hwmon: add MP2891 driver

Add support for MPS VR controller mp2891. This driver exposes
telemetry and limit value readings and writtings.
Signed-off-by: Noah Wang <noahwang.wang@outlook.com>
Link: https://lore.kernel.org/r/SEYPR04MB64828A352836982C0184AA10FAD62@SEYPR04MB6482.apcprd04.prod.outlook.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -165,6 +165,7 @@ Hardware Monitoring Kernel Drivers
    mlxreg-fan
    mp2856
    mp2888
+   mp2891
    mp2975
    mp2993
    mp5023

Documentation/hwmon/mp2891.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp2891
+====================
+
+Supported chips:
+
+  * MPS mp2891
+
+    Prefix: 'mp2891'
+
+  * Datasheet
+
+    Publicly available at the MPS website : https://www.monolithicpower.com/en/mp2891.html
+
+Author:
+
+	Noah Wang <noahwang.wang@outlook.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MP2891 Multi-phase Digital VR Controller.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+Device supports direct and linear format for reading input voltage,
+output voltage, input current, output current, input power, output
+power, and temperature.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+**in1_lcrit**
+
+**in1_lcrit_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_crit**
+
+**in2_crit_alarm**
+
+**in2_lcrit**
+
+**in2_lcrit_alarm**
+
+**in2_min**
+
+**in2_min_alarm**
+
+**in3_input**
+
+**in3_label**
+
+**in3_crit**
+
+**in3_crit_alarm**
+
+**in3_lcrit**
+
+**in3_lcrit_alarm**
+
+**in3_min**
+
+**in3_min_alarm**
+
+The driver provides the following attributes for input current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+**curr2_input**
+
+**curr2_label**
+
+**curr2_max**
+
+**curr2_max_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr3_input**
+
+**curr3_label**
+
+**curr3_crit**
+
+**curr3_crit_alarm**
+
+**curr3_max**
+
+**curr3_max_alarm**
+
+**curr4_input**
+
+**curr4_label**
+
+**curr4_crit**
+
+**curr4_crit_alarm**
+
+**curr4_max**
+
+**curr4_max_alarm**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+**power1_max**
+
+**power1_alarm**
+
+**power2_input**
+
+**power2_label**
+
+**power2_max**
+
+**power2_alarm**
+
+The driver provides the following attributes for output power:
+
+**power3_input**
+
+**power3_label**
+
+**power4_input**
+
+**power4_label**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
+
+**temp1_max**
+
+**temp1_max_alarm**
+
+**temp2_input**
+
+**temp2_crit**
+
+**temp2_crit_alarm**
+
+**temp2_max**
+
+**temp2_max_alarm**

MAINTAINERS

@@ -15258,6 +15258,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/leds/backlight/mps,mp3309c.yaml
 F:	drivers/video/backlight/mp3309c.c
 
+MPS MP2891 DRIVER
+M:	Noah Wang <noahwang.wang@outlook.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/mp2891.rst
+F:	drivers/hwmon/pmbus/mp2891.c
+
 MPS MP2993 DRIVER
 M:	Noah Wang <noahwang.wang@outlook.com>
 L:	linux-hwmon@vger.kernel.org

drivers/hwmon/pmbus/Kconfig

@@ -337,6 +337,15 @@ config SENSORS_MP2888
 	  This driver can also be built as a module. If so, the module will
 	  be called mp2888.
 
+config SENSORS_MP2891
+    tristate "MPS MP2891"
+    help
+      If you say yes here you get hardware monitoring support for MPS
+      MP2891 Dual Loop Digital Multi-Phase Controller.
+
+      This driver can also be built as a module. If so, the module will
+      be called mp2891.
+
 config SENSORS_MP2975
 	tristate "MPS MP2975"
 	help

drivers/hwmon/pmbus/Makefile

@@ -36,6 +36,7 @@ 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-$(CONFIG_SENSORS_MP2891)	+= mp2891.o
 obj-$(CONFIG_SENSORS_MP2975)	+= mp2975.o
 obj-$(CONFIG_SENSORS_MP2993)	+= mp2993.o
 obj-$(CONFIG_SENSORS_MP5023)	+= mp5023.o