hwmon: (menf21bmc) Introduce MEN14F021P00 BMC HWMON driver

Added driver to support the 14F021P00 BMC Hardware Monitoring.
The BMC is a Board Management Controller including monitoring of the
board voltages.

Signed-off-by: Andreas Werner <andreas.werner@men.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/hwmon/menf21bmc

@@ -0,0 +1,50 @@
+Kernel driver menf21bmc_hwmon
+=============================
+
+Supported chips:
+	* MEN 14F021P00
+	  Prefix: 'menf21bmc_hwmon'
+	  Adresses scanned: -
+
+Author: Andreas Werner <andreas.werner@men.de>
+
+Description
+-----------
+
+The menf21bmc is a Board Management Controller (BMC) which provides an I2C
+interface to the host to access the features implemented in the BMC.
+
+This driver gives access to the voltage monitoring feature of the main
+voltages of the board.
+The voltage sensors are connected to the ADC inputs of the BMC which is
+a PIC16F917 Mikrocontroller.
+
+Usage Notes
+-----------
+
+This driver is part of the MFD driver named "menf21bmc" and does
+not auto-detect devices.
+You will have to instantiate the MFD driver explicitly.
+Please see Documentation/i2c/instantiating-devices for
+details.
+
+Sysfs entries
+-------------
+
+The following attributes are supported. All attributes are read only
+The Limits are read once by the driver.
+
+in0_input	+3.3V input voltage
+in1_input	+5.0V input voltage
+in2_input	+12.0V input voltage
+in3_input	+5V Standby input voltage
+in4_input	VBAT (on board battery)
+
+in[0-4]_min	Minimum voltage limit
+in[0-4]_max	Maximum voltage limit
+
+in0_label	"MON_3_3V"
+in1_label	"MON_5V"
+in2_label	"MON_12V"
+in3_label	"5V_STANDBY"
+in4_label	"VBAT"