PM / Domains: Add DT bindings for the R-Mobile System Controller

DT bindings for the Renesas R-Mobile System Controller

== System Controller Node ==

The R-Mobile System Controller provides the following functions:

  - Boot mode management,

  - Reset generation,

  - Power management.

Required properties:

- compatible: Should be "renesas,sysc-<soctype>", "renesas,sysc-rmobile" as

	      fallback.

	      Examples with soctypes are:

		- "renesas,sysc-r8a7740" (R-Mobile A1)

- reg: Two address start and address range blocks for the device:

         - The first block refers to the normally accessible registers,

         - the second block refers to the registers protected by the HPB

	   semaphore.

Optional nodes:

- pm-domains: This node contains a hierarchy of PM domain nodes, which should

  match the Power Area Hierarchy in the Power Domain Specifications section of

  the device's datasheet.

== PM Domain Nodes ==

Each of the PM domain nodes represents a PM domain, as documented by the

generic PM domain bindings in

Documentation/devicetree/bindings/power/power_domain.txt.

The nodes should be named by the real power area names, and thus their names

should be unique.

Required properties:

  - #power-domain-cells: Must be 0.

Optional properties:

- reg: If the PM domain is not always-on, this property must contain the bit

       index number for the corresponding power area in the various Power

       Control and Status Registers. The parent's node must contain the

       following two properties:

	 - #address-cells: Must be 1,

	 - #size-cells: Must be 0.

       If the PM domain is always-on, this property must be omitted.

Example:

This shows a subset of the r8a7740 PM domain hierarchy, containing the

C5 "always-on" domain, 2 of its subdomains (A4S and A4SU), and the A3SP domain,

which is a subdomain of A4S.

	sysc: system-controller@e6180000 {

		compatible = "renesas,sysc-r8a7740", "renesas,sysc-rmobile";

		reg = <0xe6180000 0x8000>, <0xe6188000 0x8000>;

		pm-domains {

			pd_c5: c5 {

				#address-cells = <1>;

				#size-cells = <0>;

				#power-domain-cells = <0>;

				pd_a4s: a4s@10 {

					reg = <10>;

					#address-cells = <1>;

					#size-cells = <0>;

					#power-domain-cells = <0>;

					pd_a3sp: a3sp@11 {

						reg = <11>;

						#power-domain-cells = <0>;

					};

				};

				pd_a4su: a4su@20 {

					reg = <20>;

					#power-domain-cells = <0>;

				};

			};

		};

	};

== PM Domain Consumers ==

Hardware blocks belonging to a PM domain should contain a "power-domains"

property that is a phandle pointing to the corresponding PM domain node.

Example:

	tpu: pwm@e6600000 {

		compatible = "renesas,tpu-r8a7740", "renesas,tpu";

		reg = <0xe6600000 0x100>;

		clocks = <&mstp3_clks R8A7740_CLK_TPU0>;

		power-domains = <&pd_a3sp>;

		#pwm-cells = <3>;

	};