regulator: Add WM831x DC-DC buck convertor support

The WM831x series of devices all have 3 DC-DC buck convertors. This
driver implements software control for these regulators via the
regulator API.  Use with split hardware/software control of individual
regulators is not supported, though regulators not controlled by
software may be controlled via the hardware control interfaces.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/regulator/Kconfig

@@ -82,6 +82,13 @@ config REGULATOR_TWL4030
 	  This driver supports the voltage regulators provided by
 	  this family of companion chips.
 
+config REGULATOR_WM831X
+	tristate "Wolfson Microelcronics WM831x PMIC regulators"
+	depends on MFD_WM831X
+	help
+	  Support the voltage and current regulators of the WM831x series
+	  of PMIC devices.
+
 config REGULATOR_WM8350
 	tristate "Wolfson Microelectroncis WM8350 AudioPlus PMIC"
 	depends on MFD_WM8350

drivers/regulator/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_REGULATOR_BQ24022) += bq24022.o
 obj-$(CONFIG_REGULATOR_LP3971) += lp3971.o
 obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o
 obj-$(CONFIG_REGULATOR_TWL4030) += twl4030-regulator.o
+obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o
 obj-$(CONFIG_REGULATOR_WM8350) += wm8350-regulator.o
 obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
 obj-$(CONFIG_REGULATOR_DA903X)	+= da903x.o