hwmon: WM831x PMIC hardware monitoring driver

This driver adds support for the hardware monitoring features of
the WM831x PMICs to the hwmon API. Monitoring is provided for
the system voltages supported natively by the WM831x, the chip
temperature, the battery temperature and the auxiliary inputs
of the WM831x.

Currently no alarms are supported, though digital comparators on
the WM831x devices would allow these to be provided.

Since the auxiliary and battery temperature input scaling depends
on the system configuration the value is reported as a voltage to
userspace.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 120085c..83e07e5 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -937,6 +937,17 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called w83627ehf.
 
+config SENSORS_WM831X
+	tristate "WM831x PMICs"
+	depends on MFD_WM831X
+	help
+	  If you say yes here you get support for the hardware
+	  monitoring functionality of the Wolfson Microelectronics
+	  WM831x series of PMICs.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called wm831x-hwmon.
+
 config SENSORS_WM8350
 	tristate "Wolfson Microelectronics WM835x"
 	depends on MFD_WM8350