmbus@70 " \
+ "driver=pmbus_generic_regulator"
+
+/* Select the emulated chip and check the resulting banner line */
+static int pmbus_select(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus dev 0:0x70", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ return 0;
+}
+
+/* The chip is reachable via UCLASS_REGULATOR (compatible = "pmbus") */
+static int dm_test_pmbus_bind(struct unit_test_state *uts)
+{
+ struct udevice *dev;
+
+ ut_assertok(uclass_get_device_by_name(UCLASS_REGULATOR, "pmbus@70",
+ &dev));
+ ut_asserteq_str("pmbus_generic_regulator", dev->driver->name);
+ ut_asserteq(UCLASS_I2C, device_get_uclass_id(dev_get_parent(dev)));
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_bind, UTF_SCAN_FDT);
+
+/* pmbus dev by <bus>:<addr> and by regulator-name select the chip */
+static int dm_test_pmbus_dev(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus dev 0:0x70", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ /* Selecting by DT regulator-name resolves to the same chip */
+ ut_assertok(run_command("pmbus dev sandbox-pmbus-vout", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ /* pmbus dev with no argument reprints the active chip */
+ ut_assertok(run_command("pmbus dev", 0));
+ ut_assert_nextline(PMBUS_ACTIVE_LINE);
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_dev, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus list enumerates the bound chip among the UCLASS_REGULATOR devices */
+static int dm_test_pmbus_list(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus list", 0));
+ ut_assert_skip_to_line(PMBUS_LIST_LINE);
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_list, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus info decodes identification + the detected driver_info */
+static int dm_test_pmbus_info(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus info", 0));
+ ut_assert_nextline("pmbus device i2c0:0x70");
+ ut_assert_nextline(" regulator-name: \"sandbox-pmbus-vout\"");
+ ut_assert_nextline(" MFR_ID : \"SANDBOX\"");
+ ut_assert_nextline(" MFR_MODEL : \"PMBUS-EMUL\"");
+ ut_assert_nextline(" MFR_REVISION : \"1.0\" raw=0x312e30");
+ ut_assert_nextline(" PMBUS_REVISION: 0x33 (PMBus 1.3)");
+ ut_assert_nextline(" vendor : (none)");
+ ut_assert_nextline(" driver_info : pages=1");
+ ut_assert_nextline(" [VOLTAGE_IN ] format=LINEAR");
+ ut_assert_nextline(" [VOLTAGE_OUT ] format=LINEAR");
+ ut_assert_nextline(" [CURRENT_IN ] format=LINEAR");
+ ut_assert_nextline(" [CURRENT_OUT ] format=LINEAR");
+ ut_assert_nextline(" [POWER ] format=LINEAR");
+ ut_assert_nextline(" [TEMPERATURE ] format=LINEAR");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_info, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/*
+ * pmbus telemetry decodes the implemented sensors and prints
+ * "(not supported)" for the commands the emulator NAKs (READ_IIN,
+ * READ_POUT). LINEAR11 is used for VIN/IOUT/TEMP, LINEAR16 (with the
+ * VOUT_MODE 2^-8 exponent) for VOUT.
+ */
+static int dm_test_pmbus_telemetry(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus telemetry", 0));
+ ut_assert_nextline("pmbus telemetry @ i2c0:0x70");
+ ut_assert_nextline(" VIN : raw=0x0abc 1400.000V");
+ ut_assert_nextline(" VOUT : raw=0x0200 2.000V");
+ ut_assert_nextline(" IIN : (not supported)");
+ ut_assert_nextline(" IOUT : raw=0x0123 291.000A");
+ ut_assert_nextline(" POUT : (not supported)");
+ ut_assert_nextline(" TEMP : raw=0x0019 25.000C");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_telemetry, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus status decodes every STATUS_* register; the emulator is clean */
+static int dm_test_pmbus_status(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus status", 0));
+ ut_assert_nextline("pmbus status @ i2c0:0x70");
+ ut_assert_nextline(" STATUS_WORD (79h) = 0x0000 [clean]");
+ ut_assert_nextline(" STATUS_VOUT (7Ah) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_IOUT (7Bh) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_INPUT (7Ch) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_TEMP (7Dh) = 0x00 [clean]");
+ ut_assert_nextline(" STATUS_CML (7Eh) = 0x00 [clean]");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_status, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus read/pmbus write raw register access (byte, word, string) */
+static int dm_test_pmbus_read_write(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ /* Symbolic and numeric register names both resolve */
+ ut_assertok(run_command("pmbus read VOUT_MODE", 0));
+ ut_assert_nextline(" 20h VOUT_MODE b=0x18");
+ ut_assertok(run_command("pmbus read 0x8b w", 0));
+ ut_assert_nextline(" 8bh READ_VOUT w=0x0200");
+ ut_assertok(run_command("pmbus read MFR_ID s", 0));
+ ut_assert_nextline(" 99h MFR_ID s=\"SANDBOX\"");
+
+ /* A word write is observable on the next read-back */
+ ut_assertok(run_command("pmbus write VOUT_COMMAND 0x0123 w", 0));
+ ut_assert_nextline("pmbus: wrote 0x123 to 21h (VOUT_COMMAND)");
+ ut_assertok(run_command("pmbus read VOUT_COMMAND w", 0));
+ ut_assert_nextline(" 21h VOUT_COMMAND w=0x0123");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_read_write, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus vout reads back VOUT via the active driver_info decoder */
+static int dm_test_pmbus_vout(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus vout", 0));
+ ut_assert_nextline("pmbus VOUT @ i2c0:0x70 raw=0x0200 2.000V");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_vout, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus dump walks every standard register; spot-check one line */
+static int dm_test_pmbus_dump(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus dump", 0));
+ ut_assert_nextline("pmbus dump @ i2c0:0x70 (registers known to <pmbus.h>)");
+ ut_assert_skip_to_line(" 20h VOUT_MODE b=0x18");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_dump, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus clear [faults] issues CLEAR_FAULTS (03h) */
+static int dm_test_pmbus_clear(struct unit_test_state *uts)
+{
+ ut_assertok(pmbus_select(uts));
+
+ ut_assertok(run_command("pmbus clear faults", 0));
+ ut_assert_nextline("pmbus: CLEAR_FAULTS (03h) issued (RAM sticky STATUS_* cleared)");
+ ut_assert_console_end();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_clear, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus scan finds the emulated chip by its MFR_ID block read */
+static int dm_test_pmbus_scan(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus scan 0", 0));
+ ut_assert_skip_to_line(" i2c0:0x70 MFR_ID=\"SANDBOX\"");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_scan, UTF_SCAN_FDT | UTF_CONSOLE);
+
+/* pmbus help lists vendor extensions; none are registered here */
+static int dm_test_pmbus_help(struct unit_test_state *uts)
+{
+ ut_assertok(run_command("pmbus help", 0));
+ ut_assert_nextline("pmbus: no vendor extensions registered.");
+ ut_assert_skip_to_line(" board hook (boot snapshot) and re run 'pmbus help'.");
+ console_record_reset();
+
+ return 0;
+}
+
+DM_TEST(dm_test_pmbus_help, UTF_SCAN_FDT | UTF_CONSOLE);
--
2.43.0
^ permalink raw reply related [flat|nested] 24+ messages in thread
* Re: [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support
2026-07-02 17:26 ` [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Tom Rini
@ 2026-07-02 23:06 ` Vincent Jardin
0 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-02 23:06 UTC (permalink / raw)
To: Tom Rini
Cc: u-boot, Alexey Charkov, Alice Guo, Andrew Goodbody, Anshul Dalal,
Bo-Chen Chen, Brian Sune, David Lechner, Dinesh Maniyam,
Fabio Estevam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jaehoon Chung,
Jerome Forissier, Julien Masson, Julien Stephan, Kory Maincent,
Kuan-Wei Chiu, Lucien.Jheng, Macpaul Lin, Marek Vasut,
Marek Vasut, Martin Schwan, Mateusz Furdyna, Mattijs Korpershoek,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
NXP i.MX U-Boot Team, Neil Armstrong, Nobuhiro Iwamatsu, Peng Fan,
Peter Robinson, Philip Molloy, Pieter Van Trappen, Quentin Schulz,
Rasmus Villemoes, Raymond Mao, Simon Glass, Stefan Roese,
Stefano Babic, Svyatoslav Ryhel
Hi Tom,
> [snip]
> > .../regulator/lltc,ltc3882.yaml | 91 ++
> > .../regulator/mps,mpq8785.yaml | 105 +++
> > doc/device-tree-bindings/regulator/pmbus.yaml | 65 ++
> > .../regulator/renesas,isl68233.yaml | 105 +++
>
> We should be using, and referencing, the unmodified versions of these
> files in dts/upstream instead, thanks.
thanks for this feedback, I did miss it.
I sent a v2 using the upstream yaml files.
Best regards,
Vincent
PS: the v2 was sent thru 2 waves since I had some smtp issues.
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding
2026-07-02 19:56 ` [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
@ 2026-07-06 3:37 ` Peng Fan
2026-07-06 10:27 ` Vincent Jardin
0 siblings, 1 reply; 24+ messages in thread
From: Peng Fan @ 2026-07-06 3:37 UTC (permalink / raw)
To: Vincent Jardin
Cc: u-boot, Alexey Charkov, Andrew Goodbody, David Lechner,
Dinesh Maniyam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jerome Forissier,
Julien Stephan, Kory Maincent, Kuan-Wei Chiu, Marek Vasut,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
Neil Armstrong, Peng Fan, Peter Robinson, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
On Thu, Jul 02, 2026 at 09:56:03PM +0200, Vincent Jardin wrote:
>Add U-Boot's PMBus 1.x layer: the decoder/transport library, the
>pmbus CLI command and a generic DT binding.
>
>The subsequent commits provide the UCLASS_REGULATOR adapter and per-chip
>drivers.
>
...
>+ case PMBUS_MFR_REVISION: {
>+ char s[PMBUS_MFR_STRING_MAX];
>+
>+ if (pmbus_read_string(chip, reg, s, sizeof(s),
>+ act->info ? false : false) >= 0)
Should be true : false or false: true?
>+ printf(" %02xh %-15s s=\"%s\"\n",
>+ reg, pmbus_reg_syms[i].name, s);
>+
...
>+int pmbus_read_string(struct udevice *dev, u8 cmd, char *out, int outsz,
>+ bool reverse_bytes)
>+{
>+ u8 raw[PMBUS_MFR_STRING_MAX];
>+ int ret, len, i;
>+
>+ if (outsz < 2)
>+ return -EINVAL;
>+
>+ /* Stage 1: read the length byte. */
>+ ret = dm_i2c_read(dev, cmd, raw, 1);
>+ if (ret)
>+ return ret;
>+
>+ len = raw[0];
>+ if (len <= 0 || len > (int)sizeof(raw))
>+ return -EBADMSG;
>+ if (len > outsz - 1)
>+ len = outsz - 1;
>+
>+ /* Stage 2: reread length + payload (some controllers mandate this). */
>+ ret = dm_i2c_read(dev, cmd, raw, len + 1);
When len is 16, len + 1 bytes are read, so corrupt u8 raw[].
>+ if (ret)
>+ return ret;
>+
Regards
Peng
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support
2026-07-02 20:15 ` [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
@ 2026-07-06 3:41 ` Peng Fan
2026-07-06 10:32 ` Vincent Jardin
0 siblings, 1 reply; 24+ messages in thread
From: Peng Fan @ 2026-07-06 3:41 UTC (permalink / raw)
To: Vincent Jardin; +Cc: u-boot, sjg, trini
On Thu, Jul 02, 2026 at 10:15:42PM +0200, Vincent Jardin wrote:
>Wire board/nxp/common/vid.c into the <pmbus.h> framework so the legacy
>NXP AVS path stops carrying its own duplicate copy of the PMBus
>protocol and instead consumes the shared constants, decoders, and
>transport helpers.
>
>vid.c is the legacy NXP AVS/pre-kernel voltage-trim path for lx2160 CPUs.
>It does PMBus to whichever core-rail voltage monitor the board carries:
>LTC3882 or ISL68233 are selected with
>CONFIG_VOL_MONITOR_LTC3882_*/CONFIG_VOL_MONITOR_ISL68233_*.
>
>Before this change the file kept its own local PMBUS_CMD_* command-code
>defines, its own inline LINEAR16 mantissa/exponent math, and called
>into I2C through the I2C_READ/I2C_WRITE NXP wrappers in
>board/nxp/common/i2c_common.{c,h} which is a parallel implementation of
>exactly what <pmbus.h> + lib/pmbus.c provides.
>
>The intent is to make vid.c an consumer of the new PMBus.
>
>Compatibility with the former support:
>
> - CLI unchanged: vdd_override and vdd_read keep their existing
> semantics, return codes, and diagnostic output.
>
> - I2C transport unchanged on the wire: the framework's pmbus_*
> helpers call dm_i2c_read/dm_i2c_write: the same DM I2C
> backing that vid.c's former I2C_READ/I2C_WRITE macros already
> routed through on DM_I2C.
>
> - Numeric decode is bit-equivalent: pmbus_reg2data_linear16() and
> pmbus_data2reg_linear16() implement the PMBus 1.3 Part II
> mantissa/exponent.
>
>Signed-off-by: Vincent Jardin <vjardin@free.fr>
>---
>
>(no changes since v1)
>
> arch/Kconfig.nxp | 4 ++
> board/nxp/common/vid.c | 104 ++++++++++++++++++++++-------------------
> board/nxp/common/vid.h | 15 +++---
> 3 files changed, 68 insertions(+), 55 deletions(-)
>
>diff --git a/arch/Kconfig.nxp b/arch/Kconfig.nxp
>index ef9087d0197..152692e3230 100644
>--- a/arch/Kconfig.nxp
>+++ b/arch/Kconfig.nxp
>@@ -242,24 +242,28 @@ config VOL_MONITOR_IR36021_SET
>
> config VOL_MONITOR_LTC3882_READ
> bool "Enable the LTC3882 voltage monitor read"
>+ select PMBUS
> help
> This option enables LTC3882 voltage monitor read
> functionality. It is used by the common VID driver.
>
> config VOL_MONITOR_LTC3882_SET
> bool "Enable the LTC3882 voltage monitor set"
>+ select PMBUS
> help
> This option enables LTC3882 voltage monitor set
> functionality. It is used by the common VID driver.
>
> config VOL_MONITOR_ISL68233_READ
> bool "Enable the ISL68233 voltage monitor read"
>+ select PMBUS
> help
> This option enables ISL68233 voltage monitor read
> functionality. It is used by the common VID driver.
>
> config VOL_MONITOR_ISL68233_SET
> bool "Enable the ISL68233 voltage monitor set"
>+ select PMBUS
> help
> This option enables ISL68233 voltage monitor set
> functionality. It is used by the common VID driver.
>diff --git a/board/nxp/common/vid.c b/board/nxp/common/vid.c
>index 84cb43fad56..a91d6c9381a 100644
>--- a/board/nxp/common/vid.c
>+++ b/board/nxp/common/vid.c
>@@ -11,6 +11,7 @@
> #include <i2c.h>
> #include <irq_func.h>
> #include <log.h>
>+#include <pmbus.h>
> #include <vsprintf.h>
> #include <asm/io.h>
> #ifdef CONFIG_FSL_LSCH2
>@@ -260,45 +261,38 @@ static int read_voltage_from_IR(int i2caddress)
> */
> #define VOUT_WARNING "VID: VOUT_MODE exponent has resolution worse than 1 V!\n"
>
>-/* Checks the PMBus voltage monitor for the format used for voltage values */
>-static int get_pmbus_multiplier(DEVICE_HANDLE_T dev)
>+/*
>+ * Read VOUT_MODE for downstream LINEAR16 decode/encode through the
>+ * tree level <pmbus.h> helpers (pmbus_reg2data_linear16,
>+ * pmbus_data2reg_linear16). Returns the raw VOUT_MODE byte on
>+ * success, or 0 on bus error. Emits VOUT_WARNING on Linear mode
>+ * chips with a non negative exponent (resolution >= 1 V is unusable
>+ * for sub volt SoC rails) and an informational note on the
>+ * unsupported VID format.
>+ */
>+static u8 vid_read_vout_mode(DEVICE_HANDLE_T dev)
> {
>- u8 mode;
>- int exponent, multiplier, ret;
>+ u8 mode = 0;
>+ int ret;
>
>- ret = I2C_READ(dev, PMBUS_CMD_VOUT_MODE, &mode, sizeof(mode));
>+ ret = pmbus_read_byte(dev, PMBUS_VOUT_MODE, &mode);
> if (ret) {
> printf("VID: unable to determine voltage multiplier\n");
>- return 1;
>+ return 0;
> }
>
...
>+ /*
>+ * Decode LINEAR16 via the tree level helper from <pmbus.h>. For
>+ * non Linear VOUT_MODE settings the helper returns 0; fall back
>+ * to the historic mV pass through so existing LSCH boards keep.
>+ */
>+ vout_mode = vid_read_vout_mode(dev);
>+ if ((vout_mode & PB_VOUT_MODE_MODE_MASK) == PB_VOUT_MODE_LINEAR) {
>+ s64 uv = pmbus_reg2data_linear16(vcode, vout_mode);
>+
>+ vout = (int)((uv + 500) / 1000); /* round to mV */
>+ } else {
>+ vout = (int)vcode;
>+ }
> return vout - board_vdd_drop_compensation();
When vid_read_vout_mode() returns 0, the return value here seems
not correct.
> }
Regards,
Peng
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver
2026-07-02 20:14 ` [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
@ 2026-07-06 3:43 ` Peng Fan
2026-07-06 10:24 ` Vincent Jardin
0 siblings, 1 reply; 24+ messages in thread
From: Peng Fan @ 2026-07-06 3:43 UTC (permalink / raw)
To: Vincent Jardin; +Cc: u-boot, sjg, trini
On Thu, Jul 02, 2026 at 10:14:38PM +0200, Vincent Jardin wrote:
>Per-chip UCLASS_REGULATOR driver for the MPS MPQ8785 / MPM3695 /
>MPM3695-25 / MPM82504 family, layered on the shared pmbus_helper
>adapter. Runs Linux's mpq8785_identify() VOUT_MODE switch
>(LINEAR16 vs DIRECT m=64 R=1) at probe time, applies the optional
>mps,vout-fb-divider-ratio-permille DT property, and walks the
>documented MPS ADDR_VBOOT windows on MFR_ID failure so a
>die-revision address shift just works.
Per reading the driver, only one MPS[X] is supported here.
Are there cases that need multiple MPS?
>
>Publishes the pmbus mps last|clear last|clear force vendor
>extension subcommands (NVM PROTECTION_LAST read and clear) when
>CMD_PMBUS is enabled.
>
>Adaapted from Linux code.
Typo.
>
>Signed-off-by: Vincent Jardin <vjardin@free.fr>
>---
>
Regards
Peng
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver
2026-07-06 3:43 ` Peng Fan
@ 2026-07-06 10:24 ` Vincent Jardin
0 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-06 10:24 UTC (permalink / raw)
To: Peng Fan; +Cc: u-boot, sjg, trini
Hi Peng,
Thanks for your comments, see below.
> Per reading the driver, only one MPS[X] is supported here.
> Are there cases that need multiple MPS?
No, mulitiple MPS can be used and are supported, eaching having
its own i2c/bus addresses/DT node. For instance, you'd need a
MPS for the lx2160 and another MPS for an ASIC.
What is somehow unique is the CLI concept of "active" chip:
'pmbus dev'
selects one deviec for the following subcommands (telemetry,
status, dump, etc...).
In fact, it follows the same way than i2c dev or mmc dev that I
get inspired from.
> >Adaapted from Linux code.
>
> Typo.
Thanks, it'll be fixed into the v3 serie.
best regards,
Vincent
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding
2026-07-06 3:37 ` Peng Fan
@ 2026-07-06 10:27 ` Vincent Jardin
0 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-06 10:27 UTC (permalink / raw)
To: Peng Fan
Cc: u-boot, Alexey Charkov, Andrew Goodbody, David Lechner,
Dinesh Maniyam, Heiko Schocher, Heiko Stuebner,
Heinrich Schuchardt, Ilias Apalodimas, Jerome Forissier,
Julien Stephan, Kory Maincent, Kuan-Wei Chiu, Marek Vasut,
Michael Trimarchi, Michal Simek, Mikhail Kshevetskiy,
Neil Armstrong, Peng Fan, Peter Robinson, Philip Molloy,
Quentin Schulz, Raymond Mao, Simon Glass, Stefan Roese, Tom Rini
Hi Peng,
Below some feedbacks on you reviews. More will be provided into
a v3.
> >+ if (pmbus_read_string(chip, reg, s, sizeof(s),
> >+ act->info ? false : false) >= 0)
>
> Should be true : false or false: true?
hmm ;) it is a leftover, I'll clean it.
> >+ ret = dm_i2c_read(dev, cmd, raw, len + 1);
>
> When len is 16, len + 1 bytes are read, so corrupt u8 raw[].
right, I'll improve it for v3, thanks for detecting it.
best regards,
Vincent
^ permalink raw reply [flat|nested] 24+ messages in thread
* Re: [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support
2026-07-06 3:41 ` Peng Fan
@ 2026-07-06 10:32 ` Vincent Jardin
0 siblings, 0 replies; 24+ messages in thread
From: Vincent Jardin @ 2026-07-06 10:32 UTC (permalink / raw)
To: Peng Fan; +Cc: u-boot, sjg, trini
Hi Peng,
> When vid_read_vout_mode() returns 0, the return value here seems
> not correct.
thanks ! , fixed for the v3
^ permalink raw reply [flat|nested] 24+ messages in thread
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2026-07-02 19:56 ` [PATCH v2 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 19:56 ` [PATCH v2 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
2026-07-06 3:37 ` Peng Fan
2026-07-06 10:27 ` Vincent Jardin
2026-07-02 20:07 ` [PATCH v2 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
2026-07-02 20:14 ` [PATCH v2 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
2026-07-06 3:43 ` Peng Fan
2026-07-06 10:24 ` Vincent Jardin
2026-07-02 20:15 ` [PATCH v2 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
2026-07-06 3:41 ` Peng Fan
2026-07-06 10:32 ` Vincent Jardin
2026-07-02 22:26 ` [PATCH v2 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
2026-07-02 22:56 ` [PATCH v2 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
2026-07-02 22:57 ` [PATCH v2 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
2026-07-02 17:15 [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 1/7] pmbus: add PMBus 1.x framework, CLI, and binding Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 2/7] power: regulator: add generic PMBus UCLASS_REGULATOR adapter Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 3/7] power: regulator: add MPS MPQ8785 PMBus regulator driver Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 4/7] board: nxp: vid: introduce PMBus framework support Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 5/7] thermal: pmbus: add PMBus die-temp driver Vincent Jardin
2026-07-02 17:15 ` [PATCH v1 6/7] test: dm: pmbus: add a sandbox PMBus chip emulator Vincent Jardin
2026-07-02 17:26 ` [PATCH v1 0/7] pmbus: PMBus 1.x framework, CLI, regulator and thermal support Tom Rini
2026-07-02 23:06 ` Vincent Jardin
2026-07-02 17:46 ` [PATCH v1 7/7] test: dm: pmbus: test pmbus command and framework Vincent Jardin
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