dt-bindings: regulator: add DT bindings for UniPhier regulator

Socionext UniPhier Regulator Controller

This describes the devicetree bindings for regulator controller implemented

on Socionext UniPhier SoCs.

USB3 Controller

---------------

This regulator controls VBUS and belongs to USB3 glue layer. Before using

the regulator, it is necessary to control the clocks and resets to enable

this layer. These clocks and resets should be described in each property.

Required properties:

- compatible: Should be

    "socionext,uniphier-pro4-usb3-regulator" - for Pro4 SoC

    "socionext,uniphier-pxs2-usb3-regulator" - for PXs2 SoC

    "socionext,uniphier-ld20-usb3-regulator" - for LD20 SoC

    "socionext,uniphier-pxs3-usb3-regulator" - for PXs3 SoC

- reg: Specifies offset and length of the register set for the device.

- clocks: A list of phandles to the clock gate for USB3 glue layer.

	According to the clock-names, appropriate clocks are required.

- clock-names: Should contain

    "gio", "link" - for Pro4 SoC

    "link"        - for others

- resets: A list of phandles to the reset control for USB3 glue layer.

	According to the reset-names, appropriate resets are required.

- reset-names: Should contain

    "gio", "link" - for Pro4 SoC

    "link"        - for others

See Documentation/devicetree/bindings/regulator/regulator.txt

for more details about the regulator properties.

Example:

	usb-glue@65b00000 {

		compatible = "socionext,uniphier-ld20-dwc3-glue",

			     "simple-mfd";

		#address-cells = <1>;

		#size-cells = <1>;

		ranges = <0 0x65b00000 0x400>;

		usb_vbus0: regulators@100 {

			compatible = "socionext,uniphier-ld20-usb3-regulator";

			reg = <0x100 0x10>;

			clock-names = "link";

			clocks = <&sys_clk 14>;

			reset-names = "link";

			resets = <&sys_rst 14>;

		};

		phy {

			...

			phy-supply = <&usb_vbus0>;

		};

		...

	};