hwmon: add MP9941 driver

Add support for MPS step-down converter mp9941. 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/SEYPR04MB648294005D55F70736B519F6FAC72@SEYPR04MB6482.apcprd04.prod.outlook.com
[groeck: Include bitfield.h (for FIELD_PREP) and bits.h (for GENMASK)]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

2 files changed, 93 insertions, 0 deletions

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 7424cbf36ae1..e92a3d5c7b59 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -169,6 +169,7 @@ Hardware Monitoring Kernel Drivers
    mp2993
    mp5023
    mp5990
+   mp9941
    mpq8785
    nct6683
    nct6775
diff --git a/Documentation/hwmon/mp9941.rst b/Documentation/hwmon/mp9941.rst
new file mode 100644
index 000000000000..1274fa20e256
--- /dev/null
+++ b/Documentation/hwmon/mp9941.rst
@@ -0,0 +1,92 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver mp9941
+====================
+
+Supported chips:
+
+  * MPS mp9941
+
+    Prefix: 'mp9941'
+
+  * Datasheet
+    https://scnbwymvp-my.sharepoint.com/:f:/g/personal/admin_scnbwy_com/Eth4kX1_J1hMsaASHiOYL4QBHU5a75r-tRfLKbHnJFdKLQ?e=vxj3DF
+
+Author:
+
+	Noah Wang <noahwang.wang@outlook.com>
+
+Description
+-----------
+
+This driver implements support for Monolithic Power Systems, Inc. (MPS)
+MP9941 digital step-down converter.
+
+Device compliant with:
+
+- PMBus rev 1.3 interface.
+
+The driver exports the following attributes via the 'sysfs' files
+for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_crit**
+
+**in1_crit_alarm**
+
+The driver provides the following attributes for output voltage:
+
+**in2_input**
+
+**in2_label**
+
+**in2_lcrit**
+
+**in2_lcrit_alarm**
+
+**in2_rated_max**
+
+**in2_rated_min**
+
+The driver provides the following attributes for input current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr2_input**
+
+**curr2_label**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**
+
+The driver provides the following attributes for output power:
+
+**power2_input**
+
+**power2_label**
+
+The driver provides the following attributes for temperature:
+
+**temp1_input**
+
+**temp1_crit**
+
+**temp1_crit_alarm**
+
+**temp1_max**
+
+**temp1_max_alarm**