* [PATCH v9 2/3] hwmon: ltc4283: Add support for the LTC4283 Swap Controller
From: Nuno Sá via B4 Relay @ 2026-04-06 14:31 UTC (permalink / raw)
To: linux-gpio, linux-hwmon, devicetree, linux-doc
Cc: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Linus Walleij, Bartosz Golaszewski
In-Reply-To: <20260406-ltc4283-support-v9-0-b66cfc749261@analog.com>
From: Nuno Sá <nuno.sa@analog.com>
Support the LTC4283 Hot Swap Controller. The device features programmable
current limit with foldback and independently adjustable inrush current to
optimize the MOSFET safe operating area (SOA). The SOA timer limits MOSFET
temperature rise for reliable protection against overstresses.
An I2C interface and onboard ADC allow monitoring of board current,
voltage, power, energy, and fault status.
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/ltc4283.rst | 266 ++++++
MAINTAINERS | 1 +
drivers/hwmon/Kconfig | 12 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/ltc4283.c | 1808 +++++++++++++++++++++++++++++++++++++++
6 files changed, 2089 insertions(+)
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 199f35a75282..d54dda83ab6e 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -144,6 +144,7 @@ Hardware Monitoring Kernel Drivers
ltc4260
ltc4261
ltc4282
+ ltc4283
ltc4286
macsmc-hwmon
max127
diff --git a/Documentation/hwmon/ltc4283.rst b/Documentation/hwmon/ltc4283.rst
new file mode 100644
index 000000000000..ba88445e45f4
--- /dev/null
+++ b/Documentation/hwmon/ltc4283.rst
@@ -0,0 +1,266 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+Kernel drivers ltc4283
+==========================================
+
+Supported chips:
+
+ * Analog Devices LTC4283
+
+ Prefix: 'ltc4283'
+
+ Addresses scanned: -
+
+ Datasheet:
+
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4283.pdf
+
+Author: Nuno Sá <nuno.sa@analog.com>
+
+Description
+___________
+
+The LTC4283 negative voltage hot swap controller drives an external N-channel
+MOSFET to allow a board to be safely inserted and removed from a live backplane.
+The device features programmable current limit with foldback and independently
+adjustable inrush current to optimize the MOSFET safe operating area (SOA). The
+SOA timer limits MOSFET temperature rise for reliable protection against
+overstresses. An I2C interface and onboard gear-shift ADC allow monitoring of
+board current, voltage, power, energy, and fault status. Additional features
+respond to input UV/OV, interrupt the host when a fault has occurred, notify
+when output power is good, detect insertion of a board, turn off the MOSFET
+if an external supply monitor fails to indicate power good within a timeout
+period, and auto-reboot after a programmable delay following a host commanded
+turn-off.
+
+Sysfs entries
+_____________
+
+The following attributes are supported. Limits are read-write and all the other
+attributes are read-only. Note that the VADIOx channels might not be available
+if the ADIO pins are used as GPIOs (naturally also affects the respective
+differential channels).
+
+======================= ==========================================
+in0_lcrit_alarm Critical Undervoltage alarm
+in0_crit_alarm Critical Overvoltage alarm
+in0_label Channel label (VIN)
+
+in1_input Output voltage (mV).
+in1_min Undervoltage threshold
+in1_max Overvoltage threshold
+in1_lowest Lowest measured voltage
+in1_highest Highest measured voltage
+in1_reset_history Write 1 to reset history.
+in1_min_alarm Undervoltage alarm
+in1_max_alarm Overvoltage alarm
+in1_label Channel label (VPWR)
+
+in2_input Output voltage (mV).
+in2_min Undervoltage threshold
+in2_max Overvoltage threshold
+in2_lowest Lowest measured voltage
+in2_highest Highest measured voltage
+in2_reset_history Write 1 to reset history.
+in2_min_alarm Undervoltage alarm
+in2_max_alarm Overvoltage alarm
+in2_enable Enable/Disable monitoring.
+in2_label Channel label (VADI1)
+
+in3_input Output voltage (mV).
+in3_min Undervoltage threshold
+in3_max Overvoltage threshold
+in3_lowest Lowest measured voltage
+in3_highest Highest measured voltage
+in3_reset_history Write 1 to reset history.
+in3_min_alarm Undervoltage alarm
+in3_max_alarm Overvoltage alarm
+in3_enable Enable/Disable monitoring.
+in3_label Channel label (VADI2)
+
+in4_input Output voltage (mV).
+in4_min Undervoltage threshold
+in4_max Overvoltage threshold
+in4_lowest Lowest measured voltage
+in4_highest Highest measured voltage
+in4_reset_history Write 1 to reset history.
+in4_min_alarm Undervoltage alarm
+in4_max_alarm Overvoltage alarm
+in4_enable Enable/Disable monitoring.
+in4_label Channel label (VADI3)
+
+in5_input Output voltage (mV).
+in5_min Undervoltage threshold
+in5_max Overvoltage threshold
+in5_lowest Lowest measured voltage
+in5_highest Highest measured voltage
+in5_reset_history Write 1 to reset history.
+in5_min_alarm Undervoltage alarm
+in5_max_alarm Overvoltage alarm
+in5_enable Enable/Disable monitoring.
+in5_label Channel label (VADI4)
+
+in6_input Output voltage (mV).
+in6_min Undervoltage threshold
+in6_max Overvoltage threshold
+in6_lowest Lowest measured voltage
+in6_highest Highest measured voltage
+in6_reset_history Write 1 to reset history.
+in6_min_alarm Undervoltage alarm
+in6_max_alarm Overvoltage alarm
+in6_enable Enable/Disable monitoring.
+in6_label Channel label (VADIO1)
+
+in7_input Output voltage (mV).
+in7_min Undervoltage threshold
+in7_max Overvoltage threshold
+in7_lowest Lowest measured voltage
+in7_highest Highest measured voltage
+in7_reset_history Write 1 to reset history.
+in7_min_alarm Undervoltage alarm
+in7_max_alarm Overvoltage alarm
+in7_enable Enable/Disable monitoring.
+in7_label Channel label (VADIO2)
+
+in8_input Output voltage (mV).
+in8_min Undervoltage threshold
+in8_max Overvoltage threshold
+in8_lowest Lowest measured voltage
+in8_highest Highest measured voltage
+in8_reset_history Write 1 to reset history.
+in8_min_alarm Undervoltage alarm
+in8_max_alarm Overvoltage alarm
+in8_enable Enable/Disable monitoring.
+in8_label Channel label (VADIO3)
+
+in9_input Output voltage (mV).
+in9_min Undervoltage threshold
+in9_max Overvoltage threshold
+in9_lowest Lowest measured voltage
+in9_highest Highest measured voltage
+in9_reset_history Write 1 to reset history.
+in9_min_alarm Undervoltage alarm
+in9_max_alarm Overvoltage alarm
+in9_enable Enable/Disable monitoring.
+in9_label Channel label (VADIO4)
+
+in10_input Output voltage (mV).
+in10_min Undervoltage threshold
+in10_max Overvoltage threshold
+in10_lowest Lowest measured voltage
+in10_highest Highest measured voltage
+in10_reset_history Write 1 to reset history.
+in10_min_alarm Undervoltage alarm
+in10_max_alarm Overvoltage alarm
+in10_enable Enable/Disable monitoring.
+in10_label Channel label (DRNS)
+
+in11_input Output voltage (mV).
+in11_min Undervoltage threshold
+in11_max Overvoltage threshold
+in11_lowest Lowest measured voltage
+in11_highest Highest measured voltage
+in11_reset_history Write 1 to reset history.
+ Also clears fet bad and short fault logs.
+in11_min_alarm Undervoltage alarm
+in11_max_alarm Overvoltage alarm
+in11_enable Enable/Disable monitoring
+in11_fault Failure in the MOSFET. Either bad or shorted FET.
+in11_label Channel label (DRAIN)
+
+in12_input Output voltage (mV).
+in12_min Undervoltage threshold
+in12_max Overvoltage threshold
+in12_lowest Lowest measured voltage
+in12_highest Highest measured voltage
+in12_reset_history Write 1 to reset history.
+in12_min_alarm Undervoltage alarm
+in12_max_alarm Overvoltage alarm
+in12_enable Enable/Disable monitoring.
+in12_label Channel label (ADIN2-ADIN1)
+
+in13_input Output voltage (mV).
+in13_min Undervoltage threshold
+in13_max Overvoltage threshold
+in13_lowest Lowest measured voltage
+in13_highest Highest measured voltage
+in13_reset_history Write 1 to reset history.
+in13_min_alarm Undervoltage alarm
+in13_max_alarm Overvoltage alarm
+in13_enable Enable/Disable monitoring.
+in13_label Channel label (ADIN4-ADIN3)
+
+in14_input Output voltage (mV).
+in14_min Undervoltage threshold
+in14_max Overvoltage threshold
+in14_lowest Lowest measured voltage
+in14_highest Highest measured voltage
+in14_reset_history Write 1 to reset history.
+in14_min_alarm Undervoltage alarm
+in14_max_alarm Overvoltage alarm
+in14_enable Enable/Disable monitoring.
+in14_label Channel label (ADIO2-ADIO1)
+
+in15_input Output voltage (mV).
+in15_min Undervoltage threshold
+in15_max Overvoltage threshold
+in15_lowest Lowest measured voltage
+in15_highest Highest measured voltage
+in15_reset_history Write 1 to reset history.
+in15_min_alarm Undervoltage alarm
+in15_max_alarm Overvoltage alarm
+in15_enable Enable/Disable monitoring.
+in15_label Channel label (ADIO4-ADIO3)
+
+curr1_input Sense current (mA)
+curr1_min Undercurrent threshold
+curr1_max Overcurrent threshold
+curr1_lowest Lowest measured current
+curr1_highest Highest measured current
+curr1_reset_history Write 1 to reset curr1 history.
+ Also clears overcurrent fault logs.
+curr1_min_alarm Undercurrent alarm
+curr1_max_alarm Overcurrent alarm
+curr1_crit_alarm Critical Overcurrent alarm
+curr1_label Channel label (ISENSE)
+
+power1_input Power (in uW)
+power1_min Low power threshold
+power1_max High power threshold
+power1_input_lowest Historical minimum power use
+power1_input_highest Historical maximum power use
+power1_reset_history Write 1 to reset power1 history.
+ Also clears power fault logs.
+power1_min_alarm Low power alarm
+power1_max_alarm High power alarm
+power1_label Channel label (Power)
+
+energy1_input Measured energy over time (in microJoule)
+energy1_enable Enable/Disable Energy accumulation
+======================= ==========================================
+
+DebugFs entries
+_______________
+
+The chip also has a fault log register where failures can be logged. Hence,
+as these are logging events, we give access to them in debugfs. Note that
+even if some failure is detected in these logs, it does necessarily mean
+that the failure is still present. As mentioned in the proper Sysfs entries,
+these logs can be cleared by writing in the proper reset_history attribute.
+
+.. warning:: The debugfs interface is subject to change without notice
+ and is only available when the kernel is compiled with
+ ``CONFIG_DEBUG_FS`` defined.
+
+``/sys/kernel/debug/i2c/i2c-[X]/[X]-addr/``
+contains the following attributes:
+
+======================= ==========================================
+power1_failed_fault_log Set to 1 by a power1 fault occurring.
+power1_good_input_fault_log Set to 1 by a power1 good input fault occurring at PGIO3.
+in11_fet_short_fault_log Set to 1 when a FET-short fault occurs.
+in11_fet_bad_fault_log Set to 1 when a FET-BAD fault occurs.
+in0_lcrit_fault_log Set to 1 by a VIN undervoltage fault occurring.
+in0_crit_fault_log Set to 1 by a VIN overvoltage fault occurring.
+curr1_crit_fault_log Set to 1 by an overcurrent fault occurring.
+======================= ==========================================
diff --git a/MAINTAINERS b/MAINTAINERS
index 3f727d7fdfa4..a63833b6fe8b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15166,6 +15166,7 @@ M: Nuno Sá <nuno.sa@analog.com>
L: linux-hwmon@vger.kernel.org
S: Supported
F: Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml
+F: drivers/hwmon/ltc4283.c
LTC4286 HARDWARE MONITOR DRIVER
M: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index fb847ab40ab4..4d9f500ae6ee 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1157,6 +1157,18 @@ config SENSORS_LTC4282
This driver can also be built as a module. If so, the module will
be called ltc4282.
+config SENSORS_LTC4283
+ tristate "Analog Devices LTC4283"
+ depends on I2C
+ select REGMAP_I2C
+ select AUXILIARY_BUS
+ help
+ If you say yes here you get support for Analog Devices LTC4283
+ Negative Voltage Hot Swap Controller I2C interface.
+
+ This driver can also be built as a module. If so, the module will
+ be called ltc4283.
+
config SENSORS_LTQ_CPUTEMP
bool "Lantiq cpu temperature sensor driver"
depends on SOC_XWAY
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 0fce31b43eb1..b9d7b0287b9c 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -147,6 +147,7 @@ obj-$(CONFIG_SENSORS_LTC4245) += ltc4245.o
obj-$(CONFIG_SENSORS_LTC4260) += ltc4260.o
obj-$(CONFIG_SENSORS_LTC4261) += ltc4261.o
obj-$(CONFIG_SENSORS_LTC4282) += ltc4282.o
+obj-$(CONFIG_SENSORS_LTC4283) += ltc4283.o
obj-$(CONFIG_SENSORS_LTQ_CPUTEMP) += ltq-cputemp.o
obj-$(CONFIG_SENSORS_MACSMC_HWMON) += macsmc-hwmon.o
obj-$(CONFIG_SENSORS_MAX1111) += max1111.o
diff --git a/drivers/hwmon/ltc4283.c b/drivers/hwmon/ltc4283.c
new file mode 100644
index 000000000000..2a2674a55167
--- /dev/null
+++ b/drivers/hwmon/ltc4283.c
@@ -0,0 +1,1808 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices LTC4283 I2C Negative Voltage Hot Swap Controller (HWMON)
+ *
+ * Copyright 2025 Analog Devices Inc.
+ */
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/bits.h>
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/device/devres.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/math.h>
+#include <linux/math64.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+
+#include <linux/mod_devicetable.h>
+#include <linux/overflow.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/unaligned.h>
+#include <linux/units.h>
+
+#define LTC4283_SYSTEM_STATUS 0x00
+#define LTC4283_FAULT_STATUS 0x03
+#define LTC4283_OV_MASK BIT(0)
+#define LTC4283_UV_MASK BIT(1)
+#define LTC4283_OC_MASK BIT(2)
+#define LTC4283_FET_BAD_MASK BIT(3)
+#define LTC4283_FET_SHORT_MASK BIT(6)
+#define LTC4283_FAULT_LOG 0x04
+#define LTC4283_OV_FAULT_MASK BIT(0)
+#define LTC4283_UV_FAULT_MASK BIT(1)
+#define LTC4283_OC_FAULT_MASK BIT(2)
+#define LTC4283_FET_BAD_FAULT_MASK BIT(3)
+#define LTC4283_PGI_FAULT_MASK BIT(4)
+#define LTC4283_PWR_FAIL_FAULT_MASK BIT(5)
+#define LTC4283_FET_SHORT_FAULT_MASK BIT(6)
+#define LTC4283_ADC_ALM_LOG_1 0x05
+#define LTC4283_POWER_LOW_ALM BIT(0)
+#define LTC4283_POWER_HIGH_ALM BIT(1)
+#define LTC4283_SENSE_LOW_ALM BIT(4)
+#define LTC4283_SENSE_HIGH_ALM BIT(5)
+#define LTC4283_ADC_ALM_LOG_2 0x06
+#define LTC4283_ADC_ALM_LOG_3 0x07
+#define LTC4283_ADC_ALM_LOG_4 0x08
+#define LTC4283_ADC_ALM_LOG_5 0x09
+#define LTC4283_CONTROL_1 0x0a
+#define LTC4283_RW_PAGE_MASK BIT(0)
+#define LTC4283_PIGIO2_ACLB_MASK BIT(2)
+#define LTC4283_PWRGD_RST_CTRL_MASK BIT(3)
+#define LTC4283_FET_BAD_OFF_MASK BIT(4)
+#define LTC4283_THERM_TMR_MASK BIT(5)
+#define LTC4283_DVDT_MASK BIT(6)
+#define LTC4283_CONTROL_2 0x0b
+#define LTC4283_OV_RETRY_MASK BIT(0)
+#define LTC4283_UV_RETRY_MASK BIT(1)
+#define LTC4283_OC_RETRY_MASK GENMASK(3, 2)
+#define LTC4283_FET_BAD_RETRY_MASK GENMASK(5, 4)
+#define LTC4283_EXT_FAULT_RETRY_MASK BIT(7)
+#define LTC4283_RESERVED_OC 0x0c
+#define LTC4283_CONFIG_1 0x0d
+#define LTC4283_FB_MASK GENMASK(3, 2)
+#define LTC4283_ILIM_MASK GENMASK(7, 4)
+#define LTC4283_CONFIG_2 0x0e
+#define LTC4283_COOLING_DL_MASK GENMASK(3, 1)
+#define LTC4283_FTBD_DL_MASK GENMASK(5, 4)
+#define LTC4283_CONFIG_3 0x0f
+#define LTC4283_VPWR_DRNS_MASK BIT(6)
+#define LTC4283_EXTFLT_TURN_OFF_MASK BIT(7)
+#define LTC4283_PGIO_CONFIG 0x10
+#define LTC4283_PGIO1_CFG_MASK GENMASK(1, 0)
+#define LTC4283_PGIO2_CFG_MASK GENMASK(3, 2)
+#define LTC4283_PGIO3_CFG_MASK GENMASK(5, 4)
+#define LTC4283_PGIO4_CFG_MASK GENMASK(7, 6)
+#define LTC4283_PGIO_CONFIG_2 0x11
+#define LTC4283_ADC_MASK GENMASK(2, 0)
+#define LTC4283_ADC_SELECT(c) (0x13 + (c) / 8)
+#define LTC4283_ADC_SELECT_MASK(c) BIT((c) % 8)
+#define LTC4283_SENSE_MIN_TH 0x1b
+#define LTC4283_SENSE_MAX_TH 0x1c
+#define LTC4283_VPWR_MIN_TH 0x1d
+#define LTC4283_VPWR_MAX_TH 0x1e
+#define LTC4283_POWER_MIN_TH 0x1f
+#define LTC4283_POWER_MAX_TH 0x20
+#define LTC4283_ADC_2_MIN_TH(c) (0x21 + (c) * 2)
+#define LTC4283_ADC_2_MAX_TH(c) (0x22 + (c) * 2)
+#define LTC4283_ADC_2_MIN_TH_DIFF(c) (0x39 + (c) * 2)
+#define LTC4283_ADC_2_MAX_TH_DIFF(c) (0x3a + (c) * 2)
+#define LTC4283_SENSE 0x41
+#define LTC4283_SENSE_MIN 0x42
+#define LTC4283_SENSE_MAX 0x43
+#define LTC4283_VPWR 0x44
+#define LTC4283_VPWR_MIN 0x45
+#define LTC4283_VPWR_MAX 0x46
+#define LTC4283_POWER 0x47
+#define LTC4283_POWER_MIN 0x48
+#define LTC4283_POWER_MAX 0x49
+#define LTC4283_RESERVED_68 0x68
+#define LTC4283_RESERVED_6D 0x6D
+/* get channels from ADC 2 */
+#define LTC4283_ADC_2(c) (0x4a + (c) * 3)
+#define LTC4283_ADC_2_MIN(c) (0x4b + (c) * 3)
+#define LTC4283_ADC_2_MAX(c) (0x4c + (c) * 3)
+#define LTC4283_ADC_2_DIFF(c) (0x6e + (c) * 3)
+#define LTC4283_ADC_2_MIN_DIFF(c) (0x6f + (c) * 3)
+#define LTC4283_ADC_2_MAX_DIFF(c) (0x70 + (c) * 3)
+#define LTC4283_ENERGY 0x7a
+#define LTC4283_METER_CONTROL 0x84
+#define LTC4283_INTEGRATE_I_MASK BIT(0)
+#define LTC4283_METER_HALT_MASK BIT(6)
+#define LTC4283_RESERVED_86 0x86
+#define LTC4283_RESERVED_8F 0x8F
+#define LTC4283_FAULT_LOG_CTRL 0x90
+#define LTC4283_FAULT_LOG_EN_MASK BIT(7)
+#define LTC4283_RESERVED_91 0x91
+#define LTC4283_RESERVED_A1 0xA1
+#define LTC4283_RESERVED_A3 0xA3
+#define LTC4283_RESERVED_AC 0xAC
+#define LTC4283_POWER_PLAY_MSB 0xE7
+#define LTC4283_POWER_PLAY_LSB 0xE8
+#define LTC4283_RESERVED_F1 0xF1
+#define LTC4283_RESERVED_FF 0xFF
+
+/* also applies for differential channels */
+#define LTC4283_ADC1_FS_uV 32768
+#define LTC4283_ADC2_FS_mV 2048
+#define LTC4283_TCONV_uS 64103
+#define LTC4283_VILIM_MIN_uV 15000
+#define LTC4283_VILIM_MAX_uV 30000
+#define LTC4283_VILIM_RANGE \
+ (LTC4283_VILIM_MAX_uV - LTC4283_VILIM_MIN_uV + 1)
+
+#define LTC4283_PGIO_FUNC_GPIO 2
+#define LTC4283_PGIO2_FUNC_ACLB 3
+
+/*
+ * Maximum value for rsense in nano ohms. The reasoning for this value is that
+ * it's the max value for which multiplying by 256 does not overflow long on
+ * 32bits. For the minimum value, is a sane minimum rsense for which power_max
+ * does not overflow 32bits.
+ */
+#define LTC4283_MAX_RSENSE 1677721599
+#define LTC4283_MIN_RSENSE 50000
+
+/* voltage channels */
+enum {
+ LTC4283_CHAN_VIN,
+ LTC4283_CHAN_VPWR,
+ LTC4283_CHAN_ADI_1,
+ LTC4283_CHAN_ADI_2,
+ LTC4283_CHAN_ADI_3,
+ LTC4283_CHAN_ADI_4,
+ LTC4283_CHAN_ADIO_1,
+ LTC4283_CHAN_ADIO_2,
+ LTC4283_CHAN_ADIO_3,
+ LTC4283_CHAN_ADIO_4,
+ LTC4283_CHAN_DRNS,
+ LTC4283_CHAN_DRAIN,
+ /* differential channels */
+ LTC4283_CHAN_ADIN12,
+ LTC4283_CHAN_ADIN34,
+ LTC4283_CHAN_ADIO12,
+ LTC4283_CHAN_ADIO34,
+ LTC4283_CHAN_MAX
+};
+
+/* Just for ease of use on the regmap */
+#define LTC4283_ADIO34_MAX \
+ LTC4283_ADC_2_MAX_DIFF(LTC4283_CHAN_ADIO34 - LTC4283_CHAN_ADIN12)
+
+struct ltc4283_hwmon {
+ struct regmap *map;
+ struct i2c_client *client;
+ unsigned long gpio_mask;
+ unsigned long ch_enable_mask;
+ /* in microwatt */
+ long power_max;
+ /* in millivolt */
+ u32 vsense_max;
+ /* in tenths of microohm*/
+ u32 rsense;
+ bool energy_en;
+ bool ext_fault;
+};
+
+static int ltc4283_read_voltage_word(const struct ltc4283_hwmon *st,
+ u32 reg, u32 fs, long *val)
+{
+ unsigned int __raw;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &__raw);
+ if (ret)
+ return ret;
+
+ *val = DIV_ROUND_CLOSEST(__raw * fs, BIT(16));
+ return 0;
+}
+
+static int ltc4283_read_voltage_byte(const struct ltc4283_hwmon *st,
+ u32 reg, u32 fs, long *val)
+{
+ int ret;
+ u32 in;
+
+ ret = regmap_read(st->map, reg, &in);
+ if (ret)
+ return ret;
+
+ *val = DIV_ROUND_CLOSEST(in * fs, BIT(8));
+ return 0;
+}
+
+static u32 ltc4283_in_reg(u32 attr, u32 channel)
+{
+ switch (attr) {
+ case hwmon_in_input:
+ if (channel == LTC4283_CHAN_VPWR)
+ return LTC4283_VPWR;
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN)
+ return LTC4283_ADC_2(channel - LTC4283_CHAN_ADI_1);
+ return LTC4283_ADC_2_DIFF(channel - LTC4283_CHAN_ADIN12);
+ case hwmon_in_highest:
+ if (channel == LTC4283_CHAN_VPWR)
+ return LTC4283_VPWR_MAX;
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN)
+ return LTC4283_ADC_2_MAX(channel - LTC4283_CHAN_ADI_1);
+ return LTC4283_ADC_2_MAX_DIFF(channel - LTC4283_CHAN_ADIN12);
+ case hwmon_in_lowest:
+ if (channel == LTC4283_CHAN_VPWR)
+ return LTC4283_VPWR_MIN;
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN)
+ return LTC4283_ADC_2_MIN(channel - LTC4283_CHAN_ADI_1);
+ return LTC4283_ADC_2_MIN_DIFF(channel - LTC4283_CHAN_ADIN12);
+ case hwmon_in_max:
+ if (channel == LTC4283_CHAN_VPWR)
+ return LTC4283_VPWR_MAX_TH;
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN)
+ return LTC4283_ADC_2_MAX_TH(channel - LTC4283_CHAN_ADI_1);
+ return LTC4283_ADC_2_MAX_TH_DIFF(channel - LTC4283_CHAN_ADIN12);
+ default:
+ if (channel == LTC4283_CHAN_VPWR)
+ return LTC4283_VPWR_MIN_TH;
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN)
+ return LTC4283_ADC_2_MIN_TH(channel - LTC4283_CHAN_ADI_1);
+ return LTC4283_ADC_2_MIN_TH_DIFF(channel - LTC4283_CHAN_ADIN12);
+ }
+}
+
+static int ltc4283_read_in_vals(const struct ltc4283_hwmon *st,
+ u32 attr, u32 channel, long *val)
+{
+ u32 reg = ltc4283_in_reg(attr, channel);
+ int ret;
+
+ if (channel < LTC4283_CHAN_ADIN12) {
+ if (attr != hwmon_in_max && attr != hwmon_in_min)
+ return ltc4283_read_voltage_word(st, reg,
+ LTC4283_ADC2_FS_mV,
+ val);
+
+ return ltc4283_read_voltage_byte(st, reg,
+ LTC4283_ADC2_FS_mV, val);
+ }
+
+ if (attr != hwmon_in_max && attr != hwmon_in_min)
+ ret = ltc4283_read_voltage_word(st, reg,
+ LTC4283_ADC1_FS_uV, val);
+ else
+ ret = ltc4283_read_voltage_byte(st, reg,
+ LTC4283_ADC1_FS_uV, val);
+ if (ret)
+ return ret;
+
+ *val = DIV_ROUND_CLOSEST(*val, MILLI);
+ return 0;
+}
+
+static int ltc4283_read_alarm(struct ltc4283_hwmon *st, u32 reg,
+ u32 mask, long *val)
+{
+ u32 alarm;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &alarm);
+ if (ret)
+ return ret;
+
+ *val = !!(alarm & mask);
+
+ /* If not status/fault logs, clear the alarm after reading it. */
+ if (reg != LTC4283_FAULT_STATUS && reg != LTC4283_FAULT_LOG)
+ return regmap_clear_bits(st->map, reg, mask);
+
+ return 0;
+}
+
+static int ltc4283_read_in_alarm(struct ltc4283_hwmon *st, u32 channel,
+ bool max_alm, long *val)
+{
+ if (channel == LTC4283_VPWR)
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_1,
+ BIT(2 + max_alm), val);
+
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_ADI_4) {
+ u32 bit = (channel - LTC4283_CHAN_ADI_1) * 2;
+ /*
+ * Lower channels go to higher bits. We also want to go +1 down
+ * in the min_alarm case.
+ */
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_2,
+ BIT(7 - bit - !max_alm), val);
+ }
+
+ if (channel >= LTC4283_CHAN_ADIO_1 && channel <= LTC4283_CHAN_ADIO_4) {
+ u32 bit = (channel - LTC4283_CHAN_ADIO_1) * 2;
+
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_3,
+ BIT(7 - bit - !max_alm), val);
+ }
+
+ if (channel >= LTC4283_CHAN_ADIN12 && channel <= LTC4283_CHAN_ADIO34) {
+ u32 bit = (channel - LTC4283_CHAN_ADIN12) * 2;
+
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_5,
+ BIT(7 - bit - !max_alm), val);
+ }
+
+ if (channel == LTC4283_CHAN_DRNS)
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_4,
+ BIT(6 + max_alm), val);
+
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_4, BIT(4 + max_alm),
+ val);
+}
+
+static int ltc4283_read_in(struct ltc4283_hwmon *st, u32 attr, u32 channel,
+ long *val)
+{
+ switch (attr) {
+ case hwmon_in_input:
+ if (!test_bit(channel, &st->ch_enable_mask))
+ return -ENODATA;
+
+ return ltc4283_read_in_vals(st, attr, channel, val);
+ case hwmon_in_highest:
+ case hwmon_in_lowest:
+ case hwmon_in_max:
+ case hwmon_in_min:
+ return ltc4283_read_in_vals(st, attr, channel, val);
+ case hwmon_in_max_alarm:
+ return ltc4283_read_in_alarm(st, channel, true, val);
+ case hwmon_in_min_alarm:
+ return ltc4283_read_in_alarm(st, channel, false, val);
+ case hwmon_in_crit_alarm:
+ return ltc4283_read_alarm(st, LTC4283_FAULT_STATUS,
+ LTC4283_OV_MASK, val);
+ case hwmon_in_lcrit_alarm:
+ return ltc4283_read_alarm(st, LTC4283_FAULT_STATUS,
+ LTC4283_UV_MASK, val);
+ case hwmon_in_fault:
+ /*
+ * We report failure if we detect either a fer_bad or a
+ * fet_short in the status register.
+ */
+ return ltc4283_read_alarm(st, LTC4283_FAULT_STATUS,
+ LTC4283_FET_BAD_MASK | LTC4283_FET_SHORT_MASK, val);
+ case hwmon_in_enable:
+ *val = test_bit(channel, &st->ch_enable_mask);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+ return 0;
+}
+
+static int ltc4283_read_current_word(const struct ltc4283_hwmon *st, u32 reg,
+ long *val)
+{
+ u64 temp = (u64)LTC4283_ADC1_FS_uV * DECA * MILLI;
+ unsigned int __raw;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &__raw);
+ if (ret)
+ return ret;
+
+ *val = DIV64_U64_ROUND_CLOSEST(__raw * temp,
+ BIT_ULL(16) * st->rsense);
+
+ return 0;
+}
+
+static int ltc4283_read_current_byte(const struct ltc4283_hwmon *st, u32 reg,
+ long *val)
+{
+ u64 temp = (u64)LTC4283_ADC1_FS_uV * DECA * MILLI;
+ u32 curr;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &curr);
+ if (ret)
+ return ret;
+
+ *val = DIV_ROUND_CLOSEST_ULL(curr * temp, BIT(8) * st->rsense);
+ return 0;
+}
+
+static int ltc4283_read_curr(struct ltc4283_hwmon *st, u32 attr, long *val)
+{
+ switch (attr) {
+ case hwmon_curr_input:
+ return ltc4283_read_current_word(st, LTC4283_SENSE, val);
+ case hwmon_curr_highest:
+ return ltc4283_read_current_word(st, LTC4283_SENSE_MAX, val);
+ case hwmon_curr_lowest:
+ return ltc4283_read_current_word(st, LTC4283_SENSE_MIN, val);
+ case hwmon_curr_max:
+ return ltc4283_read_current_byte(st, LTC4283_SENSE_MAX_TH, val);
+ case hwmon_curr_min:
+ return ltc4283_read_current_byte(st, LTC4283_SENSE_MIN_TH, val);
+ case hwmon_curr_max_alarm:
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_1,
+ LTC4283_SENSE_HIGH_ALM, val);
+ case hwmon_curr_min_alarm:
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_1,
+ LTC4283_SENSE_LOW_ALM, val);
+ case hwmon_curr_crit_alarm:
+ return ltc4283_read_alarm(st, LTC4283_FAULT_STATUS,
+ LTC4283_OC_MASK, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_read_power_word(const struct ltc4283_hwmon *st,
+ u32 reg, long *val)
+{
+ u64 temp = (u64)LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV * DECA * MILLI;
+ unsigned int __raw;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &__raw);
+ if (ret)
+ return ret;
+
+ /*
+ * Power is given by:
+ * P = CODE(16b) * 32.768mV * 2.048V / (2^16 * Rsense)
+ */
+ *val = DIV64_U64_ROUND_CLOSEST(temp * __raw, BIT_ULL(16) * st->rsense);
+
+ return 0;
+}
+
+static int ltc4283_read_power_byte(const struct ltc4283_hwmon *st,
+ u32 reg, long *val)
+{
+ u64 temp = (u64)LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV * DECA * MILLI;
+ u32 power;
+ int ret;
+
+ ret = regmap_read(st->map, reg, &power);
+ if (ret)
+ return ret;
+
+ *val = DIV_ROUND_CLOSEST_ULL(power * temp, BIT(8) * st->rsense);
+
+ return 0;
+}
+
+static int ltc4283_read_power(struct ltc4283_hwmon *st, u32 attr, long *val)
+{
+ switch (attr) {
+ case hwmon_power_input:
+ return ltc4283_read_power_word(st, LTC4283_POWER, val);
+ case hwmon_power_input_highest:
+ return ltc4283_read_power_word(st, LTC4283_POWER_MAX, val);
+ case hwmon_power_input_lowest:
+ return ltc4283_read_power_word(st, LTC4283_POWER_MIN, val);
+ case hwmon_power_max_alarm:
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_1,
+ LTC4283_POWER_HIGH_ALM, val);
+ case hwmon_power_min_alarm:
+ return ltc4283_read_alarm(st, LTC4283_ADC_ALM_LOG_1,
+ LTC4283_POWER_LOW_ALM, val);
+ case hwmon_power_max:
+ return ltc4283_read_power_byte(st, LTC4283_POWER_MAX_TH, val);
+ case hwmon_power_min:
+ return ltc4283_read_power_byte(st, LTC4283_POWER_MIN_TH, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_read_energy(struct ltc4283_hwmon *st, u32 attr, s64 *val)
+{
+ u64 temp = LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV, energy, temp_2;
+ u8 raw[8] = {};
+ int ret;
+
+ if (!st->energy_en)
+ return -ENODATA;
+
+ ret = i2c_smbus_read_i2c_block_data(st->client, LTC4283_ENERGY, 6, raw);
+ if (ret < 0)
+ return ret;
+ if (ret != 6)
+ return -EIO;
+
+ energy = get_unaligned_be64(raw) >> 16;
+
+ /*
+ * The formula for energy is given by:
+ * E = CODE(48b) * 32.768mV * 2.048V * Tconv / 2^24 * Rsense
+ *
+ * As Rsense can have tenths of micro-ohm resolution, we need to
+ * multiply by DECA to get microjoule.
+ */
+ if (check_mul_overflow(temp * LTC4283_TCONV_uS, energy, &temp_2)) {
+ /*
+ * We multiply again by 1000 to make sure that we don't get 0
+ * in the following division which could happen for big rsense
+ * values. OTOH, we then divide energy first by 1000 so that
+ * we do not overflow u64 again for very small rsense values.
+ * We add 100 factor for proper conversion to microjoule.
+ */
+ temp_2 = DIV64_U64_ROUND_CLOSEST(temp * LTC4283_TCONV_uS * MILLI,
+ BIT_ULL(24) * st->rsense);
+ energy = DIV_ROUND_CLOSEST_ULL(energy, MILLI * CENTI) * temp_2;
+ } else {
+ /* Put rsense back into nanoohm so we get microjoule. */
+ energy = DIV64_U64_ROUND_CLOSEST(temp_2, BIT_ULL(24) * st->rsense * CENTI);
+ }
+
+ *val = energy;
+ return 0;
+}
+
+static int ltc4283_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct ltc4283_hwmon *st = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_in:
+ return ltc4283_read_in(st, attr, channel, val);
+ case hwmon_curr:
+ return ltc4283_read_curr(st, attr, val);
+ case hwmon_power:
+ return ltc4283_read_power(st, attr, val);
+ case hwmon_energy:
+ *val = st->energy_en;
+ return 0;
+ case hwmon_energy64:
+ return ltc4283_read_energy(st, attr, (s64 *)val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_write_power_byte(const struct ltc4283_hwmon *st, u32 reg,
+ long val)
+{
+ u64 temp = (u64)LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV * DECA * MILLI;
+ u32 __raw;
+
+ val = clamp_val(val, 0, st->power_max);
+ __raw = DIV64_U64_ROUND_CLOSEST(val * BIT_ULL(8) * st->rsense, temp);
+
+ return regmap_write(st->map, reg, __raw);
+}
+
+static int ltc4283_write_power_word(const struct ltc4283_hwmon *st,
+ u32 reg, long val)
+{
+ u64 temp = st->rsense * BIT_ULL(16), temp_2;
+ u16 __raw;
+
+ if (check_mul_overflow(val, temp, &temp_2)) {
+ temp = DIV_ROUND_CLOSEST_ULL(temp, DECA * MILLI);
+ __raw = DIV_ROUND_CLOSEST_ULL(temp * val, LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV);
+ } else {
+ temp = (u64)LTC4283_ADC1_FS_uV * LTC4283_ADC2_FS_mV * DECA * MILLI;
+ __raw = DIV64_U64_ROUND_CLOSEST(temp_2, temp);
+ }
+
+ return regmap_write(st->map, reg, __raw);
+}
+
+static int ltc4283_reset_power_hist(struct ltc4283_hwmon *st)
+{
+ int ret;
+
+ ret = ltc4283_write_power_word(st, LTC4283_POWER_MIN, st->power_max);
+ if (ret)
+ return ret;
+
+ ret = ltc4283_write_power_word(st, LTC4283_POWER_MAX, 0);
+ if (ret)
+ return ret;
+
+ /* Clear possible power faults. */
+ return regmap_clear_bits(st->map, LTC4283_FAULT_LOG,
+ LTC4283_PWR_FAIL_FAULT_MASK | LTC4283_PGI_FAULT_MASK);
+}
+
+static int ltc4283_write_power(struct ltc4283_hwmon *st, u32 attr, long val)
+{
+ switch (attr) {
+ case hwmon_power_max:
+ return ltc4283_write_power_byte(st, LTC4283_POWER_MAX_TH, val);
+ case hwmon_power_min:
+ return ltc4283_write_power_byte(st, LTC4283_POWER_MIN_TH, val);
+ case hwmon_power_reset_history:
+ return ltc4283_reset_power_hist(st);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_write_in_history(struct ltc4283_hwmon *st, u32 reg,
+ long lowest, u32 fs)
+{
+ u32 __raw;
+ int ret;
+
+ __raw = DIV_ROUND_CLOSEST(BIT(16) * lowest, fs);
+ if (__raw == BIT(16))
+ __raw = U16_MAX;
+
+ ret = regmap_write(st->map, reg, __raw);
+ if (ret)
+ return ret;
+
+ return regmap_write(st->map, reg + 1, 0);
+}
+
+static int ltc4283_write_in_byte(const struct ltc4283_hwmon *st,
+ u32 reg, u32 fs, long val)
+{
+ u32 __raw;
+
+ val = clamp_val(val, 0, fs);
+ __raw = DIV_ROUND_CLOSEST(val * BIT(8), fs);
+ if (__raw == BIT(8))
+ __raw = U8_MAX;
+
+ return regmap_write(st->map, reg, __raw);
+}
+
+static int ltc4283_reset_in_hist(struct ltc4283_hwmon *st, u32 channel)
+{
+ u32 reg, fs;
+ int ret;
+
+ /*
+ * Make sure to clear possible under/over voltage faults. Otherwise the
+ * chip won't latch on again.
+ */
+ if (channel == LTC4283_CHAN_VIN)
+ return regmap_clear_bits(st->map, LTC4283_FAULT_LOG,
+ LTC4283_OV_FAULT_MASK | LTC4283_UV_FAULT_MASK);
+
+ if (channel == LTC4283_CHAN_VPWR)
+ return ltc4283_write_in_history(st, LTC4283_VPWR_MIN,
+ LTC4283_ADC2_FS_mV,
+ LTC4283_ADC2_FS_mV);
+
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN) {
+ fs = LTC4283_ADC2_FS_mV;
+ reg = LTC4283_ADC_2_MIN(channel - LTC4283_CHAN_ADI_1);
+ } else {
+ fs = LTC4283_ADC1_FS_uV;
+ reg = LTC4283_ADC_2_MIN_DIFF(channel - LTC4283_CHAN_ADIN12);
+ }
+
+ ret = ltc4283_write_in_history(st, reg, fs, fs);
+ if (ret)
+ return ret;
+ if (channel != LTC4283_CHAN_DRAIN)
+ return 0;
+
+ /* Then, let's also clear possible fet faults. Same as above. */
+ return regmap_clear_bits(st->map, LTC4283_FAULT_LOG,
+ LTC4283_FET_BAD_FAULT_MASK | LTC4283_FET_SHORT_FAULT_MASK);
+}
+
+static int ltc4283_write_in_en(struct ltc4283_hwmon *st, u32 channel, bool en)
+{
+ unsigned int bit, adc_idx = channel - LTC4283_CHAN_ADI_1;
+ unsigned int reg = LTC4283_ADC_SELECT(adc_idx);
+ int ret;
+
+ bit = LTC4283_ADC_SELECT_MASK(adc_idx);
+ if (channel > LTC4283_CHAN_DRAIN)
+ /* Account for two reserved fields after DRAIN. */
+ bit <<= 2;
+
+ if (en)
+ ret = regmap_set_bits(st->map, reg, bit);
+ else
+ ret = regmap_clear_bits(st->map, reg, bit);
+ if (ret)
+ return ret;
+
+ __assign_bit(channel, &st->ch_enable_mask, en);
+ return 0;
+}
+
+static int ltc4283_write_minmax(struct ltc4283_hwmon *st, long val,
+ u32 channel, bool is_max)
+{
+ u32 reg;
+
+ if (channel == LTC4283_CHAN_VPWR) {
+ if (is_max)
+ return ltc4283_write_in_byte(st, LTC4283_VPWR_MAX_TH,
+ LTC4283_ADC2_FS_mV, val);
+
+ return ltc4283_write_in_byte(st, LTC4283_VPWR_MIN_TH,
+ LTC4283_ADC2_FS_mV, val);
+ }
+
+ if (channel >= LTC4283_CHAN_ADI_1 && channel <= LTC4283_CHAN_DRAIN) {
+ if (is_max) {
+ reg = LTC4283_ADC_2_MAX_TH(channel - LTC4283_CHAN_ADI_1);
+ return ltc4283_write_in_byte(st, reg,
+ LTC4283_ADC2_FS_mV, val);
+ }
+
+ reg = LTC4283_ADC_2_MIN_TH(channel - LTC4283_CHAN_ADI_1);
+ return ltc4283_write_in_byte(st, reg, LTC4283_ADC2_FS_mV, val);
+ }
+
+ /* Just sanity check we do not overflow val for 32bit */
+ val = clamp_val(val * MILLI, 0, LTC4283_ADC1_FS_uV);
+
+ if (is_max) {
+ reg = LTC4283_ADC_2_MAX_TH_DIFF(channel - LTC4283_CHAN_ADIN12);
+ return ltc4283_write_in_byte(st, reg, LTC4283_ADC1_FS_uV, val);
+ }
+
+ reg = LTC4283_ADC_2_MIN_TH_DIFF(channel - LTC4283_CHAN_ADIN12);
+ return ltc4283_write_in_byte(st, reg, LTC4283_ADC1_FS_uV, val);
+}
+
+static int ltc4283_write_in(struct ltc4283_hwmon *st, u32 attr, long val,
+ int channel)
+{
+ switch (attr) {
+ case hwmon_in_max:
+ return ltc4283_write_minmax(st, val, channel, true);
+ case hwmon_in_min:
+ return ltc4283_write_minmax(st, val, channel, false);
+ case hwmon_in_reset_history:
+ return ltc4283_reset_in_hist(st, channel);
+ case hwmon_in_enable:
+ return ltc4283_write_in_en(st, channel, !!val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_write_curr_byte(const struct ltc4283_hwmon *st,
+ u32 reg, long val)
+{
+ u32 temp = LTC4283_ADC1_FS_uV * DECA * MILLI;
+ u32 reg_val, isense_max;
+
+ isense_max = DIV_ROUND_CLOSEST(st->vsense_max * MICRO * DECA, st->rsense);
+ val = clamp_val(val, 0, isense_max);
+ reg_val = DIV_ROUND_CLOSEST_ULL(val * BIT_ULL(8) * st->rsense, temp);
+
+ return regmap_write(st->map, reg, reg_val);
+}
+
+static int ltc4283_write_curr_history(struct ltc4283_hwmon *st)
+{
+ int ret;
+
+ ret = ltc4283_write_in_history(st, LTC4283_SENSE_MIN,
+ st->vsense_max * MILLI,
+ LTC4283_ADC1_FS_uV);
+ if (ret)
+ return ret;
+
+ /* Now, let's also clear possible overcurrent logs. */
+ return regmap_clear_bits(st->map, LTC4283_FAULT_LOG,
+ LTC4283_OC_FAULT_MASK);
+}
+
+static int ltc4283_write_curr(struct ltc4283_hwmon *st, u32 attr, long val)
+{
+ switch (attr) {
+ case hwmon_curr_max:
+ return ltc4283_write_curr_byte(st, LTC4283_SENSE_MAX_TH, val);
+ case hwmon_curr_min:
+ return ltc4283_write_curr_byte(st, LTC4283_SENSE_MIN_TH, val);
+ case hwmon_curr_reset_history:
+ return ltc4283_write_curr_history(st);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4283_energy_enable_set(struct ltc4283_hwmon *st, long val)
+{
+ int ret;
+
+ /* Setting the bit halts the meter. */
+ val = !!val;
+ ret = regmap_update_bits(st->map, LTC4283_METER_CONTROL,
+ LTC4283_METER_HALT_MASK,
+ FIELD_PREP(LTC4283_METER_HALT_MASK, !val));
+ if (ret)
+ return ret;
+
+ st->energy_en = val;
+
+ return 0;
+}
+
+static int ltc4283_write(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long val)
+{
+ struct ltc4283_hwmon *st = dev_get_drvdata(dev);
+
+ switch (type) {
+ case hwmon_power:
+ return ltc4283_write_power(st, attr, val);
+ case hwmon_in:
+ return ltc4283_write_in(st, attr, val, channel);
+ case hwmon_curr:
+ return ltc4283_write_curr(st, attr, val);
+ case hwmon_energy:
+ return ltc4283_energy_enable_set(st, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t ltc4283_in_is_visible(const struct ltc4283_hwmon *st,
+ u32 attr, int channel)
+{
+ /* If ADIO is set as a GPIO, don´t make it visible. */
+ if (channel >= LTC4283_CHAN_ADIO_1 && channel <= LTC4283_CHAN_ADIO_4) {
+ /* ADIOX pins come at index 0 in the gpio mask. */
+ channel -= LTC4283_CHAN_ADIO_1;
+ if (test_bit(channel, &st->gpio_mask))
+ return 0;
+ }
+
+ /* Also take care of differential channels. */
+ if (channel >= LTC4283_CHAN_ADIO12 && channel <= LTC4283_CHAN_ADIO34) {
+ channel -= LTC4283_CHAN_ADIO12;
+ /* If one channel in the pair is used, make it invisible. */
+ if (test_bit(channel * 2, &st->gpio_mask) ||
+ test_bit(channel * 2 + 1, &st->gpio_mask))
+ return 0;
+ }
+
+ switch (attr) {
+ case hwmon_in_input:
+ case hwmon_in_highest:
+ case hwmon_in_lowest:
+ case hwmon_in_max_alarm:
+ case hwmon_in_min_alarm:
+ case hwmon_in_label:
+ case hwmon_in_lcrit_alarm:
+ case hwmon_in_crit_alarm:
+ case hwmon_in_fault:
+ return 0444;
+ case hwmon_in_max:
+ case hwmon_in_min:
+ case hwmon_in_enable:
+ return 0644;
+ case hwmon_in_reset_history:
+ return 0200;
+ default:
+ return 0;
+ }
+}
+
+static umode_t ltc4283_curr_is_visible(u32 attr)
+{
+ switch (attr) {
+ case hwmon_curr_input:
+ case hwmon_curr_highest:
+ case hwmon_curr_lowest:
+ case hwmon_curr_max_alarm:
+ case hwmon_curr_min_alarm:
+ case hwmon_curr_crit_alarm:
+ case hwmon_curr_label:
+ return 0444;
+ case hwmon_curr_max:
+ case hwmon_curr_min:
+ return 0644;
+ case hwmon_curr_reset_history:
+ return 0200;
+ default:
+ return 0;
+ }
+}
+
+static umode_t ltc4283_power_is_visible(u32 attr)
+{
+ switch (attr) {
+ case hwmon_power_input:
+ case hwmon_power_input_highest:
+ case hwmon_power_input_lowest:
+ case hwmon_power_label:
+ case hwmon_power_max_alarm:
+ case hwmon_power_min_alarm:
+ return 0444;
+ case hwmon_power_max:
+ case hwmon_power_min:
+ return 0644;
+ case hwmon_power_reset_history:
+ return 0200;
+ default:
+ return 0;
+ }
+}
+
+static umode_t ltc4283_is_visible(const void *data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ switch (type) {
+ case hwmon_in:
+ return ltc4283_in_is_visible(data, attr, channel);
+ case hwmon_curr:
+ return ltc4283_curr_is_visible(attr);
+ case hwmon_power:
+ return ltc4283_power_is_visible(attr);
+ case hwmon_energy:
+ /* hwmon_energy_enable */
+ return 0644;
+ case hwmon_energy64:
+ /* hwmon_energy_input */
+ return 0444;
+ default:
+ return 0;
+ }
+}
+
+static const char * const ltc4283_in_strs[] = {
+ "VIN", "VPWR", "VADI1", "VADI2", "VADI3", "VADI4", "VADIO1", "VADIO2",
+ "VADIO3", "VADIO4", "DRNS", "DRAIN", "ADIN2-ADIN1", "ADIN4-ADIN3",
+ "ADIO2-ADIO1", "ADIO4-ADIO3"
+};
+
+static int ltc4283_read_labels(struct device *dev,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel, const char **str)
+{
+ switch (type) {
+ case hwmon_in:
+ *str = ltc4283_in_strs[channel];
+ return 0;
+ case hwmon_curr:
+ *str = "ISENSE";
+ return 0;
+ case hwmon_power:
+ *str = "Power";
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+/*
+ * Set max limits for ISENSE and Power as that depends on the max voltage on
+ * rsense that is defined in ILIM_ADJUST. This is specially important for power
+ * because for some rsense and vfsout values, if we allow the default raw 255
+ * value, that would overflow long in 32bit archs when reading back the max
+ * power limit.
+ */
+static int ltc4283_set_max_limits(struct ltc4283_hwmon *st, struct device *dev)
+{
+ u32 temp = st->vsense_max * DECA * MICRO;
+ int ret;
+
+ ret = ltc4283_write_in_byte(st, LTC4283_SENSE_MAX_TH, LTC4283_ADC1_FS_uV,
+ st->vsense_max * MILLI);
+ if (ret)
+ return ret;
+
+ /* Power is given by ISENSE * Vout. */
+ st->power_max = DIV_ROUND_CLOSEST(temp, st->rsense) * LTC4283_ADC2_FS_mV;
+ return ltc4283_write_power_byte(st, LTC4283_POWER_MAX_TH, st->power_max);
+}
+
+static int ltc4283_parse_array_prop(const struct ltc4283_hwmon *st,
+ struct device *dev, const char *prop,
+ const u32 *vals, u32 n_vals)
+{
+ u32 prop_val;
+ int ret;
+ u32 i;
+
+ ret = device_property_read_u32(dev, prop, &prop_val);
+ if (ret)
+ return n_vals;
+
+ for (i = 0; i < n_vals; i++) {
+ if (prop_val != vals[i])
+ continue;
+
+ return i;
+ }
+
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid %s property value %u, expected one of: %*ph\n",
+ prop, prop_val, n_vals, vals);
+}
+
+static int ltc4283_get_defaults(struct ltc4283_hwmon *st)
+{
+ u32 reg_val, ilm_adjust, c;
+ int ret;
+
+ ret = regmap_read(st->map, LTC4283_METER_CONTROL, ®_val);
+ if (ret)
+ return ret;
+
+ st->energy_en = !FIELD_GET(LTC4283_METER_HALT_MASK, reg_val);
+
+ ret = regmap_read(st->map, LTC4283_CONFIG_1, ®_val);
+ if (ret)
+ return ret;
+
+ ilm_adjust = FIELD_GET(LTC4283_ILIM_MASK, reg_val);
+ st->vsense_max = LTC4283_VILIM_MIN_uV / MILLI + ilm_adjust;
+
+ ret = regmap_read(st->map, LTC4283_PGIO_CONFIG, ®_val);
+ if (ret)
+ return ret;
+
+ /* Can be latter overwritten in ltc4283_pgio_config() */
+ if (FIELD_GET(LTC4283_PGIO4_CFG_MASK, reg_val) < LTC4283_PGIO_FUNC_GPIO)
+ st->ext_fault = true;
+
+ /* VPWR and VIN are always enabled */
+ __set_bit(LTC4283_CHAN_VIN, &st->ch_enable_mask);
+ __set_bit(LTC4283_CHAN_VPWR, &st->ch_enable_mask);
+ for (c = LTC4283_CHAN_ADI_1; c < LTC4283_CHAN_MAX; c++) {
+ u32 chan = c - LTC4283_CHAN_ADI_1, bit;
+
+ ret = regmap_read(st->map, LTC4283_ADC_SELECT(chan), ®_val);
+ if (ret)
+ return ret;
+
+ bit = LTC4283_ADC_SELECT_MASK(chan);
+ if (c > LTC4283_CHAN_DRAIN)
+ /* account for two reserved fields after DRAIN */
+ bit <<= 2;
+
+ if (!(bit & reg_val))
+ continue;
+
+ __set_bit(c, &st->ch_enable_mask);
+ }
+
+ return 0;
+}
+
+static const char * const ltc4283_pgio1_funcs[] = {
+ "inverted_power_good", "power_good", "gpio"
+};
+
+static const char * const ltc4283_pgio2_funcs[] = {
+ "inverted_power_good", "power_good", "gpio", "active_current_limiting"
+};
+
+static const char * const ltc4283_pgio3_funcs[] = {
+ "inverted_power_good_input", "power_good_input", "gpio"
+};
+
+static const char * const ltc4283_pgio4_funcs[] = {
+ "inverted_external_fault", "external_fault", "gpio"
+};
+
+enum {
+ LTC4283_PIN_ADIO1,
+ LTC4283_PIN_ADIO2,
+ LTC4283_PIN_ADIO3,
+ LTC4283_PIN_ADIO4,
+ LTC4283_PIN_PGIO1,
+ LTC4283_PIN_PGIO2,
+ LTC4283_PIN_PGIO3,
+ LTC4283_PIN_PGIO4,
+};
+
+static int ltc4283_pgio_config(struct ltc4283_hwmon *st, struct device *dev)
+{
+ int ret, func;
+
+ func = device_property_match_property_string(dev, "adi,pgio1-func",
+ ltc4283_pgio1_funcs,
+ ARRAY_SIZE(ltc4283_pgio1_funcs));
+ if (func < 0 && func != -EINVAL)
+ return dev_err_probe(dev, func,
+ "Invalid adi,pgio1-func property\n");
+ if (func >= 0) {
+ if (func == LTC4283_PGIO_FUNC_GPIO) {
+ __set_bit(LTC4283_PIN_PGIO1, &st->gpio_mask);
+ /* If GPIO, default to an input pin. */
+ func++;
+ }
+
+ ret = regmap_update_bits(st->map, LTC4283_PGIO_CONFIG,
+ LTC4283_PGIO1_CFG_MASK,
+ FIELD_PREP(LTC4283_PGIO1_CFG_MASK, func));
+ if (ret)
+ return ret;
+ }
+
+ func = device_property_match_property_string(dev, "adi,pgio2-func",
+ ltc4283_pgio2_funcs,
+ ARRAY_SIZE(ltc4283_pgio2_funcs));
+
+ if (func < 0 && func != -EINVAL)
+ return dev_err_probe(dev, func,
+ "Invalid adi,pgio2-func property\n");
+ if (func >= 0) {
+ if (func != LTC4283_PGIO2_FUNC_ACLB) {
+ if (func == LTC4283_PGIO_FUNC_GPIO) {
+ __set_bit(LTC4283_PIN_PGIO2, &st->gpio_mask);
+ func++;
+ }
+
+ ret = regmap_update_bits(st->map, LTC4283_PGIO_CONFIG,
+ LTC4283_PGIO2_CFG_MASK,
+ FIELD_PREP(LTC4283_PGIO2_CFG_MASK, func));
+ } else {
+ ret = regmap_set_bits(st->map, LTC4283_CONTROL_1,
+ LTC4283_PIGIO2_ACLB_MASK);
+ }
+
+ if (ret)
+ return ret;
+ }
+
+ func = device_property_match_property_string(dev, "adi,pgio3-func",
+ ltc4283_pgio3_funcs,
+ ARRAY_SIZE(ltc4283_pgio3_funcs));
+
+ if (func < 0 && func != -EINVAL)
+ return dev_err_probe(dev, func,
+ "Invalid adi,pgio3-func property\n");
+ if (func >= 0) {
+ if (func == LTC4283_PGIO_FUNC_GPIO) {
+ __set_bit(LTC4283_PIN_PGIO3, &st->gpio_mask);
+ func++;
+ }
+
+ ret = regmap_update_bits(st->map, LTC4283_PGIO_CONFIG,
+ LTC4283_PGIO3_CFG_MASK,
+ FIELD_PREP(LTC4283_PGIO3_CFG_MASK, func));
+ if (ret)
+ return ret;
+ }
+
+ func = device_property_match_property_string(dev, "adi,pgio4-func",
+ ltc4283_pgio4_funcs,
+ ARRAY_SIZE(ltc4283_pgio4_funcs));
+
+ if (func < 0 && func != -EINVAL)
+ return dev_err_probe(dev, func,
+ "Invalid adi,pgio4-func property\n");
+ if (func >= 0) {
+ if (func == LTC4283_PGIO_FUNC_GPIO) {
+ __set_bit(LTC4283_PIN_PGIO4, &st->gpio_mask);
+ func++;
+ st->ext_fault = false;
+ } else {
+ st->ext_fault = true;
+ }
+
+ ret = regmap_update_bits(st->map, LTC4283_PGIO_CONFIG,
+ LTC4283_PGIO4_CFG_MASK,
+ FIELD_PREP(LTC4283_PGIO4_CFG_MASK, func));
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int ltc4283_adio_config(struct ltc4283_hwmon *st, struct device *dev,
+ const char *prop, u32 pin)
+{
+ u32 adc_idx;
+ int ret;
+
+ if (!device_property_read_bool(dev, prop))
+ return 0;
+
+ adc_idx = LTC4283_CHAN_ADIO_1 - LTC4283_CHAN_ADI_1 + pin;
+ ret = regmap_clear_bits(st->map, LTC4283_ADC_SELECT(adc_idx),
+ LTC4283_ADC_SELECT_MASK(adc_idx));
+ if (ret)
+ return ret;
+
+ __set_bit(pin, &st->gpio_mask);
+ return 0;
+}
+
+static int ltc4283_pin_config(struct ltc4283_hwmon *st, struct device *dev)
+{
+ int ret;
+
+ ret = ltc4283_pgio_config(st, dev);
+ if (ret)
+ return ret;
+
+ ret = ltc4283_adio_config(st, dev, "adi,gpio-on-adio1", LTC4283_PIN_ADIO1);
+ if (ret)
+ return ret;
+
+ ret = ltc4283_adio_config(st, dev, "adi,gpio-on-adio2", LTC4283_PIN_ADIO2);
+ if (ret)
+ return ret;
+
+ ret = ltc4283_adio_config(st, dev, "adi,gpio-on-adio3", LTC4283_PIN_ADIO3);
+ if (ret)
+ return ret;
+
+ return ltc4283_adio_config(st, dev, "adi,gpio-on-adio4", LTC4283_PIN_ADIO4);
+}
+
+static const char * const ltc4283_oc_fet_retry[] = {
+ "latch-off", "1", "7", "unlimited"
+};
+
+static const u32 ltc4283_fb_factor[] = {
+ 100, 50, 20, 10
+};
+
+static const u32 ltc4283_cooling_dl[] = {
+ 512, 1002, 2005, 4100, 8190, 16400, 32800, 65600
+};
+
+static const u32 ltc4283_fet_bad_delay[] = {
+ 256, 512, 1002, 2005
+};
+
+static int ltc4283_setup(struct ltc4283_hwmon *st, struct device *dev)
+{
+ u32 val;
+ int ret;
+
+ /* The part has an eeprom so let's get the needed defaults from it */
+ ret = ltc4283_get_defaults(st);
+ if (ret)
+ return ret;
+
+ /*
+ * Default to LTC4283_MIN_RSENSE so we can probe without FW properties.
+ */
+ st->rsense = LTC4283_MIN_RSENSE;
+ ret = device_property_read_u32(dev, "adi,rsense-nano-ohms",
+ &st->rsense);
+ if (!ret) {
+ if (st->rsense < LTC4283_MIN_RSENSE || st->rsense > LTC4283_MAX_RSENSE)
+ return dev_err_probe(dev, -EINVAL,
+ "adi,rsense-nano-ohms(%u) too small or too large [%u %u]\n",
+ st->rsense, LTC4283_MIN_RSENSE, LTC4283_MAX_RSENSE);
+ }
+
+ /*
+ * The resolution for rsense is tenths of micro (eg: 62.5 uOhm) which
+ * means we need nano in the bindings. However, to make things easier to
+ * handle (with respect to overflows) we divide it by 100 as we don't
+ * really need the last two digits.
+ */
+ st->rsense /= CENTI;
+
+ ret = device_property_read_u32(dev, "adi,current-limit-sense-microvolt",
+ &st->vsense_max);
+ if (!ret) {
+ u32 reg_val;
+
+ if (!in_range(st->vsense_max, LTC4283_VILIM_MIN_uV,
+ LTC4283_VILIM_RANGE)) {
+ return dev_err_probe(dev, -EINVAL,
+ "adi,current-limit-sense-microvolt (%u) out of range [%u %u]\n",
+ st->vsense_max, LTC4283_VILIM_MIN_uV,
+ LTC4283_VILIM_MAX_uV);
+ }
+
+ st->vsense_max /= MILLI;
+ reg_val = FIELD_PREP(LTC4283_ILIM_MASK,
+ st->vsense_max - LTC4283_VILIM_MIN_uV / MILLI);
+ ret = regmap_update_bits(st->map, LTC4283_CONFIG_1,
+ LTC4283_ILIM_MASK, reg_val);
+ if (ret)
+ return ret;
+ }
+
+ ret = ltc4283_parse_array_prop(st, dev, "adi,current-limit-foldback-factor",
+ ltc4283_fb_factor, ARRAY_SIZE(ltc4283_fb_factor));
+ if (ret < 0)
+ return ret;
+ if (ret < ARRAY_SIZE(ltc4283_fb_factor)) {
+ ret = regmap_update_bits(st->map, LTC4283_CONFIG_1, LTC4283_FB_MASK,
+ FIELD_PREP(LTC4283_FB_MASK, ret));
+ if (ret)
+ return ret;
+ }
+
+ ret = ltc4283_parse_array_prop(st, dev, "adi,cooling-delay-ms",
+ ltc4283_cooling_dl, ARRAY_SIZE(ltc4283_cooling_dl));
+ if (ret < 0)
+ return ret;
+ if (ret < ARRAY_SIZE(ltc4283_cooling_dl)) {
+ ret = regmap_update_bits(st->map, LTC4283_CONFIG_2, LTC4283_COOLING_DL_MASK,
+ FIELD_PREP(LTC4283_COOLING_DL_MASK, ret));
+ if (ret)
+ return ret;
+ }
+
+ ret = ltc4283_parse_array_prop(st, dev, "adi,fet-bad-timer-delay-ms",
+ ltc4283_fet_bad_delay, ARRAY_SIZE(ltc4283_fet_bad_delay));
+ if (ret < 0)
+ return ret;
+ if (ret < ARRAY_SIZE(ltc4283_fet_bad_delay)) {
+ ret = regmap_update_bits(st->map, LTC4283_CONFIG_2, LTC4283_FTBD_DL_MASK,
+ FIELD_PREP(LTC4283_FTBD_DL_MASK, ret));
+ if (ret)
+ return ret;
+ }
+
+ ret = ltc4283_set_max_limits(st, dev);
+ if (ret)
+ return ret;
+
+ ret = ltc4283_pin_config(st, dev);
+ if (ret)
+ return ret;
+
+ if (device_property_read_bool(dev, "adi,power-good-reset-on-fet")) {
+ ret = regmap_clear_bits(st->map, LTC4283_CONTROL_1,
+ LTC4283_PWRGD_RST_CTRL_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,fet-turn-off-disable")) {
+ ret = regmap_clear_bits(st->map, LTC4283_CONTROL_1,
+ LTC4283_FET_BAD_OFF_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,tmr-pull-down-disable")) {
+ ret = regmap_set_bits(st->map, LTC4283_CONTROL_1,
+ LTC4283_THERM_TMR_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,dvdt-inrush-control-disable")) {
+ ret = regmap_clear_bits(st->map, LTC4283_CONTROL_1,
+ LTC4283_DVDT_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,undervoltage-retry-disable")) {
+ ret = regmap_clear_bits(st->map, LTC4283_CONTROL_2,
+ LTC4283_UV_RETRY_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,overvoltage-retry-disable")) {
+ ret = regmap_clear_bits(st->map, LTC4283_CONTROL_2,
+ LTC4283_OV_RETRY_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,external-fault-retry-enable")) {
+ if (!st->ext_fault)
+ return dev_err_probe(dev, -EINVAL,
+ "adi,external-fault-retry-enable set but PGIO4 not configured\n");
+ ret = regmap_set_bits(st->map, LTC4283_CONTROL_2,
+ LTC4283_EXT_FAULT_RETRY_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,fault-log-enable")) {
+ ret = regmap_set_bits(st->map, LTC4283_FAULT_LOG_CTRL,
+ LTC4283_FAULT_LOG_EN_MASK);
+ if (ret)
+ return ret;
+ }
+
+ ret = device_property_match_property_string(dev, "adi,overcurrent-retries",
+ ltc4283_oc_fet_retry,
+ ARRAY_SIZE(ltc4283_oc_fet_retry));
+ /* We still want to catch when an invalid string is given. */
+ if (ret < 0 && ret != -EINVAL)
+ return dev_err_probe(dev, ret,
+ "adi,overcurrent-retries invalid value\n");
+ if (ret >= 0) {
+ ret = regmap_update_bits(st->map, LTC4283_CONTROL_2,
+ LTC4283_OC_RETRY_MASK,
+ FIELD_PREP(LTC4283_OC_RETRY_MASK, ret));
+ if (ret)
+ return ret;
+ }
+
+ ret = device_property_match_property_string(dev, "adi,fet-bad-retries",
+ ltc4283_oc_fet_retry,
+ ARRAY_SIZE(ltc4283_oc_fet_retry));
+ if (ret < 0 && ret != -EINVAL)
+ return dev_err_probe(dev, ret,
+ "adi,fet-bad-retries invalid value\n");
+ if (ret >= 0) {
+ ret = regmap_update_bits(st->map, LTC4283_CONTROL_2,
+ LTC4283_FET_BAD_RETRY_MASK,
+ FIELD_PREP(LTC4283_FET_BAD_RETRY_MASK, ret));
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,external-fault-fet-off-enable")) {
+ if (!st->ext_fault)
+ return dev_err_probe(dev, -EINVAL,
+ "adi,external-fault-fet-off-enable set but PGIO4 not configured\n");
+ ret = regmap_set_bits(st->map, LTC4283_CONFIG_3,
+ LTC4283_EXTFLT_TURN_OFF_MASK);
+ if (ret)
+ return ret;
+ }
+
+ if (device_property_read_bool(dev, "adi,vpower-drns-enable")) {
+ u32 chan = LTC4283_CHAN_DRNS - LTC4283_CHAN_ADI_1;
+
+ __clear_bit(LTC4283_CHAN_DRNS, &st->ch_enable_mask);
+ /*
+ * Then, let's by default disable DRNS from ADC2 given that it
+ * is already being monitored by the VPWR channel. One can still
+ * enable it later on if needed.
+ */
+ ret = regmap_clear_bits(st->map, LTC4283_ADC_SELECT(chan),
+ LTC4283_ADC_SELECT_MASK(chan));
+ if (ret)
+ return ret;
+
+ val = 1;
+ } else {
+ val = 0;
+ }
+
+ ret = regmap_update_bits(st->map, LTC4283_CONFIG_3,
+ LTC4283_VPWR_DRNS_MASK,
+ FIELD_PREP(LTC4283_VPWR_DRNS_MASK, val));
+ if (ret)
+ return ret;
+
+ /* Make sure the ADC has 12bit resolution since we're assuming that. */
+ ret = regmap_update_bits(st->map, LTC4283_PGIO_CONFIG_2,
+ LTC4283_ADC_MASK,
+ FIELD_PREP(LTC4283_ADC_MASK, 3));
+ if (ret)
+ return ret;
+
+ /* Energy reads (which are 6 byte block reads) rely on page access */
+ ret = regmap_set_bits(st->map, LTC4283_CONTROL_1, LTC4283_RW_PAGE_MASK);
+ if (ret)
+ return ret;
+
+ /*
+ * Make sure we are integrating power as we only support reporting
+ * consumed energy.
+ */
+ return regmap_clear_bits(st->map, LTC4283_METER_CONTROL,
+ LTC4283_INTEGRATE_I_MASK);
+}
+
+static const struct hwmon_channel_info * const ltc4283_info[] = {
+ HWMON_CHANNEL_INFO(in,
+ HWMON_I_LCRIT_ALARM | HWMON_I_CRIT_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_MAX_ALARM | HWMON_I_RESET_HISTORY |
+ HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_FAULT | HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL,
+ HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST |
+ HWMON_I_MAX | HWMON_I_MIN | HWMON_I_MIN_ALARM |
+ HWMON_I_RESET_HISTORY | HWMON_I_MAX_ALARM |
+ HWMON_I_ENABLE | HWMON_I_LABEL),
+ HWMON_CHANNEL_INFO(curr,
+ HWMON_C_INPUT | HWMON_C_LOWEST | HWMON_C_HIGHEST |
+ HWMON_C_MAX | HWMON_C_MIN | HWMON_C_MIN_ALARM |
+ HWMON_C_MAX_ALARM | HWMON_C_CRIT_ALARM |
+ HWMON_C_RESET_HISTORY | HWMON_C_LABEL),
+ HWMON_CHANNEL_INFO(power,
+ HWMON_P_INPUT | HWMON_P_INPUT_LOWEST |
+ HWMON_P_INPUT_HIGHEST | HWMON_P_MAX | HWMON_P_MIN |
+ HWMON_P_MAX_ALARM | HWMON_P_MIN_ALARM |
+ HWMON_P_RESET_HISTORY | HWMON_P_LABEL),
+ HWMON_CHANNEL_INFO(energy,
+ HWMON_E_ENABLE),
+ HWMON_CHANNEL_INFO(energy64,
+ HWMON_E_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops ltc4283_ops = {
+ .read = ltc4283_read,
+ .write = ltc4283_write,
+ .is_visible = ltc4283_is_visible,
+ .read_string = ltc4283_read_labels,
+};
+
+static const struct hwmon_chip_info ltc4283_chip_info = {
+ .ops = <c4283_ops,
+ .info = ltc4283_info,
+};
+
+static int ltc4283_show_fault_log(void *arg, u64 *val, u32 mask)
+{
+ struct ltc4283_hwmon *st = arg;
+ long alarm;
+ int ret;
+
+ ret = ltc4283_read_alarm(st, LTC4283_FAULT_LOG, mask, &alarm);
+ if (ret)
+ return ret;
+
+ *val = alarm;
+
+ return 0;
+}
+
+static int ltc4283_show_in0_lcrit_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_UV_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_in0_lcrit_fault_log,
+ ltc4283_show_in0_lcrit_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_in0_crit_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_OV_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_in0_crit_fault_log,
+ ltc4283_show_in0_crit_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_fet_bad_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_FET_BAD_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_fet_bad_fault_log,
+ ltc4283_show_fet_bad_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_fet_short_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_FET_SHORT_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_fet_short_fault_log,
+ ltc4283_show_fet_short_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_curr1_crit_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_OC_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_curr1_crit_fault_log,
+ ltc4283_show_curr1_crit_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_power1_failed_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_PWR_FAIL_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_power1_failed_fault_log,
+ ltc4283_show_power1_failed_fault_log, NULL, "%llu\n");
+
+static int ltc4283_show_power1_good_input_fault_log(void *arg, u64 *val)
+{
+ return ltc4283_show_fault_log(arg, val, LTC4283_PGI_FAULT_MASK);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ltc4283_power1_good_input_fault_log,
+ ltc4283_show_power1_good_input_fault_log, NULL, "%llu\n");
+
+static void ltc4283_debugfs_init(struct ltc4283_hwmon *st, struct i2c_client *i2c)
+{
+ debugfs_create_file_unsafe("in0_crit_fault_log", 0400, i2c->debugfs, st,
+ <c4283_in0_crit_fault_log);
+ debugfs_create_file_unsafe("in0_lcrit_fault_log", 0400, i2c->debugfs, st,
+ <c4283_in0_lcrit_fault_log);
+ debugfs_create_file_unsafe("in0_fet_bad_fault_log", 0400, i2c->debugfs, st,
+ <c4283_fet_bad_fault_log);
+ debugfs_create_file_unsafe("in0_fet_short_fault_log", 0400, i2c->debugfs, st,
+ <c4283_fet_short_fault_log);
+ debugfs_create_file_unsafe("curr1_crit_fault_log", 0400, i2c->debugfs, st,
+ <c4283_curr1_crit_fault_log);
+ debugfs_create_file_unsafe("power1_failed_fault_log", 0400, i2c->debugfs, st,
+ <c4283_power1_failed_fault_log);
+ debugfs_create_file_unsafe("power1_good_input_fault_log", 0400, i2c->debugfs,
+ st, <c4283_power1_good_input_fault_log);
+}
+
+static bool ltc4283_is_word_reg(unsigned int reg)
+{
+ return reg >= LTC4283_SENSE && reg <= LTC4283_ADIO34_MAX;
+}
+
+static int ltc4283_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+ struct i2c_client *client = context;
+ int ret;
+
+ if (ltc4283_is_word_reg(reg))
+ ret = i2c_smbus_read_word_swapped(client, reg);
+ else
+ ret = i2c_smbus_read_byte_data(client, reg);
+
+ if (ret < 0)
+ return ret;
+
+ *val = ret;
+ return 0;
+}
+
+static int ltc4283_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+ struct i2c_client *client = context;
+
+ if (ltc4283_is_word_reg(reg))
+ return i2c_smbus_write_word_swapped(client, reg, val);
+
+ return i2c_smbus_write_byte_data(client, reg, val);
+}
+
+static const struct regmap_bus ltc4283_regmap_bus = {
+ .reg_read = ltc4283_reg_read,
+ .reg_write = ltc4283_reg_write,
+};
+
+static bool ltc4283_writable_reg(struct device *dev, unsigned int reg)
+{
+ switch (reg) {
+ case LTC4283_SYSTEM_STATUS ... LTC4283_FAULT_STATUS:
+ return false;
+ case LTC4283_RESERVED_OC:
+ return false;
+ case LTC4283_RESERVED_86 ... LTC4283_RESERVED_8F:
+ return false;
+ case LTC4283_RESERVED_91 ... LTC4283_RESERVED_A1:
+ return false;
+ case LTC4283_RESERVED_A3:
+ return false;
+ case LTC4283_RESERVED_AC:
+ return false;
+ case LTC4283_POWER_PLAY_MSB ... LTC4283_POWER_PLAY_LSB:
+ return false;
+ case LTC4283_RESERVED_F1 ... LTC4283_RESERVED_FF:
+ return false;
+ default:
+ return true;
+ }
+}
+
+static const struct regmap_config ltc4283_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+ .max_register = 0xFF,
+ .writeable_reg = ltc4283_writable_reg,
+};
+
+static int ltc4283_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev, *hwmon;
+ struct auxiliary_device *adev;
+ struct ltc4283_hwmon *st;
+ int ret, id;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA |
+ I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return -EOPNOTSUPP;
+
+ st->client = client;
+ st->map = devm_regmap_init(dev, <c4283_regmap_bus, client,
+ <c4283_regmap_config);
+ if (IS_ERR(st->map))
+ return dev_err_probe(dev, PTR_ERR(st->map),
+ "Failed to create regmap\n");
+
+ ret = ltc4283_setup(st, dev);
+ if (ret)
+ return ret;
+
+ hwmon = devm_hwmon_device_register_with_info(dev, "ltc4283", st,
+ <c4283_chip_info, NULL);
+
+ if (IS_ERR(hwmon))
+ return PTR_ERR(hwmon);
+
+ ltc4283_debugfs_init(st, client);
+
+ if (!st->gpio_mask)
+ return 0;
+
+ id = (client->adapter->nr << 10) | client->addr;
+ adev = __devm_auxiliary_device_create(dev, KBUILD_MODNAME, "gpio",
+ NULL, id);
+ if (!adev)
+ return dev_err_probe(dev, -ENODEV, "Failed to add GPIO device\n");
+
+ return 0;
+}
+
+static const struct of_device_id ltc4283_of_match[] = {
+ { .compatible = "adi,ltc4283" },
+ { }
+};
+
+static const struct i2c_device_id ltc4283_i2c_id[] = {
+ { "ltc4283" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4283_i2c_id);
+
+static struct i2c_driver ltc4283_driver = {
+ .driver = {
+ .name = "ltc4283",
+ .of_match_table = ltc4283_of_match,
+ },
+ .probe = ltc4283_probe,
+ .id_table = ltc4283_i2c_id,
+};
+module_i2c_driver(ltc4283_driver);
+
+MODULE_AUTHOR("Nuno Sá <nuno.sa@analog.com>");
+MODULE_DESCRIPTION("LTC4283 Hot Swap Controller driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 0/3] hwmon: Add support for the LTC4283 Hot Swap Controller
From: Nuno Sá via B4 Relay @ 2026-04-06 14:31 UTC (permalink / raw)
To: linux-gpio, linux-hwmon, devicetree, linux-doc
Cc: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Linus Walleij, Bartosz Golaszewski,
Bartosz Golaszewski
This is v8 for the LTC4283 how swap controller.
Similar to the LTC4282 device, we're clearing some fault logs in the
reset_history attributes.
Guenter, for my last email worrying about rsense low values, this is
what I got internally:
"10uOhm at the smallest sense voltage of 15mV would be 1500A and 72kW, which
seems a tad excessive. The highest currents I’ve seen are around 200A, and
the -48V market 4283 serves is generally a lot lower than that. Normal values
are around 200uOhm. I’d say the resolution should be around 1uohm and if a
minimum is needed, 50uOhm is probably safe."
For the resolution, I'm pretty sure I got the tenths of micro
resolution for ltc4282 so I just kept it in here. So, if you don't mind
I would prefer to keep it this way to be safer and changing that now would
require me to change some formulas and I would prefer not to do that at
this stage.
---
Changes in v9:
- Patch 2:
* Add max and min rsense values to avoid 32bit overflows in power and
rsense * 256;
* Fix typo in ltc4283_read_in_alarm() s/LTC4283_CHAN_ADIN34/LTC4283_CHAN_ADIO34;
* Clamp 'val * MILLI' for LTC4283_ADC1_FS_uV in ltc4283_read_in_alarm();
* Adapt rsense default and property reading for the new range values.
* Properly construct an auxdev id from the i2c client.
- Link to v8: https://patch.msgid.link/20260327-ltc4283-support-v8-0-471de255d728@analog.com
---
---
Nuno Sá (3):
dt-bindings: hwmon: Document the LTC4283 Swap Controller
hwmon: ltc4283: Add support for the LTC4283 Swap Controller
gpio: gpio-ltc4283: Add support for the LTC4283 Swap Controller
.../devicetree/bindings/hwmon/adi,ltc4283.yaml | 272 +++
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/ltc4283.rst | 266 +++
MAINTAINERS | 9 +
drivers/gpio/Kconfig | 15 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-ltc4283.c | 218 +++
drivers/hwmon/Kconfig | 12 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/ltc4283.c | 1808 ++++++++++++++++++++
10 files changed, 2603 insertions(+)
---
base-commit: 30a90fa04af6937493fbba20e3e923b5b5a162b4
change-id: 20260303-ltc4283-support-063f78acc5a4
--
Thanks!
- Nuno Sá
^ permalink raw reply
* [PATCH v9 3/3] gpio: gpio-ltc4283: Add support for the LTC4283 Swap Controller
From: Nuno Sá via B4 Relay @ 2026-04-06 14:31 UTC (permalink / raw)
To: linux-gpio, linux-hwmon, devicetree, linux-doc
Cc: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Linus Walleij, Bartosz Golaszewski,
Bartosz Golaszewski
In-Reply-To: <20260406-ltc4283-support-v9-0-b66cfc749261@analog.com>
From: Nuno Sá <nuno.sa@analog.com>
The LTC4283 device has up to 8 pins that can be configured as GPIOs.
Note that PGIO pins are not set as GPIOs by default so if they are
configured to be used as GPIOs we need to make sure to initialize them
to a sane default. They are set as inputs by default.
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
MAINTAINERS | 2 +
drivers/gpio/Kconfig | 15 +++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-ltc4283.c | 218 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 236 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index a63833b6fe8b..0947cdbac5e5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15163,9 +15163,11 @@ F: drivers/hwmon/ltc4282.c
LTC4283 HARDWARE MONITOR AND GPIO DRIVER
M: Nuno Sá <nuno.sa@analog.com>
+L: linux-gpio@vger.kernel.org
L: linux-hwmon@vger.kernel.org
S: Supported
F: Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml
+F: drivers/gpio/gpio-ltc4283.c
F: drivers/hwmon/ltc4283.c
LTC4286 HARDWARE MONITOR DRIVER
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b45fb799e36c..ba2621024598 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1758,6 +1758,21 @@ config GPIO_WM8994
endmenu
+menu "Auxiliary Bus GPIO drivers"
+ depends on AUXILIARY_BUS
+
+config GPIO_LTC4283
+ tristate "Analog Devices LTC4283 GPIO support"
+ depends on SENSORS_LTC4283
+ help
+ If you say yes here you want the GPIO function available in Analog
+ Devices LTC4283 Negative Voltage Hot Swap Controller.
+
+ This driver can also be built as a module. If so, the module will
+ be called gpio-ltc4283.
+
+endmenu
+
menu "PCI GPIO expanders"
depends on PCI
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index c05f7d795c43..ff37aca5029c 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -102,6 +102,7 @@ obj-$(CONFIG_GPIO_LP873X) += gpio-lp873x.o
obj-$(CONFIG_GPIO_LP87565) += gpio-lp87565.o
obj-$(CONFIG_GPIO_LPC18XX) += gpio-lpc18xx.o
obj-$(CONFIG_GPIO_LPC32XX) += gpio-lpc32xx.o
+obj-$(CONFIG_GPIO_LTC4283) += gpio-ltc4283.o
obj-$(CONFIG_GPIO_MACSMC) += gpio-macsmc.o
obj-$(CONFIG_GPIO_MADERA) += gpio-madera.o
obj-$(CONFIG_GPIO_MAX3191X) += gpio-max3191x.o
diff --git a/drivers/gpio/gpio-ltc4283.c b/drivers/gpio/gpio-ltc4283.c
new file mode 100644
index 000000000000..6609443c5d62
--- /dev/null
+++ b/drivers/gpio/gpio-ltc4283.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Analog Devices LTC4283 GPIO driver
+ *
+ * Copyright 2025 Analog Devices Inc.
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/bits.h>
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define LTC4283_PINS_MAX 8
+#define LTC4283_PGIOX_START_NR 4
+#define LTC4283_INPUT_STATUS 0x02
+#define LTC4283_PGIO_CONFIG 0x10
+#define LTC4283_PGIO_CFG_MASK(pin) \
+ GENMASK(((pin) - LTC4283_PGIOX_START_NR) * 2 + 1, (((pin) - LTC4283_PGIOX_START_NR) * 2))
+#define LTC4283_PGIO_CONFIG_2 0x11
+
+#define LTC4283_ADIO_CONFIG 0x12
+/* starts at bit 4 */
+#define LTC4283_ADIOX_CONFIG_MASK(pin) BIT((pin) + 4)
+#define LTC4283_PGIO_DIR_IN 3
+#define LTC4283_PGIO_DIR_OUT 2
+
+struct ltc4283_gpio {
+ struct gpio_chip gpio_chip;
+ struct regmap *regmap;
+};
+
+static int ltc4283_pgio_get_direction(const struct ltc4283_gpio *st, unsigned int off)
+{
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(st->regmap, LTC4283_PGIO_CONFIG, &val);
+ if (ret)
+ return ret;
+
+ val = field_get(LTC4283_PGIO_CFG_MASK(off), val);
+ if (val == LTC4283_PGIO_DIR_IN)
+ return GPIO_LINE_DIRECTION_IN;
+
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int ltc4283_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
+{
+ struct ltc4283_gpio *st = gpiochip_get_data(gc);
+ unsigned int val;
+ int ret;
+
+ if (off >= LTC4283_PGIOX_START_NR)
+ return ltc4283_pgio_get_direction(st, off);
+
+ ret = regmap_read(st->regmap, LTC4283_ADIO_CONFIG, &val);
+ if (ret)
+ return ret;
+
+ if (val & LTC4283_ADIOX_CONFIG_MASK(off))
+ return GPIO_LINE_DIRECTION_IN;
+
+ return GPIO_LINE_DIRECTION_OUT;
+}
+
+static int ltc4283_gpio_direction_set(const struct ltc4283_gpio *st,
+ unsigned int off, bool input)
+{
+ if (off >= LTC4283_PGIOX_START_NR) {
+ unsigned int val = LTC4283_PGIO_DIR_OUT;
+
+ if (input)
+ val = LTC4283_PGIO_DIR_IN;
+
+ val = field_prep(LTC4283_PGIO_CFG_MASK(off), val);
+ return regmap_update_bits(st->regmap, LTC4283_PGIO_CONFIG,
+ LTC4283_PGIO_CFG_MASK(off), val);
+ }
+
+ return regmap_update_bits(st->regmap, LTC4283_ADIO_CONFIG,
+ LTC4283_ADIOX_CONFIG_MASK(off),
+ field_prep(LTC4283_ADIOX_CONFIG_MASK(off), input));
+}
+
+static int __ltc4283_gpio_set_value(const struct ltc4283_gpio *st,
+ unsigned int off, int val)
+{
+ u32 reg = off < LTC4283_PGIOX_START_NR ? LTC4283_ADIO_CONFIG : LTC4283_PGIO_CONFIG_2;
+
+ return regmap_update_bits(st->regmap, reg, BIT(off),
+ field_prep(BIT(off), !!val));
+}
+
+static int ltc4283_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
+{
+ struct ltc4283_gpio *st = gpiochip_get_data(gc);
+
+ return ltc4283_gpio_direction_set(st, off, true);
+}
+
+static int ltc4283_gpio_direction_output(struct gpio_chip *gc, unsigned int off, int val)
+{
+ struct ltc4283_gpio *st = gpiochip_get_data(gc);
+ int ret;
+
+ ret = ltc4283_gpio_direction_set(st, off, false);
+ if (ret)
+ return ret;
+
+ return __ltc4283_gpio_set_value(st, off, val);
+}
+
+static int ltc4283_gpio_get_value(struct gpio_chip *gc, unsigned int off)
+{
+ struct ltc4283_gpio *st = gpiochip_get_data(gc);
+ unsigned int val, reg;
+ int ret, dir;
+
+ dir = ltc4283_gpio_get_direction(gc, off);
+ if (dir < 0)
+ return dir;
+
+ if (dir == GPIO_LINE_DIRECTION_IN) {
+ ret = regmap_read(st->regmap, LTC4283_INPUT_STATUS, &val);
+ if (ret)
+ return ret;
+
+ /* ADIO1 is at bit 3. */
+ if (off < LTC4283_PGIOX_START_NR)
+ return !!(val & BIT(3 - off));
+
+ /* PGIO1 is at bit 7. */
+ return !!(val & BIT(7 - (off - LTC4283_PGIOX_START_NR)));
+ }
+
+ if (off < LTC4283_PGIOX_START_NR)
+ reg = LTC4283_ADIO_CONFIG;
+ else
+ reg = LTC4283_PGIO_CONFIG_2;
+
+ ret = regmap_read(st->regmap, reg, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & BIT(off));
+}
+
+static int ltc4283_gpio_set_value(struct gpio_chip *gc, unsigned int off, int val)
+{
+ struct ltc4283_gpio *st = gpiochip_get_data(gc);
+
+ return __ltc4283_gpio_set_value(st, off, val);
+}
+
+static int ltc4283_init_valid_mask(struct gpio_chip *gc, unsigned long *valid_mask,
+ unsigned int ngpios)
+{
+ unsigned long *mask = dev_get_platdata(gc->parent);
+
+ bitmap_copy(valid_mask, mask, ngpios);
+ return 0;
+}
+
+static int ltc4283_gpio_probe(struct auxiliary_device *adev,
+ const struct auxiliary_device_id *id)
+{
+ struct device *dev = &adev->dev;
+ struct ltc4283_gpio *st;
+ struct gpio_chip *gc;
+
+ st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ st->regmap = dev_get_regmap(dev->parent, NULL);
+ if (!st->regmap)
+ return dev_err_probe(dev, -ENODEV,
+ "Failed to get regmap\n");
+
+ gc = &st->gpio_chip;
+ gc->parent = dev;
+ gc->get_direction = ltc4283_gpio_get_direction;
+ gc->direction_input = ltc4283_gpio_direction_input;
+ gc->direction_output = ltc4283_gpio_direction_output;
+ gc->get = ltc4283_gpio_get_value;
+ gc->set = ltc4283_gpio_set_value;
+ gc->init_valid_mask = ltc4283_init_valid_mask;
+ gc->can_sleep = true;
+
+ gc->base = -1;
+ gc->ngpio = LTC4283_PINS_MAX;
+ gc->label = adev->name;
+ gc->owner = THIS_MODULE;
+
+ return devm_gpiochip_add_data(dev, &st->gpio_chip, st);
+}
+
+static const struct auxiliary_device_id ltc4283_aux_id_table[] = {
+ { "ltc4283.gpio" },
+ { }
+};
+MODULE_DEVICE_TABLE(auxiliary, ltc4283_aux_id_table);
+
+static struct auxiliary_driver ltc4283_gpio_driver = {
+ .probe = ltc4283_gpio_probe,
+ .id_table = ltc4283_aux_id_table,
+};
+module_auxiliary_driver(ltc4283_gpio_driver);
+
+MODULE_AUTHOR("Nuno Sá <nuno.sa@analog.com>");
+MODULE_DESCRIPTION("GPIO LTC4283 Driver");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related
* [PATCH v9 1/3] dt-bindings: hwmon: Document the LTC4283 Swap Controller
From: Nuno Sá via B4 Relay @ 2026-04-06 14:31 UTC (permalink / raw)
To: linux-gpio, linux-hwmon, devicetree, linux-doc
Cc: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley,
Jonathan Corbet, Linus Walleij, Bartosz Golaszewski
In-Reply-To: <20260406-ltc4283-support-v9-0-b66cfc749261@analog.com>
From: Nuno Sá <nuno.sa@analog.com>
The LTC4283 is a negative voltage hot swap controller that drives an
external N-channel MOSFET to allow a board to be safely inserted and
removed from a live backplane.
Special note for the "adi,vpower-drns-enable" property. It allows to choose
between the attenuated MOSFET drain voltage or the attenuated input
voltage at the RTNS pin (effectively choosing between input or output
power). This is a system level decision not really intended to change at
runtime and hence is being added as a Firmware property.
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
.../devicetree/bindings/hwmon/adi,ltc4283.yaml | 272 +++++++++++++++++++++
MAINTAINERS | 6 +
2 files changed, 278 insertions(+)
diff --git a/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml
new file mode 100644
index 000000000000..05e2132ad4d8
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml
@@ -0,0 +1,272 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/adi,ltc4283.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: LTC4283 Negative Voltage Hot Swap Controller
+
+maintainers:
+ - Nuno Sá <nuno.sa@analog.com>
+
+description: |
+ The LTC4283 negative voltage hot swap controller drives an external N-channel
+ MOSFET to allow a board to be safely inserted and removed from a live
+ backplane.
+
+ https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4283.pdf
+
+properties:
+ compatible:
+ enum:
+ - adi,ltc4283
+
+ reg:
+ maxItems: 1
+
+ adi,rsense-nano-ohms:
+ description: Value of the sense resistor.
+
+ adi,current-limit-sense-microvolt:
+ description:
+ The current limit sense voltage of the chip is adjustable between
+ 15mV and 30mV in 1mV steps. This effectively limits the current
+ on the load.
+ minimum: 15000
+ maximum: 30000
+ default: 15000
+
+ adi,current-limit-foldback-factor:
+ description:
+ Specifies the foldback factor for the current limit. The current limit
+ can be reduced (folded back) to one of four preset levels. The value
+ represents the percentage of the current limit sense voltage to use
+ during foldback. A value of 100 means no foldback.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ enum: [10, 20, 50, 100]
+ default: 100
+
+ adi,cooling-delay-ms:
+ description:
+ Cooling time to apply after an overcurrent fault, FET bad or
+ external fault.
+ enum: [512, 1002, 2005, 4100, 8190, 16400, 32800, 65600]
+ default: 512
+
+ adi,fet-bad-timer-delay-ms:
+ description:
+ FET bad timer delay. After a FET bad status condition is detected,
+ this timer is started. If the condition persists for the
+ specified time, the FET is turned off and a fault is logged.
+ enum: [256, 512, 1002, 2005]
+ default: 256
+
+ adi,power-good-reset-on-fet:
+ description:
+ If set, resets the power good status when the MOSFET is turned off.
+ Otherwise, it resets when a low output voltage is detected.
+ type: boolean
+
+ adi,fet-turn-off-disable:
+ description:
+ If set, the MOSFET is not turned off when a FET fault is detected.
+ type: boolean
+
+ adi,tmr-pull-down-disable:
+ description: Disables 2uA pull-down current on the TMR pin.
+ type: boolean
+
+ adi,dvdt-inrush-control-disable:
+ description:
+ Disables dV/dt inrush control during startup. In dV/dt mode, the inrush
+ current is limited by controlling a constant output voltage ramp rate.
+ When disabled, the inrush control mechanism is active current limiting.
+ type: boolean
+
+ adi,fault-log-enable:
+ description:
+ If set, enables logging fault registers and ADC data into EEPROM upon a
+ fault.
+ type: boolean
+
+ adi,vpower-drns-enable:
+ description:
+ If set, enables the attenuated MOSFET drain voltage to be monitored. This
+ effectively means that the MOSFET power is monitored. If not set, the
+ attenuated input voltage (and hence input power) is monitored.
+ type: boolean
+
+ adi,external-fault-fet-off-enable:
+ description: Turns MOSFET off following an external fault.
+ type: boolean
+
+ adi,undervoltage-retry-disable:
+ description: Do not retry to turn on the MOSFET after an undervoltage fault.
+ type: boolean
+
+ adi,overvoltage-retry-disable:
+ description: Do not retry to turn on the MOSFET after an overvoltage fault.
+ type: boolean
+
+ adi,external-fault-retry-enable:
+ description: Retry to turn on the MOSFET after an external fault.
+ type: boolean
+
+ adi,overcurrent-retries:
+ description: Configures auto-retry following an Overcurrent fault.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [latch-off, "1", "7", unlimited]
+ default: latch-off
+
+ adi,fet-bad-retries:
+ description:
+ Configures auto-retry following a FET bad fault and a consequent MOSFET
+ turn off.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [latch-off, "1", "7", unlimited]
+ default: latch-off
+
+ adi,pgio1-func:
+ description: Configures the function of the PGIO1 pin.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [inverted_power_good, power_good, gpio]
+ default: inverted_power_good
+
+ adi,pgio2-func:
+ description: Configures the function of the PGIO2 pin.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [inverted_power_good, power_good, gpio, active_current_limiting]
+ default: inverted_power_good
+
+ adi,pgio3-func:
+ description: Configures the function of the PGIO3 pin.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [inverted_power_good_input, power_good_input, gpio]
+ default: inverted_power_good_input
+
+ adi,pgio4-func:
+ description: Configures the function of the PGIO4 pin.
+ $ref: /schemas/types.yaml#/definitions/string
+ enum: [inverted_external_fault, external_fault, gpio]
+ default: inverted_external_fault
+
+ adi,gpio-on-adio1:
+ description: If set, the ADIO1 pin is used as a GPIO.
+ type: boolean
+
+ adi,gpio-on-adio2:
+ description: If set, the ADIO2 pin is used as a GPIO.
+ type: boolean
+
+ adi,gpio-on-adio3:
+ description: If set, the ADIO3 pin is used as a GPIO.
+ type: boolean
+
+ adi,gpio-on-adio4:
+ description: If set, the ADIO4 pin is used as a GPIO.
+ type: boolean
+
+ gpio-controller: true
+
+ '#gpio-cells':
+ const: 2
+
+dependencies:
+ adi,gpio-on-adio1:
+ - gpio-controller
+ - '#gpio-cells'
+ adi,gpio-on-adio2:
+ - gpio-controller
+ - '#gpio-cells'
+ adi,gpio-on-adio3:
+ - gpio-controller
+ - '#gpio-cells'
+ adi,gpio-on-adio4:
+ - gpio-controller
+ - '#gpio-cells'
+ adi,external-fault-retry-enable:
+ - adi,pgio4-func
+ adi,external-fault-fet-off-enable:
+ - adi,pgio4-func
+
+required:
+ - compatible
+ - reg
+ - adi,rsense-nano-ohms
+
+allOf:
+ - if:
+ properties:
+ adi,pgio1-func:
+ const: gpio
+ required:
+ - adi,pgio1-func
+ then:
+ required:
+ - gpio-controller
+ - '#gpio-cells'
+
+ - if:
+ properties:
+ adi,pgio2-func:
+ const: gpio
+ required:
+ - adi,pgio2-func
+ then:
+ required:
+ - gpio-controller
+ - '#gpio-cells'
+
+ - if:
+ properties:
+ adi,pgio3-func:
+ const: gpio
+ required:
+ - adi,pgio3-func
+ then:
+ required:
+ - gpio-controller
+ - '#gpio-cells'
+
+ - if:
+ properties:
+ adi,pgio4-func:
+ const: gpio
+ required:
+ - adi,pgio4-func
+ then:
+ properties:
+ adi,external-fault-retry-enable: false
+ adi,external-fault-fet-off-enable: false
+ required:
+ - gpio-controller
+ - '#gpio-cells'
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ swap-controller@15 {
+ compatible = "adi,ltc4283";
+ reg = <0x15>;
+
+ adi,rsense-nano-ohms = <500>;
+ adi,current-limit-sense-microvolt = <25000>;
+ adi,current-limit-foldback-factor = <10>;
+ adi,cooling-delay-ms = <8190>;
+ adi,fet-bad-timer-delay-ms = <512>;
+
+ adi,external-fault-fet-off-enable;
+ adi,pgio4-func = "external_fault";
+
+ adi,gpio-on-adio1;
+ adi,pgio1-func = "gpio";
+ gpio-controller;
+ #gpio-cells = <2>;
+ };
+ };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index e008c2bcc187..3f727d7fdfa4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15161,6 +15161,12 @@ F: Documentation/devicetree/bindings/hwmon/adi,ltc4282.yaml
F: Documentation/hwmon/ltc4282.rst
F: drivers/hwmon/ltc4282.c
+LTC4283 HARDWARE MONITOR AND GPIO DRIVER
+M: Nuno Sá <nuno.sa@analog.com>
+L: linux-hwmon@vger.kernel.org
+S: Supported
+F: Documentation/devicetree/bindings/hwmon/adi,ltc4283.yaml
+
LTC4286 HARDWARE MONITOR DRIVER
M: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
L: linux-hwmon@vger.kernel.org
--
2.53.0
^ permalink raw reply related
* Re: [PATCH v2 07/33] rust: allow globally `clippy::incompatible_msrv`
From: Miguel Ojeda @ 2026-04-06 14:37 UTC (permalink / raw)
To: Tamir Duberstein
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <177548573697.95472.13544191227699996309.b4-review@b4>
On Mon, Apr 6, 2026 at 4:29 PM Tamir Duberstein <tamird@kernel.org> wrote:
>
> Could you add a reference to the upstream bug report [0] here?
Of course, thanks for the tags!
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH v2 32/33] rust: kbuild: support global per-version flags
From: Tamir Duberstein @ 2026-04-06 14:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260405235309.418950-33-ojeda@kernel.org>
On Mon, 06 Apr 2026 01:53:08 +0200, Miguel Ojeda <ojeda@kernel.org> wrote:
> Sometimes it is useful to gate global Rust flags per compiler version.
> For instance, we may want to disable a lint that has false positives in
> a single version [1].
>
> We already had helpers like `rustc-min-version` for that, which we use
> elsewhere, but we cannot currently use them for `rust_common_flags`,
> which contains the global flags for all Rust code (kernel and host),
> because `rustc-min-version` depends on `CONFIG_RUSTC_VERSION`, which
> does not exist when `rust_common_flags` is defined.
>
> [...]
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
--
Tamir Duberstein <tamird@kernel.org>
^ permalink raw reply
* Re: [PATCH v2 15/33] rust: macros: simplify code using `feature(extract_if)`
From: Tamir Duberstein @ 2026-04-06 14:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260405235309.418950-16-ojeda@kernel.org>
On Mon, 06 Apr 2026 01:52:51 +0200, Miguel Ojeda <ojeda@kernel.org> wrote:
> `feature(extract_if)` [1] was stabilized in Rust 1.87.0 [2], and the last
> significant change happened in Rust 1.85.0 [3] when the range parameter
> was added.
>
> That is, with our new minimum version, we can start using the feature.
>
> Thus simplify the code using the feature and remove the TODO comment.
>
> [...]
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
--
Tamir Duberstein <tamird@kernel.org>
^ permalink raw reply
* Re: [PATCH v2 07/33] rust: allow globally `clippy::incompatible_msrv`
From: Tamir Duberstein @ 2026-04-06 14:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260405235309.418950-8-ojeda@kernel.org>
On Mon, 06 Apr 2026 01:52:43 +0200, Miguel Ojeda <ojeda@kernel.org> wrote:
> diff --git a/Makefile b/Makefile
> index a63684c36d60..78f5ee173eda 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -486,6 +486,7 @@ export rust_common_flags := --edition=2021 \
> -Wclippy::as_underscore \
> -Wclippy::cast_lossless \
> -Wclippy::ignored_unit_patterns \
> + -Aclippy::incompatible_msrv \
Could you add a reference to the upstream bug report [0] here?
Link: https://github.com/rust-lang/rust-clippy/issues/14425 [0]
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
--
Tamir Duberstein <tamird@kernel.org>
^ permalink raw reply
* Re: [PATCH v2 01/33] rust: kbuild: remove `--remap-path-prefix` workarounds
From: Tamir Duberstein @ 2026-04-06 14:28 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260405235309.418950-2-ojeda@kernel.org>
On Mon, 06 Apr 2026 01:52:37 +0200, Miguel Ojeda <ojeda@kernel.org> wrote:
> Commit 8cf5b3f83614 ("Revert "kbuild, rust: use -fremap-path-prefix
> to make paths relative"") removed `--remap-path-prefix` from the build
> system, so the workarounds are not needed anymore.
>
> Thus remove them.
>
> Note that the flag has landed again in parallel in this cycle in
> commit dda135077ecc ("rust: build: remap path to avoid absolute path"),
> together with `--remap-path-scope=macro` [1]. However, they are gated on
> `rustc-option-yn, --remap-path-scope=macro`, which means they are both
> only passed starting with Rust 1.95.0 [2]:
>
> [...]
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
--
Tamir Duberstein <tamird@kernel.org>
^ permalink raw reply
* Re: [PATCH v9 02/10] x86/bhi: Make clear_bhb_loop() effective on newer CPUs
From: Jim Mattson @ 2026-04-06 14:23 UTC (permalink / raw)
To: Pawan Gupta
Cc: x86, Jon Kohler, Nikolay Borisov, H. Peter Anvin, Josh Poimboeuf,
David Kaplan, Sean Christopherson, Borislav Petkov, Dave Hansen,
Peter Zijlstra, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, KP Singh, Jiri Olsa, David S. Miller,
David Laight, Andy Lutomirski, Thomas Gleixner, Ingo Molnar,
David Ahern, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, John Fastabend, Stanislav Fomichev, Hao Luo,
Paolo Bonzini, Jonathan Corbet, linux-kernel, kvm, Asit Mallick,
Tao Zhang, bpf, netdev, linux-doc, chao.gao
In-Reply-To: <20260404034954.t7iapenzvhdpagxp@desk>
On Fri, Apr 3, 2026 at 8:50 PM Pawan Gupta
<pawan.kumar.gupta@linux.intel.com> wrote:
>
> On Fri, Apr 03, 2026 at 07:21:02PM -0700, Jim Mattson wrote:
> > On Fri, Apr 3, 2026 at 5:22 PM Pawan Gupta
> > <pawan.kumar.gupta@linux.intel.com> wrote:
> > >
> > > On Fri, Apr 03, 2026 at 04:39:54PM -0700, Jim Mattson wrote:
> > > > > Since cloud providers have greater control over userspace, the decision to
> > > > > use BHI_DIS_S or not can be left to them. KVM would simply follow what it
> > > > > is asked to do by the userspace.
> > > >
> > > > I feel like we've gone over this before, but if userspace tells KVM
> > > > not to enable BHI_DIS_S, how do we inform Windows that it needs to do
> > > > the longer clearing sequence, despite the fact that the virtual CPU is
> > > > masquerading as Ice Lake?
> > >
> > > IMO, if an OS is allergic to a hardware mitigation, and is also aware that
> > > it is virtualized, it should default to a sw mitigation that works everywhere.
> >
> > Agreed. So, without any information to the contrary, VMs should assume
> > the long BHB clearing sequence is required.
> >
> > Returning to my earlier comment, the test should be:
> >
> > + if (cpu_feature_enabled(X86_FEATURE_BHI_CTRL) ||
> > cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) {
> > + bhb_seq_outer_loop = 12;
> > + bhb_seq_inner_loop = 7;
> > + }
>
> To be clear, my comment was for an OS that doesn't want BHI_DIS_S
> under-the-hood with virtual-SPEC_CTRL. Linux doesn't have that problem,
> hardware mitigation on Linux is perfectly okay.
Today, BHI_DIS_S under-the-hood isn't offered. If the hypervisor
doesn't offer the paravirtual mitigation MSRs, the guest must assume
that the hypervisor will not set BHI_DIS_S on its behalf.
> Without virtual-SPEC_CTRL, the problem set is limited to guests that
> migrate accross Alder Lake generation CPUs. As you mentioned the change in
> MAXPHYADDR makes it unlikely.
I have been unable to make a compelling argument for not crossing this
boundary. The only applications I can point to that are broken by the
missing reserved bits are (nested) hypervisors using shadow-paging.
Since both nVMX and nSVM support TDP, the niche cache isn't a concern.
There are compelling business reasons to support seamless migration
from pre-Alder Lake to post-Alder Lake. If you know of any other
applications that will fail with a mis-emulated smaller MAXPHYADDR,
please let me know.
> With virtual-SPEC_CTRL support, guests that fall into the subset that
> migrate inspite of MAXPHYADDR change would also be mitigated. Then, on top
> of hardware mitigation, deploying the long sequence in the guest would
> incur a significant performance penalty for no good reason.
Yes, but the guest needs a way to determine whether the hypervisor
will do what's necessary to make the short sequence effective. And, in
particular, no KVM hypervisor today is prepared to do that.
When running under a hypervisor, without BHI_CTRL and without any
evidence to the contrary, the guest must assume that the longer
sequence is necessary. At the very least, we need a CPUID or MSR bit
that says, "the short BHB clearing sequence is adequate for this
vCPU."
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 14:20 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <83971700-ea17-4fd5-8985-68c798222800@baylibre.com>
> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Monday, April 6, 2026 4:57 PM
...
> >
> > I also have to mention that the oversampling commit would then implement
> > AD4691_MANUAL_CHANNEL macro which would miss the OVERSAMPLING
> > infomask, and offload_manual_channels will be declared using it.
> > More than this, that commit would also add other
> ad4691_manual_channels[]
> > and ad4693_manual_channels[] arrays that would use that MACRO as well.
> >
> > Then, chip_info would have ad4691/93_channels assigned to it by default,
> > and indio_dev->channels will later be assigned at probe, depending on the
> > mode and offload.
> >
> > If different chip_info structs would be wanted still, then my best guess is
> > to have different info structures (perhaps new types) in chip_info by default.
> > Something like *sw_info and *offload_info.
>
> Yes, this is how I would do it too.
>
Ok then, will have different chip infos and each one will have respective channels
to them. Thanks for this, too!
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 14:16 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <420dba4a-0c31-47bc-b84a-5d29702b115e@baylibre.com>
> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Monday, April 6, 2026 4:44 PM
...
> >
> > This is bad documentation on my part. "channel byte" isn't used anymore,
> > this is previous version behaviour. Right now, only 16-bits worth of actual
> > channel data are used.
> >
> Then why do we need the shift if there is no other data? Can't we rework
> the SPI message so that there is no shift?
I thought the shift is needed since DMA size is 32 bits, and value comes on the
upper word 16 bits, not on the lower ones as for CNV Burst.
Manual Mode layout: TX [CMD_HI CMD_LO DUMMY DUMMY], RX [DATA_HI DATA_LO DUMMY DUMMY]
CNV Burst layout: TX [REG_HI REG_LO DUMMY DUMMY], RX [DUMMY DUMMY DATA_HI DATA_LO]
^ permalink raw reply
* Re: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: David Lechner @ 2026-04-06 13:56 UTC (permalink / raw)
To: Sabau, Radu bogdan, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB8414BB41577A8B5A0432463FF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
On 4/6/26 8:30 AM, Sabau, Radu bogdan wrote:
>
>
>> -----Original Message-----
>> From: Sabau, Radu bogdan
>> Sent: Monday, April 6, 2026 2:08 PM
>>
>> ...
>>
>>>>> #define AD4691_CHANNEL(ch)
>>>> \
>>>>> { \
>>>>> .type = IIO_VOLTAGE, \
>>>>> @@ -122,11 +155,9 @@ struct ad4691_chip_info {
>>>>> .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),
>>>> \
>>>>> .channel = ch, \
>>>>> .scan_index = ch, \
>>>>> - .scan_type = { \
>>>>> - .sign = 'u', \
>>>>> - .realbits = 16, \
>>>>> - .storagebits = 16, \
>>>>> - }, \
>>>>> + .has_ext_scan_type = 1,
>>>> \
>>>>> + .ext_scan_type = ad4691_scan_types, \
>>>>> + .num_ext_scan_type = ARRAY_SIZE(ad4691_scan_types),
>>>> \
>>>>
>>>> Usually, we just make two separte ad4691_chip_info structs for offload
>>>> vs. not offload.
>>>>
>>>> ext_scan_type is generally only used when the scan type can change
>>>> dynamically after probe.
>>>>
>>>
>>> So, just to be clear, you are saying I should have different chip_info structs
>>> and change the triggered-buffer for offload ones if offload is present?
>>> I am asking since offload has different scan types as well, and this would
>>> mean 3 different chip_info structs for each chip -> total of 12 chip_info
>> structs,
>>> each with a different channel array, or perhaps there is a more compact way
>>> to have this implemented.
>>> I could make the channel arrays use the same macro and have the scan_type
>>> reversed to storage and shift done as parameters.
>>>
>>
>> I have given this a thought and I think this could be done in a more compact
>> way:
>>
>> 1. Parametrize AD4691_CHANNEL to accept storagebits and shift, then define
>> 4 channel
>> arrays:
>>
>> - ad4691_channels[] - 16ch + timestamp (triggered-buffer path)
>> - ad4693_channels[] - 8ch + timestamp (triggered-buffer path)
>> - ad4691_offload_cnv_channels[] - 16 entries, storagebits=32, shift =
>> 0
>> - ad4691_offload_manual_channels[] - 16 entries, storagebits=32,
>> shift=16
>>
>> The two offload arrays are shared across both chip families. Since
>> num_channels
>> bound the interation in the IIO core, the 8ch chips simply use the first 8
>> entries of
>> the 16-entry offload arrays. Triggered-buffer path would need different
>> channel
>> arrays since the timestamp index would be different, and offload doesn't use
>> timestamp.
>>
>> 2. chip_info could then stay at 2 structs, and have channels selected at probe
>> for the
>> indio_dev, or have 4 chip info structs each having its own channels assigned,
>> and only
>> num_channels could be changed at probe.
>>
>
> I also have to mention that the oversampling commit would then implement
> AD4691_MANUAL_CHANNEL macro which would miss the OVERSAMPLING
> infomask, and offload_manual_channels will be declared using it.
> More than this, that commit would also add other ad4691_manual_channels[]
> and ad4693_manual_channels[] arrays that would use that MACRO as well.
>
> Then, chip_info would have ad4691/93_channels assigned to it by default,
> and indio_dev->channels will later be assigned at probe, depending on the
> mode and offload.
>
> If different chip_info structs would be wanted still, then my best guess is
> to have different info structures (perhaps new types) in chip_info by default.
> Something like *sw_info and *offload_info.
Yes, this is how I would do it too.
> Each one would contain all the pre-defined channel arrays in them
> (channels and manual_channels) and so have ad4691_sw_info and ad4691_offload_info.
> After so, chip_info will also contain besides these 2 info structures, num_channels and max_rate.
> At probe indio_dev assignments will be made from the chip_info entirely.
>
> What's your guys take on this? I am keen to hearing your thoughts about this.
>
> Thanks,
> Radu
>
^ permalink raw reply
* Re: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: David Lechner @ 2026-04-06 13:53 UTC (permalink / raw)
To: Sabau, Radu bogdan, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB8414CB6B07EA81FB5A42436AF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
On 4/6/26 5:39 AM, Sabau, Radu bogdan wrote:
>> -----Original Message-----
>> From: David Lechner <dlechner@baylibre.com>
>> Sent: Saturday, April 4, 2026 6:57 PM
>
> ...
>
>>> +
>>> #define AD4691_CHANNEL(ch)
>> \
>>> { \
>>> .type = IIO_VOLTAGE, \
>>> @@ -122,11 +155,9 @@ struct ad4691_chip_info {
>>> .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),
>> \
>>> .channel = ch, \
>>> .scan_index = ch, \
>>> - .scan_type = { \
>>> - .sign = 'u', \
>>> - .realbits = 16, \
>>> - .storagebits = 16, \
>>> - }, \
>>> + .has_ext_scan_type = 1,
>> \
>>> + .ext_scan_type = ad4691_scan_types, \
>>> + .num_ext_scan_type = ARRAY_SIZE(ad4691_scan_types),
>> \
>>
>> Usually, we just make two separte ad4691_chip_info structs for offload
>> vs. not offload.
>>
>> ext_scan_type is generally only used when the scan type can change
>> dynamically after probe.
>>
>
> So, just to be clear, you are saying I should have different chip_info structs
> and change the triggered-buffer for offload ones if offload is present?
> I am asking since offload has different scan types as well, and this would
> mean 3 different chip_info structs for each chip -> total of 12 chip_info structs,
> each with a different channel array, or perhaps there is a more compact way
> to have this implemented.
> I could make the channel arrays use the same macro and have the scan_type
> reversed to storage and shift done as parameters.
>
> Please let me know your thoughts on this.
If it gets too complex, we can dynamically create the chip info
struct during probe. But in general we prefer to statically define
them even if it gets a little verbose. Macros usually help here.
>>> }
>>>
>>> @@ -883,6 +1184,20 @@ static ssize_t sampling_frequency_store(struct
>> device *dev,
>>> if (iio_buffer_enabled(indio_dev))
>>> return -EBUSY;
>>>
>>> + if (st->manual_mode && st->offload) {
>>> + struct spi_offload_trigger_config config = {
>>> + .type = SPI_OFFLOAD_TRIGGER_PERIODIC,
>>> + .periodic = { .frequency_hz = freq },
>>> + };
>>
>> Same comment as other patches. This needs to account for oversampling
>> ratio.
>>
>
> I am thinking that since we would have different chip_info structs, manual
> mode channels could omit the oversampling attribute, since it is not supported
> by the chip on this mode.
Yes, this would be ideal.
>> SPI_OFFLOAD_TRIGGER_PERIODIC);
>>> + if (IS_ERR(offload->trigger))
>>> + return dev_err_probe(dev, PTR_ERR(offload->trigger),
>>> + "Failed to get periodic offload
>> trigger\n");
>>> +
>>> + offload->trigger_hz = st->info->max_rate;
>>
>> I think I mentioned this elsewhere, but can we really get max_rate in manual
>> mode
>> due to the extra SPI overhead? Probably safer to start with a lower rate.
>
> You are right a slower rate would be nicer, from my tests 311kHz worked perfect
> with a 10MHz SPI frequency, but perhaps these numbers are a bit "odd".
>
> How do you feel about 100kHz for a starting sample rate?
Sounds reasonable.
>> IIO_BUFFER_DIRECTION_IN);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + indio_dev->buffer->attrs = ad4691_buffer_attrs;
>>
>> Should including ad4691_buffer_attrs depend on st->manual_mode?
>>
>> I thought it was only used when PWM is connected to CNV.
>>
>
> For offload manual mode, I thought buffer sampling frequency should also be available,
> since the offload trigger's frequency is accessible.
Ah right. Not sure what I was thinking when I wrote that.
>
>>> +
>>> + return 0;
>>> +}
>>> +
>>> static int ad4691_probe(struct spi_device *spi)
>>> {
>>> struct device *dev = &spi->dev;
>>> + struct spi_offload *spi_offload;
>>> struct iio_dev *indio_dev;
>>> struct ad4691_state *st;
>>> int ret;
>>> @@ -1232,6 +1626,13 @@ static int ad4691_probe(struct spi_device *spi)
>>> if (ret)
>>> return ret;
>>>
>>> + spi_offload = devm_spi_offload_get(dev, spi,
>> &ad4691_offload_config);
>>> + ret = PTR_ERR_OR_ZERO(spi_offload);
>>> + if (ret == -ENODEV)
>>> + spi_offload = NULL;
>>> + else if (ret)
>>> + return dev_err_probe(dev, ret, "Failed to get SPI offload\n");
>>> +
>>> indio_dev->name = st->info->name;
>>> indio_dev->info = &ad4691_info;
>>> indio_dev->modes = INDIO_DIRECT_MODE;
>>> @@ -1239,7 +1640,10 @@ static int ad4691_probe(struct spi_device *spi)
>>> indio_dev->channels = st->info->channels;
>>> indio_dev->num_channels = st->info->num_channels;
>>
>> As mentioned earlier, we generally want separate channel structs
>> for SPI offload. These will also have different num_channels because
>> there is no timestamp channel in SPI offload.
>
> If different chip_info structs will be used, wouldn't they already have specific
> channels attached to them?
>
Yes.
^ permalink raw reply
* Re: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: David Lechner @ 2026-04-06 13:44 UTC (permalink / raw)
To: Sabau, Radu bogdan, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB84145906CC191F6AB8D2D3DAF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
On 4/6/26 4:34 AM, Sabau, Radu bogdan wrote:
>> -----Original Message-----
>> From: David Lechner <dlechner@baylibre.com>
>> Sent: Saturday, April 4, 2026 6:34 PM
>
> ...
>
>>> +Selected when a ``pwms`` property is present in the device tree. The PWM
>> drives
>>> +the CNV pin independently of SPI at the configured conversion rate, and a
>> GP
>>> +pin (identified by ``interrupt-names``) asserts DATA_READY at end-of-burst
>> to
>>> +signal that the AVG_IN result registers are ready to be read.
>>> +
>>> +The IRQ handler stops the PWM, fires the IIO trigger, and the trigger
>> handler
>>
>> If we stop the PWM after an IRQ, then we don't get a consistent sample rate.
>> Ideally, we would leave the PWM running and just pick a rate slow enough
>> that
>> there is plenty of time to read the data. Otherwise, this mode doesn't seem
>> particularly useful.
>
> Should there also be a condition when setting the sampling frequency, that will
> protect from setting too fast sample rates?
I haven't figured out a good way to do this since the real max rate
depends on a lot of different things and when not using offloading,
the time it takes to do SPI xfers is non-deterministic.
>>> +IIO DMA buffer:
>>> +
>>> +* **CNV Burst offload**: the SPI engine reads AVG_IN registers with a 2-
>> byte
>>> + address phase followed by a 2-byte data phase; the 16-bit result lands in
>>> + the lower half of the 32-bit word (``shift=0``).
>>> +* **Manual offload**: each 32-bit SPI word carries the channel byte in the
>>> + first byte; the 16-bit result is returned in the upper half of the 32-bit
>>
>> I would expect the "first" byte to be in the "upper half" of the 32-bits as
>> well. This layout could be explained better.
>>
>> Also, since extra data has to be read in this mode, does this affect the max
>> conversion rate?
>
> This is bad documentation on my part. "channel byte" isn't used anymore,
> this is previous version behaviour. Right now, only 16-bits worth of actual
> channel data are used.
>
Then why do we need the shift if there is no other data? Can't we rework
the SPI message so that there is no shift?
^ permalink raw reply
* Re: [PATCH v6 3/4] iio: adc: ad4691: add triggered buffer support
From: David Lechner @ 2026-04-06 13:39 UTC (permalink / raw)
To: Sabau, Radu bogdan, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB84143905DD2E10BAC2151EEFF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
On 4/6/26 4:22 AM, Sabau, Radu bogdan wrote:
>> -----Original Message-----
>> From: David Lechner <dlechner@baylibre.com>
>> Sent: Saturday, April 4, 2026 6:12 PM
>
> ...
>
>>> +
>>> +/*
>>> + * Valid ACC_DEPTH values where the effective divisor equals the count.
>>> + * From Table 13: ACC_DEPTH = 2^N yields right-shift = N, divisor = 2^N.
>>> + */
>>> +static const int ad4691_oversampling_ratios[] = { 1, 2, 4, 8, 16, 32 };
>>
>> It would be nice to add oversampling in a separate commit as that is a
>> separate feature.
>
> Do you think this would be suitable after the offload commit?
>
Yes, I think that would be OK.
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 13:30 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB8414C570998C4C1EE59ABFBBF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
> -----Original Message-----
> From: Sabau, Radu bogdan
> Sent: Monday, April 6, 2026 2:08 PM
>
> ...
>
> > > > #define AD4691_CHANNEL(ch)
> > > \
> > > > { \
> > > > .type = IIO_VOLTAGE, \
> > > > @@ -122,11 +155,9 @@ struct ad4691_chip_info {
> > > > .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),
> > > \
> > > > .channel = ch, \
> > > > .scan_index = ch, \
> > > > - .scan_type = { \
> > > > - .sign = 'u', \
> > > > - .realbits = 16, \
> > > > - .storagebits = 16, \
> > > > - }, \
> > > > + .has_ext_scan_type = 1,
> > > \
> > > > + .ext_scan_type = ad4691_scan_types, \
> > > > + .num_ext_scan_type = ARRAY_SIZE(ad4691_scan_types),
> > > \
> > >
> > > Usually, we just make two separte ad4691_chip_info structs for offload
> > > vs. not offload.
> > >
> > > ext_scan_type is generally only used when the scan type can change
> > > dynamically after probe.
> > >
> >
> > So, just to be clear, you are saying I should have different chip_info structs
> > and change the triggered-buffer for offload ones if offload is present?
> > I am asking since offload has different scan types as well, and this would
> > mean 3 different chip_info structs for each chip -> total of 12 chip_info
> structs,
> > each with a different channel array, or perhaps there is a more compact way
> > to have this implemented.
> > I could make the channel arrays use the same macro and have the scan_type
> > reversed to storage and shift done as parameters.
> >
>
> I have given this a thought and I think this could be done in a more compact
> way:
>
> 1. Parametrize AD4691_CHANNEL to accept storagebits and shift, then define
> 4 channel
> arrays:
>
> - ad4691_channels[] - 16ch + timestamp (triggered-buffer path)
> - ad4693_channels[] - 8ch + timestamp (triggered-buffer path)
> - ad4691_offload_cnv_channels[] - 16 entries, storagebits=32, shift =
> 0
> - ad4691_offload_manual_channels[] - 16 entries, storagebits=32,
> shift=16
>
> The two offload arrays are shared across both chip families. Since
> num_channels
> bound the interation in the IIO core, the 8ch chips simply use the first 8
> entries of
> the 16-entry offload arrays. Triggered-buffer path would need different
> channel
> arrays since the timestamp index would be different, and offload doesn't use
> timestamp.
>
> 2. chip_info could then stay at 2 structs, and have channels selected at probe
> for the
> indio_dev, or have 4 chip info structs each having its own channels assigned,
> and only
> num_channels could be changed at probe.
>
I also have to mention that the oversampling commit would then implement
AD4691_MANUAL_CHANNEL macro which would miss the OVERSAMPLING
infomask, and offload_manual_channels will be declared using it.
More than this, that commit would also add other ad4691_manual_channels[]
and ad4693_manual_channels[] arrays that would use that MACRO as well.
Then, chip_info would have ad4691/93_channels assigned to it by default,
and indio_dev->channels will later be assigned at probe, depending on the
mode and offload.
If different chip_info structs would be wanted still, then my best guess is
to have different info structures (perhaps new types) in chip_info by default.
Something like *sw_info and *offload_info.
Each one would contain all the pre-defined channel arrays in them
(channels and manual_channels) and so have ad4691_sw_info and ad4691_offload_info.
After so, chip_info will also contain besides these 2 info structures, num_channels and max_rate.
At probe indio_dev assignments will be made from the chip_info entirely.
What's your guys take on this? I am keen to hearing your thoughts about this.
Thanks,
Radu
^ permalink raw reply
* Re: [PATCH 33/33] rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0
From: Miguel Ojeda @ 2026-04-06 13:21 UTC (permalink / raw)
To: Tamir Duberstein
Cc: Miguel Ojeda, Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, linux-arm-kernel, Alexandre Ghiti,
linux-riscv, nouveau, dri-devel, Rae Moar, linux-kselftest,
kunit-dev, Nick Desaulniers, Bill Wendling, Justin Stitt, llvm,
linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <177508434476.73816.11744805605122440072.b4-review@b4>
On Thu, Apr 2, 2026 at 1:02 AM Tamir Duberstein <tamird@kernel.org> wrote:
>
> Might be good to retain some of this in a code comment.
Bah, I missed this note among the rest, sorry (I didn't reply to the
ones where the commit went away due to the changes in v2) -- I agree
it wouldn't hurt to remember why it is there, even if it is already in
the Git log.
I will probably add it for tomorrow, especially if I have to rebase.
Thanks!
Cheers,
Miguel
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 11:08 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <LV9PR03MB8414CB6B07EA81FB5A42436AF75DA@LV9PR03MB8414.namprd03.prod.outlook.com>
> -----Original Message-----
> From: Sabau, Radu bogdan
> Sent: Monday, April 6, 2026 1:39 PM
...
> > > #define AD4691_CHANNEL(ch)
> > \
> > > { \
> > > .type = IIO_VOLTAGE, \
> > > @@ -122,11 +155,9 @@ struct ad4691_chip_info {
> > > .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),
> > \
> > > .channel = ch, \
> > > .scan_index = ch, \
> > > - .scan_type = { \
> > > - .sign = 'u', \
> > > - .realbits = 16, \
> > > - .storagebits = 16, \
> > > - }, \
> > > + .has_ext_scan_type = 1,
> > \
> > > + .ext_scan_type = ad4691_scan_types, \
> > > + .num_ext_scan_type = ARRAY_SIZE(ad4691_scan_types),
> > \
> >
> > Usually, we just make two separte ad4691_chip_info structs for offload
> > vs. not offload.
> >
> > ext_scan_type is generally only used when the scan type can change
> > dynamically after probe.
> >
>
> So, just to be clear, you are saying I should have different chip_info structs
> and change the triggered-buffer for offload ones if offload is present?
> I am asking since offload has different scan types as well, and this would
> mean 3 different chip_info structs for each chip -> total of 12 chip_info structs,
> each with a different channel array, or perhaps there is a more compact way
> to have this implemented.
> I could make the channel arrays use the same macro and have the scan_type
> reversed to storage and shift done as parameters.
>
I have given this a thought and I think this could be done in a more compact way:
1. Parametrize AD4691_CHANNEL to accept storagebits and shift, then define 4 channel
arrays:
- ad4691_channels[] - 16ch + timestamp (triggered-buffer path)
- ad4693_channels[] - 8ch + timestamp (triggered-buffer path)
- ad4691_offload_cnv_channels[] - 16 entries, storagebits=32, shift = 0
- ad4691_offload_manual_channels[] - 16 entries, storagebits=32, shift=16
The two offload arrays are shared across both chip families. Since num_channels
bound the interation in the IIO core, the 8ch chips simply use the first 8 entries of
the 16-entry offload arrays. Triggered-buffer path would need different channel
arrays since the timestamp index would be different, and offload doesn't use
timestamp.
2. chip_info could then stay at 2 structs, and have channels selected at probe for the
indio_dev, or have 4 chip info structs each having its own channels assigned, and only
num_channels could be changed at probe.
> Please let me know your thoughts on this.
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 10:39 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <22b44acb-bfb5-4b97-8fa2-aeb4aec704c2@baylibre.com>
> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Saturday, April 4, 2026 6:57 PM
...
> > +
> > #define AD4691_CHANNEL(ch)
> \
> > { \
> > .type = IIO_VOLTAGE, \
> > @@ -122,11 +155,9 @@ struct ad4691_chip_info {
> > .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),
> \
> > .channel = ch, \
> > .scan_index = ch, \
> > - .scan_type = { \
> > - .sign = 'u', \
> > - .realbits = 16, \
> > - .storagebits = 16, \
> > - }, \
> > + .has_ext_scan_type = 1,
> \
> > + .ext_scan_type = ad4691_scan_types, \
> > + .num_ext_scan_type = ARRAY_SIZE(ad4691_scan_types),
> \
>
> Usually, we just make two separte ad4691_chip_info structs for offload
> vs. not offload.
>
> ext_scan_type is generally only used when the scan type can change
> dynamically after probe.
>
So, just to be clear, you are saying I should have different chip_info structs
and change the triggered-buffer for offload ones if offload is present?
I am asking since offload has different scan types as well, and this would
mean 3 different chip_info structs for each chip -> total of 12 chip_info structs,
each with a different channel array, or perhaps there is a more compact way
to have this implemented.
I could make the channel arrays use the same macro and have the scan_type
reversed to storage and shift done as parameters.
Please let me know your thoughts on this.
> > }
> >
> > static const struct iio_chan_spec ad4691_channels[] = {
> > @@ -221,6 +252,17 @@ static const struct ad4691_chip_info
> ad4694_chip_info = {
> > .max_rate = 1 * HZ_PER_MHZ,
> > };
> >
...
> > }
> >
> > @@ -883,6 +1184,20 @@ static ssize_t sampling_frequency_store(struct
> device *dev,
> > if (iio_buffer_enabled(indio_dev))
> > return -EBUSY;
> >
> > + if (st->manual_mode && st->offload) {
> > + struct spi_offload_trigger_config config = {
> > + .type = SPI_OFFLOAD_TRIGGER_PERIODIC,
> > + .periodic = { .frequency_hz = freq },
> > + };
>
> Same comment as other patches. This needs to account for oversampling
> ratio.
>
I am thinking that since we would have different chip_info structs, manual
mode channels could omit the oversampling attribute, since it is not supported
by the chip on this mode.
> > +
> > + ret = spi_offload_trigger_validate(st->offload->trigger,
> &config);
> > + if (ret)
> > + return ret;
> > +
> > + st->offload->trigger_hz = config.periodic.frequency_hz;
> > + return len;
> > + }
> > +
> > ret = ad4691_set_pwm_freq(st, freq);
> > if (ret)
> > return ret;
> > @@ -968,10 +1283,23 @@ static irqreturn_t ad4691_trigger_handler(int
> irq, void *p)
> > return IRQ_HANDLED;
> > }
> >
> > +static int ad4691_get_current_scan_type(const struct iio_dev *indio_dev,
> > + const struct iio_chan_spec *chan)
> > +{
> > + struct ad4691_state *st = iio_priv(indio_dev);
> > +
> > + if (!st->offload)
> > + return AD4691_SCAN_TYPE_NORMAL;
> > + if (st->manual_mode)
> > + return AD4691_SCAN_TYPE_OFFLOAD_MANUAL;
> > + return AD4691_SCAN_TYPE_OFFLOAD_CNV;
> > +}
> > +
> > static const struct iio_info ad4691_info = {
> > .read_raw = &ad4691_read_raw,
> > .write_raw = &ad4691_write_raw,
> > .read_avail = &ad4691_read_avail,
> > + .get_current_scan_type = &ad4691_get_current_scan_type,
> > .debugfs_reg_access = &ad4691_reg_access,
> > };
> >
> > @@ -1195,9 +1523,75 @@ static int ad4691_setup_triggered_buffer(struct
> iio_dev *indio_dev,
> >
> &ad4691_manual_buffer_setup_ops);
> > }
> >
> > +static int ad4691_setup_offload(struct iio_dev *indio_dev,
> > + struct ad4691_state *st,
> > + struct spi_offload *spi_offload)
> > +{
> > + struct device *dev = regmap_get_device(st->regmap);
> > + struct ad4691_offload_state *offload;
> > + struct dma_chan *rx_dma;
> > + int ret;
> > +
> > + offload = devm_kzalloc(dev, sizeof(*offload), GFP_KERNEL);
> > + if (!offload)
> > + return -ENOMEM;
> > +
> > + offload->spi = spi_offload;
> > + st->offload = offload;
> > +
> > + if (st->manual_mode) {
> > + offload->trigger =
> > + devm_spi_offload_trigger_get(dev, offload->spi,
> > +
> SPI_OFFLOAD_TRIGGER_PERIODIC);
> > + if (IS_ERR(offload->trigger))
> > + return dev_err_probe(dev, PTR_ERR(offload->trigger),
> > + "Failed to get periodic offload
> trigger\n");
> > +
> > + offload->trigger_hz = st->info->max_rate;
>
> I think I mentioned this elsewhere, but can we really get max_rate in manual
> mode
> due to the extra SPI overhead? Probably safer to start with a lower rate.
You are right a slower rate would be nicer, from my tests 311kHz worked perfect
with a 10MHz SPI frequency, but perhaps these numbers are a bit "odd".
How do you feel about 100kHz for a starting sample rate?
>
> > + } else {
> > + struct spi_offload_trigger_info trigger_info = {
> > + .fwnode = dev_fwnode(dev),
> > + .ops = &ad4691_offload_trigger_ops,
> > + .priv = st,
> > + };
> > +
> > + ret = devm_spi_offload_trigger_register(dev, &trigger_info);
> > + if (ret)
> > + return dev_err_probe(dev, ret,
> > + "Failed to register offload
> trigger\n");
> > +
> > + offload->trigger =
> > + devm_spi_offload_trigger_get(dev, offload->spi,
> > +
> SPI_OFFLOAD_TRIGGER_DATA_READY);
> > + if (IS_ERR(offload->trigger))
> > + return dev_err_probe(dev, PTR_ERR(offload->trigger),
> > + "Failed to get DATA_READY offload
> trigger\n");
> > + }
> > +
> > + rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
> offload->spi);
> > + if (IS_ERR(rx_dma))
> > + return dev_err_probe(dev, PTR_ERR(rx_dma),
> > + "Failed to get offload RX DMA channel\n");
> > +
> > + if (st->manual_mode)
> > + indio_dev->setup_ops =
> &ad4691_manual_offload_buffer_setup_ops;
> > + else
> > + indio_dev->setup_ops =
> &ad4691_cnv_burst_offload_buffer_setup_ops;
> > +
> > + ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev,
> rx_dma,
> > +
> IIO_BUFFER_DIRECTION_IN);
> > + if (ret)
> > + return ret;
> > +
> > + indio_dev->buffer->attrs = ad4691_buffer_attrs;
>
> Should including ad4691_buffer_attrs depend on st->manual_mode?
>
> I thought it was only used when PWM is connected to CNV.
>
For offload manual mode, I thought buffer sampling frequency should also be available,
since the offload trigger's frequency is accessible.
> > +
> > + return 0;
> > +}
> > +
> > static int ad4691_probe(struct spi_device *spi)
> > {
> > struct device *dev = &spi->dev;
> > + struct spi_offload *spi_offload;
> > struct iio_dev *indio_dev;
> > struct ad4691_state *st;
> > int ret;
> > @@ -1232,6 +1626,13 @@ static int ad4691_probe(struct spi_device *spi)
> > if (ret)
> > return ret;
> >
> > + spi_offload = devm_spi_offload_get(dev, spi,
> &ad4691_offload_config);
> > + ret = PTR_ERR_OR_ZERO(spi_offload);
> > + if (ret == -ENODEV)
> > + spi_offload = NULL;
> > + else if (ret)
> > + return dev_err_probe(dev, ret, "Failed to get SPI offload\n");
> > +
> > indio_dev->name = st->info->name;
> > indio_dev->info = &ad4691_info;
> > indio_dev->modes = INDIO_DIRECT_MODE;
> > @@ -1239,7 +1640,10 @@ static int ad4691_probe(struct spi_device *spi)
> > indio_dev->channels = st->info->channels;
> > indio_dev->num_channels = st->info->num_channels;
>
> As mentioned earlier, we generally want separate channel structs
> for SPI offload. These will also have different num_channels because
> there is no timestamp channel in SPI offload.
If different chip_info structs will be used, wouldn't they already have specific
channels attached to them?
^ permalink raw reply
* RE: [PATCH v6 4/4] iio: adc: ad4691: add SPI offload support
From: Sabau, Radu bogdan @ 2026-04-06 9:34 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <1d0d41c8-7867-4459-a91a-a2c6774b1885@baylibre.com>
> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Saturday, April 4, 2026 6:34 PM
...
> >
> > Add driver documentation under Documentation/iio/ad4691.rst covering
> > operating modes, oversampling, reference voltage, SPI offload paths,
> > and buffer data layout; register in MAINTAINERS and index.rst
>
> Documentation should be separate patch. It covers more than just SPI
> offload.
>
Noted. Thanks for this.
> >
> > Kconfig gains a dependency on IIO_BUFFER_DMAENGINE.
> >
> > Signed-off-by: Radu Sabau <radu.sabau@analog.com>
> > ---
...
> > +Selected when a ``pwms`` property is present in the device tree. The PWM
> drives
> > +the CNV pin independently of SPI at the configured conversion rate, and a
> GP
> > +pin (identified by ``interrupt-names``) asserts DATA_READY at end-of-burst
> to
> > +signal that the AVG_IN result registers are ready to be read.
> > +
> > +The IRQ handler stops the PWM, fires the IIO trigger, and the trigger
> handler
>
> If we stop the PWM after an IRQ, then we don't get a consistent sample rate.
> Ideally, we would leave the PWM running and just pick a rate slow enough
> that
> there is plenty of time to read the data. Otherwise, this mode doesn't seem
> particularly useful.
Should there also be a condition when setting the sampling frequency, that will
protect from setting too fast sample rates?
>
> > +reads all active ``AVG_IN(n)`` registers in a single optimised SPI message and
> > +pushes the scan to the buffer.
> > +
> > +The buffer sampling frequency (i.e. the PWM rate) is controlled by the
> > +``sampling_frequency`` attribute on the IIO buffer. Valid values span from
> the
> > +chip's minimum oscillator rate up to its maximum conversion rate
> > +(500 kSPS for AD4691/AD4693, 1 MSPS for AD4692/AD4694).
>
> Valid, but not usable without SPI offload.
The PWM is also be used with triggered-buffer in CNV Burst Mode.
>
> > +
> > +Autonomous Mode (idle / single-shot)
> > +-------------------------------------
> > +
...
> > +
> > +Manual offload
> > +--------------
> > +
> > +Used when no ``pwms`` property is present and SPI offload is available.
> > +
> > +A periodic SPI offload trigger controls the conversion rate. On each trigger
> > +period, the SPI engine executes an N+1 transfer message (same pipelined
> scheme
>
> How does this work with oversampling?
As per previous versions discussions, Manual Mode doesn't support oversampling,
since the chip only transfers the raw unfiltered 16-bit data without register interaction
in this mode.
>
> > +as software Manual Mode) and streams the data directly to the IIO DMA
> buffer.
...
> > +IIO DMA buffer:
> > +
> > +* **CNV Burst offload**: the SPI engine reads AVG_IN registers with a 2-
> byte
> > + address phase followed by a 2-byte data phase; the 16-bit result lands in
> > + the lower half of the 32-bit word (``shift=0``).
> > +* **Manual offload**: each 32-bit SPI word carries the channel byte in the
> > + first byte; the 16-bit result is returned in the upper half of the 32-bit
>
> I would expect the "first" byte to be in the "upper half" of the 32-bits as
> well. This layout could be explained better.
>
> Also, since extra data has to be read in this mode, does this affect the max
> conversion rate?
This is bad documentation on my part. "channel byte" isn't used anymore,
this is previous version behaviour. Right now, only 16-bits worth of actual
channel data are used.
>
> > + word (``shift=16``).
> > +
> > +The ``in_voltageN_type`` sysfs attribute reflects the active scan type.
> > +
> > +
> > +Unimplemented features
> > +======================
> > +
> > +* GPIO controller functionality of the GP pins
> > +* Clamp status and overrange events
> > +* Raw accumulator (ACC_IN) and accumulator status registers
> > +* ADC_BUSY and overrun status interrupts
^ permalink raw reply
* RE: [PATCH v6 3/4] iio: adc: ad4691: add triggered buffer support
From: Sabau, Radu bogdan @ 2026-04-06 9:22 UTC (permalink / raw)
To: David Lechner, Lars-Peter Clausen, Hennerich, Michael,
Jonathan Cameron, Sa, Nuno, Andy Shevchenko, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Uwe Kleine-König,
Liam Girdwood, Mark Brown, Linus Walleij, Bartosz Golaszewski,
Philipp Zabel, Jonathan Corbet, Shuah Khan
Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org
In-Reply-To: <e38e5b97-e90f-4613-a15e-6c3d08cd77f7@baylibre.com>
> -----Original Message-----
> From: David Lechner <dlechner@baylibre.com>
> Sent: Saturday, April 4, 2026 6:12 PM
...
> > +
> > +/*
> > + * Valid ACC_DEPTH values where the effective divisor equals the count.
> > + * From Table 13: ACC_DEPTH = 2^N yields right-shift = N, divisor = 2^N.
> > + */
> > +static const int ad4691_oversampling_ratios[] = { 1, 2, 4, 8, 16, 32 };
>
> It would be nice to add oversampling in a separate commit as that is a
> separate feature.
Do you think this would be suitable after the offload commit?
>
> Oversampling also affects sampling frequency. When there isn't oversampling,
> sample rate == conversion rate. However, with oversampling, sample rate ==
> conversion rate / oversampling ratio (because each sample involves #OSR
> conversions).
>
> So more code will be required to make IIO_CHAN_INFO_SAMP_FREQ
> attributes
> (both read/write_raw and read_avail) adjust the values based on the current
> oversampling ratio.
I agree with this, the sampling frequency differs when oversampling is used.
Will add that in the next version.
>
> > +
> > static const struct ad4691_chip_info ad4691_chip_info = {
> > .channels = ad4691_channels,
...
> > +
> > + st->scan_msg.spi = spi;
>
> This isn't how the SPI framework is intended to be used. We should
> have st->spi = spi in probe instead.
You are right. The spi pointer was removed from struct in earlier versions
since the message wasn't pre-prepared back then, though now it is needed.
>
> > +
> > + ret = spi_optimize_message(spi, &st->scan_msg);
> > + if (ret) {
...
> > +};
> > +
> > +static irqreturn_t ad4691_irq(int irq, void *private)
> > +{
> > + struct iio_dev *indio_dev = private;
> > + struct ad4691_state *st = iio_priv(indio_dev);
> > +
> > + /*
> > + * GPx has asserted: stop conversions before reading so the
>
> Does this happen per-channel or only once per complete sequence?
>
This one happens per complete sequence.
^ permalink raw reply
* Re: [PATCH v2 00/33] rust: bump minimum Rust and `bindgen` versions
From: Miguel Ojeda @ 2026-04-06 9:03 UTC (permalink / raw)
To: Miguel Ojeda
Cc: Nathan Chancellor, Nicolas Schier, Danilo Krummrich,
Andreas Hindborg, Catalin Marinas, Will Deacon, Paul Walmsley,
Palmer Dabbelt, Albert Ou, Alexandre Courbot, David Airlie,
Simona Vetter, Brendan Higgins, David Gow, Greg Kroah-Hartman,
Arve Hjønnevåg, Todd Kjos, Christian Brauner,
Carlos Llamas, Alice Ryhl, Jonathan Corbet, Boqun Feng, Gary Guo,
Björn Roy Baron, Benno Lossin, Trevor Gross, rust-for-linux,
linux-kbuild, Lorenzo Stoakes, Vlastimil Babka, Liam R . Howlett,
Uladzislau Rezki, linux-block, moderated for non-subscribers,
Alexandre Ghiti, linux-riscv, nouveau, dri-devel, Rae Moar,
linux-kselftest, kunit-dev, Nick Desaulniers, Bill Wendling,
Justin Stitt, llvm, linux-kernel, Shuah Khan, linux-doc
In-Reply-To: <20260405235309.418950-1-ojeda@kernel.org>
On Mon, Apr 6, 2026 at 1:53 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> Debian Trixie was released with `bindgen` 0.71.1, which it also still
> uses to this day [4].
>
> Debian Trixie's release happened on 2025-08-09 [5], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new versions, i.e.
>
> - Rust: 1.78.0 -> 1.85.0
> - bindgen: 0.65.1 -> 0.71.1
>
> There are a few main parts to the series, in this order:
>
> - A few cleanups that can be performed before the bumps.
> - The Rust bump (and its cleanups).
> - The `bindgen` bump (and its cleanups).
> - Documentation updates.
> - The `cfi_encoding` patch, added here, which needs the bump.
> - The per-version flags support and a Clippy cleanup on top.
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://packages.debian.org/trixie/bindgen [4]
> Link: https://www.debian.org/releases/trixie/ [5]
Applied series to `rust-next` -- thanks everyone!
Let's see if we find any issue in -next.
(If someone wants to give tags today, then I am happy to pick them up)
Cheers,
Miguel
^ permalink raw reply
* Re: [PATCH v2] docs: fix typos and duplicated words across documentation
From: Randy Dunlap @ 2026-04-06 5:00 UTC (permalink / raw)
To: Manuel Cortez, linux-doc, corbet
In-Reply-To: <20260406030323.1196-1-mdjesuscv@gmail.com>
On 4/5/26 8:03 PM, Manuel Cortez wrote:
> Fix the following typos and duplicated words:
>
> - admin-guide/pm/intel-speed-select.rst: "weather" -> "whether"
> - core-api/real-time/differences.rst: "the the" -> "the"
> - admin-guide/bcache.rst: "to to" -> "to"
>
> Signed-off-by: Manuel Cortez <mdjesuscv@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
> ---
> Changes in v2:
> - Dropped the networking/switchdev.rst change as "is in in" is correct
> per Randy Dunlap's review.
>
> Documentation/admin-guide/bcache.rst | 2 +-
> Documentation/admin-guide/pm/intel-speed-select.rst | 2 +-
> Documentation/core-api/real-time/differences.rst | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/bcache.rst b/Documentation/admin-guide/bcache.rst
> index f71f349553e4..325816edbdab 100644
> --- a/Documentation/admin-guide/bcache.rst
> +++ b/Documentation/admin-guide/bcache.rst
> @@ -618,7 +618,7 @@ cache_replacement_policy
> One of either lru, fifo or random.
>
> freelist_percent
> - Size of the freelist as a percentage of nbuckets. Can be written to to
> + Size of the freelist as a percentage of nbuckets. Can be written to
> increase the number of buckets kept on the freelist, which lets you
> artificially reduce the size of the cache at runtime. Mostly for testing
> purposes (i.e. testing how different size caches affect your hit rate).
> diff --git a/Documentation/admin-guide/pm/intel-speed-select.rst b/Documentation/admin-guide/pm/intel-speed-select.rst
> index a2bfb971654f..dec2a25f10bc 100644
> --- a/Documentation/admin-guide/pm/intel-speed-select.rst
> +++ b/Documentation/admin-guide/pm/intel-speed-select.rst
> @@ -287,7 +287,7 @@ level.
> Check presence of other Intel(R) SST features
> ---------------------------------------------
>
> -Each of the performance profiles also specifies weather there is support of
> +Each of the performance profiles also specifies whether there is support of
> other two Intel(R) SST features (Intel(R) Speed Select Technology - Base Frequency
> (Intel(R) SST-BF) and Intel(R) Speed Select Technology - Turbo Frequency (Intel
> SST-TF)).
> diff --git a/Documentation/core-api/real-time/differences.rst b/Documentation/core-api/real-time/differences.rst
> index 83ec9aa1c61a..a129570dab5a 100644
> --- a/Documentation/core-api/real-time/differences.rst
> +++ b/Documentation/core-api/real-time/differences.rst
> @@ -213,7 +213,7 @@ to suspend until the callback completes, ensuring forward progress without
> risking livelock.
>
> In order to solve the problem at the API level, the sequence locks were extended
> -to allow a proper handover between the the spinning reader and the maybe
> +to allow a proper handover between the spinning reader and the maybe
> blocked writer.
>
> Sequence locks
--
~Randy
^ permalink raw reply
* [PATCH v2] docs: fix typos and duplicated words across documentation
From: Manuel Cortez @ 2026-04-06 3:03 UTC (permalink / raw)
To: linux-doc, corbet; +Cc: rdunlap, Manuel Cortez
In-Reply-To: <20260405030359.7392-1-mdjesuscv@gmail.com>
Fix the following typos and duplicated words:
- admin-guide/pm/intel-speed-select.rst: "weather" -> "whether"
- core-api/real-time/differences.rst: "the the" -> "the"
- admin-guide/bcache.rst: "to to" -> "to"
Signed-off-by: Manuel Cortez <mdjesuscv@gmail.com>
---
Changes in v2:
- Dropped the networking/switchdev.rst change as "is in in" is correct
per Randy Dunlap's review.
Documentation/admin-guide/bcache.rst | 2 +-
Documentation/admin-guide/pm/intel-speed-select.rst | 2 +-
Documentation/core-api/real-time/differences.rst | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/bcache.rst b/Documentation/admin-guide/bcache.rst
index f71f349553e4..325816edbdab 100644
--- a/Documentation/admin-guide/bcache.rst
+++ b/Documentation/admin-guide/bcache.rst
@@ -618,7 +618,7 @@ cache_replacement_policy
One of either lru, fifo or random.
freelist_percent
- Size of the freelist as a percentage of nbuckets. Can be written to to
+ Size of the freelist as a percentage of nbuckets. Can be written to
increase the number of buckets kept on the freelist, which lets you
artificially reduce the size of the cache at runtime. Mostly for testing
purposes (i.e. testing how different size caches affect your hit rate).
diff --git a/Documentation/admin-guide/pm/intel-speed-select.rst b/Documentation/admin-guide/pm/intel-speed-select.rst
index a2bfb971654f..dec2a25f10bc 100644
--- a/Documentation/admin-guide/pm/intel-speed-select.rst
+++ b/Documentation/admin-guide/pm/intel-speed-select.rst
@@ -287,7 +287,7 @@ level.
Check presence of other Intel(R) SST features
---------------------------------------------
-Each of the performance profiles also specifies weather there is support of
+Each of the performance profiles also specifies whether there is support of
other two Intel(R) SST features (Intel(R) Speed Select Technology - Base Frequency
(Intel(R) SST-BF) and Intel(R) Speed Select Technology - Turbo Frequency (Intel
SST-TF)).
diff --git a/Documentation/core-api/real-time/differences.rst b/Documentation/core-api/real-time/differences.rst
index 83ec9aa1c61a..a129570dab5a 100644
--- a/Documentation/core-api/real-time/differences.rst
+++ b/Documentation/core-api/real-time/differences.rst
@@ -213,7 +213,7 @@ to suspend until the callback completes, ensuring forward progress without
risking livelock.
In order to solve the problem at the API level, the sequence locks were extended
-to allow a proper handover between the the spinning reader and the maybe
+to allow a proper handover between the spinning reader and the maybe
blocked writer.
Sequence locks
--
2.51.0
^ permalink raw reply related
page: next (older) | prev (newer) | latest
- recent:[subjects (threaded)|topics (new)|topics (active)]
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox