power: Add a regulator driver for the as3722 PMIC

This pmic includes regulators which should have their own driver. Add
a driver to support these.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Tested-on: Beaver, Jetson-TK1
Tested-by: Stephen Warren <swarren@nvidia.com>
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index f213487..c82a936 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -34,6 +34,15 @@
 	by the PMIC device. This driver is controlled by a device tree node
 	which includes voltage limits.
 
+config REGULATOR_AS3722
+	bool "Enable driver for AS7322 regulator"
+	depends on DM_REGULATOR && PMIC_AS3722
+	help
+	  Enable support for the regulator functions of the AS3722. The
+	  driver implements enable/disable for step-down bucks and LDOs,
+	  but does not yet support change voltages. Currently this must be
+	  done using direct register writes to the PMIC.
+
 config DM_REGULATOR_PFUZE100
 	bool "Enable Driver Model for REGULATOR PFUZE100"
 	depends on DM_REGULATOR && DM_PMIC_PFUZE100