power_supply: Add driver for the PMU on WM831x PMICs

The WM831x PMICs provide power path management from three sources:
a wall supply, USB and a battery with integrated charger. They also
provide an additional backup supply with integrated for maintaining
always on functionality such as the RTC and monitoring of power
switches.

After some initial configuration at startup the device operates
autonomously, the driver simply provides reporting of the current
state.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>

drivers/power/Kconfig

@@ -29,6 +29,13 @@ config APM_POWER
 	  Say Y here to enable support APM status emulation using
 	  battery class devices.
 
+config WM831X_POWER
+	tristate "WM831X PMU support"
+	depends on MFD_WM831X
+	help
+	  Say Y here to enable support for the power management unit
+	  provided by Wolfson Microelectronics WM831x PMICs.
+
 config WM8350_POWER
         tristate "WM8350 PMU support"
         depends on MFD_WM8350

drivers/power/Makefile

@@ -16,6 +16,7 @@ obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
 
 obj-$(CONFIG_PDA_POWER)		+= pda_power.o
 obj-$(CONFIG_APM_POWER)		+= apm_power.o
+obj-$(CONFIG_WM831X_POWER)	+= wm831x_power.o
 obj-$(CONFIG_WM8350_POWER)	+= wm8350_power.o
 
 obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o