regulator: lp873x: Add support for populating input supply

In order to have a proper topology of regulators for a platform, each
registering regulator needs to populate supply_name field for identifying
its supply's name. Add supply_name field for lp873x regulators.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/mfd/lp873x.txt

@@ -7,6 +7,9 @@ Required properties:
   - #gpio-cells:	Should be two.  The first cell is the pin number and
 			the second cell is used to specify flags.
 			See ../gpio/gpio.txt for more information.
+  - xxx-in-supply:	Phandle to parent supply node of each regulator
+			populated under regulators node. xxx can be
+			buck0, buck1, ldo0 or ldo1.
   - regulators:	List of child nodes that specify the regulator
 			initialization data.
 Example:
@@ -17,6 +20,11 @@ pmic: lp8733@60 {
 	gpio-controller;
 	#gpio-cells = <2>;
 
+	buck0-in-supply = <&vsys_3v3>;
+	buck1-in-supply = <&vsys_3v3>;
+	ldo0-in-supply = <&vsys_3v3>;
+	ldo1-in-supply = <&vsys_3v3>;
+
 	regulators {
 		lp8733_buck0: buck0 {
 			regulator-name = "lp8733-buck0";