* [PATCH 2/2] hwmon: add MPQ82D00 driver
2026-07-04 8:19 ` [PATCH 1/2] dt-bindings: hwmon: Add " wenswang
@ 2026-07-04 8:19 ` wenswang
2026-07-05 14:40 ` [PATCH 1/2] dt-bindings: hwmon: Add MPS mpq82d00 Conor Dooley
1 sibling, 0 replies; 4+ messages in thread
From: wenswang @ 2026-07-04 8:19 UTC (permalink / raw)
To: robh, krzk+dt, conor+dt, linux, corbet, skhan
Cc: devicetree, linux-kernel, linux-hwmon, linux-doc, Wensheng Wang
From: Wensheng Wang <wenswang@yeah.net>
Add support for MPS mpq82d00 controller. This driver exposes
telemetry and limit value readings and writtings.
Signed-off-by: Wensheng Wang <wenswang@yeah.net>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/mpq82d00.rst | 73 +++++++++
MAINTAINERS | 7 +
drivers/hwmon/pmbus/Kconfig | 9 ++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/mpq82d00.c | 249 +++++++++++++++++++++++++++++++
6 files changed, 340 insertions(+)
create mode 100644 Documentation/hwmon/mpq82d00.rst
create mode 100644 drivers/hwmon/pmbus/mpq82d00.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 29130df44d12..5d8cf2f60c27 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -201,6 +201,7 @@ Hardware Monitoring Kernel Drivers
mp5990
mp9941
mp9945
+ mpq82d00
mpq8785
nct6683
nct6775
diff --git a/Documentation/hwmon/mpq82d00.rst b/Documentation/hwmon/mpq82d00.rst
new file mode 100644
index 000000000000..5dc523042493
--- /dev/null
+++ b/Documentation/hwmon/mpq82d00.rst
@@ -0,0 +1,73 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mpq82d00
+====================
+
+Supported chips:
+
+ * MPS mpq82d00
+
+ Prefix: 'mpq82d00'
+
+Author:
+
+ Wensheng Wang <wenswang@yeah.net>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MPQ82D00 Step-Down Controller.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_crit**
+
+**curr1_crit_alarm**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+**power1_alarm**
+
+The driver provides the following attributes for output power:
+
+**power2_input**
+
+**power2_label**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
diff --git a/MAINTAINERS b/MAINTAINERS
index 15011f5752a9..c4cda9f664a1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18325,6 +18325,13 @@ S: Maintained
F: Documentation/hwmon/mp9945.rst
F: drivers/hwmon/pmbus/mp9945.c
+MPS MPQ82D00 DRIVER
+M: Wensheng Wang <wenswang@yeah.net>
+L: linux-hwmon@vger.kernel.org
+S: Maintained
+F: Documentation/hwmon/mpq82d00.rst
+F: drivers/hwmon/pmbus/mpq82d00.c
+
MR800 AVERMEDIA USB FM RADIO DRIVER
M: Alexey Klimov <alexey.klimov@linaro.org>
L: linux-media@vger.kernel.org
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index c8cda160b5f8..1804d366c2d9 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -607,6 +607,15 @@ config SENSORS_MPQ7932
This driver can also be built as a module. If so, the module will
be called mpq7932.
+config SENSORS_MPQ82D00
+ tristate "MPS MPQ82D00"
+ help
+ If you say yes here you get hardware monitoring functionality support
+ for power management IC MPS MPQ82D00.
+
+ This driver can also be built as a module. If so, the module will
+ be called mpq82d00.
+
config SENSORS_MPQ8785
tristate "MPS MPQ8785"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index ffc05f493213..31d62d01c3f0 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_SENSORS_MP5990) += mp5990.o
obj-$(CONFIG_SENSORS_MP9941) += mp9941.o
obj-$(CONFIG_SENSORS_MP9945) += mp9945.o
obj-$(CONFIG_SENSORS_MPQ7932) += mpq7932.o
+obj-$(CONFIG_SENSORS_MPQ82D00) += mpq82d00.o
obj-$(CONFIG_SENSORS_MPQ8785) += mpq8785.o
obj-$(CONFIG_SENSORS_PLI1209BC) += pli1209bc.o
obj-$(CONFIG_SENSORS_PM6764TR) += pm6764tr.o
diff --git a/drivers/hwmon/pmbus/mpq82d00.c b/drivers/hwmon/pmbus/mpq82d00.c
new file mode 100644
index 000000000000..a88a5ac5a363
--- /dev/null
+++ b/drivers/hwmon/pmbus/mpq82d00.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for MPS Synchronous Step-Down Converter(MPQ82D00)
+ */
+
+#include <linux/bitfield.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define MPQ82D00_VOUT_DIV 64
+
+#define MPQ82D00_PAGE_NUM 1
+
+#define MPQ82D00_RAIL1_FUNC (PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | \
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP | \
+ PMBUS_HAVE_POUT | PMBUS_HAVE_PIN | \
+ PMBUS_HAVE_STATUS_VOUT | \
+ PMBUS_HAVE_STATUS_IOUT | \
+ PMBUS_HAVE_STATUS_TEMP | \
+ PMBUS_HAVE_STATUS_INPUT)
+
+struct mpq82d00_data {
+ struct pmbus_driver_info info;
+ int vout_scale;
+};
+
+#define to_mpq82d00_data(x) container_of(x, struct mpq82d00_data, info)
+
+static u16 mpq82d00_linear_exp_transfer(u16 word, u16 expect_exponent)
+{
+ s16 exponent, mantissa, target_exponent;
+
+ exponent = ((s16)word) >> 11;
+ mantissa = ((s16)((word & 0x7ff) << 5)) >> 5;
+ target_exponent = (s16)((expect_exponent & 0x1f) << 11) >> 11;
+
+ /*
+ * The MPQ82D00 does not support negtive limit value, if a negtive
+ * limit value is written, the limit value will become to 0. And
+ * the maximum positive limit value is limitted to 0x3FF.
+ */
+ if (mantissa < 0) {
+ mantissa = 0;
+ } else {
+ if (exponent > target_exponent) {
+ mantissa = (1023 >> (exponent - target_exponent)) >= mantissa ?
+ mantissa << (exponent - target_exponent) :
+ 0x3FF;
+ } else {
+ mantissa = clamp_val(mantissa >> (target_exponent - exponent),
+ 0, 0x3FF);
+ }
+ }
+
+ return mantissa | ((expect_exponent << 11) & 0xf800);
+}
+
+static int mpq82d00_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+ int ret;
+
+ switch (reg) {
+ case PMBUS_VOUT_MODE:
+ /*
+ * The MPQ82D00 does not follow standard PMBus protocol completely,
+ * and the calculation of vout in this driver is based on direct
+ * format. As a result, the format of vout is enforced to direct.
+ */
+ ret = PB_VOUT_MODE_DIRECT;
+ break;
+ default:
+ /*
+ * These registers are not explicitly handled by the driver,
+ * as a result, return -ENODATA directly.
+ */
+ ret = -ENODATA;
+ break;
+ }
+
+ return ret;
+}
+
+static int mpq82d00_read_word_data(struct i2c_client *client, int page,
+ int phase, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct mpq82d00_data *data = to_mpq82d00_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_STATUS_WORD:
+ case PMBUS_READ_VIN:
+ case PMBUS_READ_IOUT:
+ case PMBUS_READ_POUT:
+ case PMBUS_READ_PIN:
+ case PMBUS_READ_TEMPERATURE_1:
+ case PMBUS_IOUT_OC_FAULT_LIMIT:
+ case PMBUS_OT_FAULT_LIMIT:
+ /*
+ * These registers are not explicitly handled by the driver,
+ * as a result, return -ENODATA directly.
+ */
+ ret = -ENODATA;
+ break;
+ case PMBUS_READ_VOUT:
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ if (ret < 0)
+ return ret;
+
+ ret = DIV_ROUND_CLOSEST((ret & GENMASK(11, 0)) * data->vout_scale,
+ MPQ82D00_VOUT_DIV);
+ break;
+ default:
+ /*
+ * The MPQ82D00 do not support other telemetry and limit
+ * value reading, so, return -EINVAL directly.
+ */
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static int mpq82d00_write_word_data(struct i2c_client *client, int page, int reg,
+ u16 word)
+{
+ int ret;
+
+ switch (reg) {
+ case PMBUS_OT_FAULT_LIMIT:
+ /*
+ * The PMBUS_OT_FAULT_LIMIT of MPQ82D00 is linear11 format,
+ * and the exponent is a constant value(5'b00000), so the
+ * exponent of word parameter should be converted to 5'b00000.
+ */
+ ret = pmbus_write_word_data(client, page, reg,
+ mpq82d00_linear_exp_transfer(word, 0x00));
+ break;
+ case PMBUS_IOUT_OC_FAULT_LIMIT:
+ /*
+ * The PMBUS_IOUT_OC_FAULT_LIMIT of MPQ82D00 is linear11 format,
+ * and the exponent is a constant value(5'b11100), so the
+ * exponent of word parameter should be converted to 5'b11100.
+ */
+ ret = pmbus_write_word_data(client, page, reg,
+ mpq82d00_linear_exp_transfer(word, 0x1C));
+ break;
+ default:
+ /*
+ * The MPQ82D00 do not support other limit value configuration,
+ * so, return -EINVAL directly.
+ */
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static int mpq82d00_identify(struct i2c_client *client, struct pmbus_driver_info *info)
+{
+ struct mpq82d00_data *data = to_mpq82d00_data(info);
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_byte_data(client, PMBUS_VOUT_MODE);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * The MPQ82D00 supports three vout mode. If PMBUS_VOUT_MODE
+ * bit5 is 1, the vout scale is 5mv/LSB.If PMBUS_VOUT_MODE bit5
+ * is 0, it is linear mode, the vout scale is 1.953125mv/LSB.
+ */
+ if (FIELD_GET(GENMASK(5, 5), ret))
+ data->vout_scale = 320;
+ else
+ data->vout_scale = 125;
+
+ return 0;
+}
+
+static struct pmbus_driver_info mpq82d00_info = {
+ .pages = MPQ82D00_PAGE_NUM,
+ .format[PSC_VOLTAGE_IN] = linear,
+ .format[PSC_CURRENT_OUT] = linear,
+ .format[PSC_TEMPERATURE] = linear,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_POWER] = linear,
+
+ .m[PSC_VOLTAGE_OUT] = 1,
+ .R[PSC_VOLTAGE_OUT] = 3,
+ .b[PSC_VOLTAGE_OUT] = 0,
+
+ .func[0] = MPQ82D00_RAIL1_FUNC,
+ .read_word_data = mpq82d00_read_word_data,
+ .read_byte_data = mpq82d00_read_byte_data,
+ .write_word_data = mpq82d00_write_word_data,
+ .identify = mpq82d00_identify,
+};
+
+static int mpq82d00_probe(struct i2c_client *client)
+{
+ struct mpq82d00_data *data;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct mpq82d00_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ memcpy(&data->info, &mpq82d00_info, sizeof(mpq82d00_info));
+
+ return pmbus_do_probe(client, &data->info);
+}
+
+static const struct i2c_device_id mpq82d00_id[] = {
+ {.name = "mpq82d00"},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, mpq82d00_id);
+
+static const struct of_device_id __maybe_unused mpq82d00_of_match[] = {
+ {.compatible = "mps,mpq82d00"},
+ {}
+};
+MODULE_DEVICE_TABLE(of, mpq82d00_of_match);
+
+static struct i2c_driver mpq82d00_driver = {
+ .driver = {
+ .name = "mpq82d00",
+ .of_match_table = mpq82d00_of_match,
+ },
+ .probe = mpq82d00_probe,
+ .id_table = mpq82d00_id,
+};
+
+module_i2c_driver(mpq82d00_driver);
+
+MODULE_AUTHOR("Wensheng Wang <wenswang@yeah.net");
+MODULE_DESCRIPTION("PMBus driver for MPS MPQ82D00 device");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.25.1
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