hwmon: (pmbus/pim4328) Add documentation for the pim4328 PMBus driver

Add documentation and index link for pim4328 PMBus driver.
Signed-off-by: Erik Rosen <erik.rosen@metormote.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/index.rst

@@ -151,6 +151,7 @@ Hardware Monitoring Kernel Drivers
    pc87360
    pc87427
    pcf8591
+   pim4328
    pm6764tr
    pmbus
    powr1220

Documentation/hwmon/pim4328.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver pim4328
+=====================
+
+Supported chips:
+
+  * Flex PIM4328
+
+    Prefix: 'pim4328', 'bmr455'
+
+    Addresses scanned: -
+
+    Datasheet:
+
+https://flexpowermodules.com/resources/fpm-techspec-pim4328
+
+  * Flex PIM4820
+
+    Prefixes: 'pim4820'
+
+    Addresses scanned: -
+
+    Datasheet: https://flexpowermodules.com/resources/fpm-techspec-pim4820
+
+  * Flex PIM4006, PIM4106, PIM4206, PIM4306, PIM4406
+
+    Prefixes: 'pim4006', 'pim4106', 'pim4206', 'pim4306', 'pim4406'
+
+    Addresses scanned: -
+
+    Datasheet: https://flexpowermodules.com/resources/fpm-techspec-pim4006
+
+Author: Erik Rosen <erik.rosen@metormote.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Flex PIM4328 and
+compatible digital power interface modules.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst and Documentation.hwmon/pmbus-core for details
+on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
+details.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. All attributes are read-only.
+
+======================= ========================================================
+in1_label		"vin"
+in1_input		Measured input voltage.
+in1_alarm		Input voltage alarm.
+
+in2_label		"vin.0"
+in2_input		Measured input voltage on input A.
+
+			PIM4328 and PIM4X06
+
+in3_label		"vin.1"
+in3_input		Measured input voltage on input B.
+
+			PIM4328 and PIM4X06
+
+in4_label		"vcap"
+in4_input		Measured voltage on holdup capacitor.
+
+			PIM4328
+
+curr1_label		"iin.0"
+curr1_input		Measured input current on input A.
+
+			PIM4X06
+
+curr2_label		"iin.1"
+curr2_input		Measured input current on input B.
+
+			PIM4X06
+
+currX_label		"iout1"
+currX_input		Measured output current.
+currX_alarm		Output current alarm.
+
+			X is 1 for PIM4820, 3 otherwise.
+
+temp1_input		Measured temperature.
+temp1_alarm		High temperature alarm.
+======================= ========================================================