hwmon: (pmbus) Add support for MPS Multi-phase mp2856/mp2857 controller

Add support for mp2856/mp2857 device from Monolithic Power Systems, Inc.
(MPS) vendor. This is a dual-loop, digital, multi-phase,
modulation controller.
Signed-off-by: Peter Yin <peteryin.openbmc@gmail.com>
Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
Link: https://lore.kernel.org/r/20231211160519.21254-3-potin.lai.pt@gmail.com
[groeck: Fix checkpatch issues, use i2c_get_match_data()]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -158,6 +158,7 @@ Hardware Monitoring Kernel Drivers
    mcp3021
    menf21bmc
    mlxreg-fan
+   mp2856
    mp2888
    mp2975
    mp5023

Documentation/hwmon/mp2856.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp2856
+====================
+
+Supported chips:
+
+  * MPS MP2856
+
+    Prefix: 'mp2856'
+
+  * MPS MP2857
+
+    Prefix: 'mp2857'
+
+Author:
+
+	Peter Yin <peter.yin@quantatw.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+vendor dual-loop, digital, multi-phase controller MP2856/MP2857
+
+This device:
+
+- Supports up to two power rail.
+- Supports two pages 0 and 1 for and also pages 2 for configuration.
+- Can configured VOUT readout in direct or VID format and allows
+  setting of different formats on rails 1 and 2. For VID the following
+  protocols are available: AMD SVI3 mode with 5-mV/LSB.
+
+Device supports:
+
+- SVID interface.
+- AVSBus interface.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+Device supports direct format for reading output current, output voltage,
+input and output power and temperature.
+Device supports linear format for reading input voltage and input power.
+Device supports VID and direct formats for reading output voltage.
+The below VID modes are supported: AMD SVI3.
+
+The driver provides the following sysfs attributes for current measurements:
+
+- indexes 1  for "iin";
+- indexes 2, 3 for "iout";
+
+**curr[1-3]_alarm**
+
+**curr[1-3]_input**
+
+**curr[1-3]_label**
+
+The driver provides the following sysfs attributes for voltage measurements.
+
+- indexes 1 for "vin";
+- indexes 2, 3 for "vout";
+
+**in[1-3]_crit**
+
+**in[1-3]_crit_alarm**
+
+**in[1-3]_input**
+
+**in[1-3]_label**
+
+**in[1-3]_lcrit**
+
+**in[1-3]_lcrit_alarm**
+
+The driver provides the following sysfs attributes for power measurements.
+
+- indexes 1 for "pin";
+- indexes 2, 3 for "pout";
+
+**power[1-3]_alarm**
+
+**power[1-3]_input**
+
+**power[1-3]_label**
+
+The driver provides the following sysfs attributes for temperature measurements.
+
+**temp[1-2]_crit**
+
+**temp[1-2]_crit_alarm**
+
+**temp[1-2]_input**
+
+**temp[1-2]_max**
+
+**temp[1-2]_max_alarm**

drivers/hwmon/pmbus/Kconfig

@@ -309,6 +309,15 @@ config SENSORS_MAX8688
 	  This driver can also be built as a module. If so, the module will
 	  be called max8688.
 
+config SENSORS_MP2856
+	tristate "MPS MP2856"
+	help
+	  If you say yes here you get hardware monitoring support for MPS
+	  MP2856 MP2857 Dual Loop Digital Multi-Phase Controller.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called mp2856.
+
 config SENSORS_MP2888
 	tristate "MPS MP2888"
 	help

drivers/hwmon/pmbus/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_SENSORS_MAX20751)	+= max20751.o
 obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
 obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
+obj-$(CONFIG_SENSORS_MP2856)	+= mp2856.o
 obj-$(CONFIG_SENSORS_MP2888)	+= mp2888.o
 obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
 obj-$(CONFIG_SENSORS_MP5023)	+= mp5023.o