clk: shmobile: rcar-gen2: Add CPG/MSTP Clock Domain support

The CPG generates core clocks for the R-Car Gen2 SoCs. It includes three PLLs

and several fixed ratio dividers.

The CPG also provides a Clock Domain for SoC devices, in combination with the

CPG Module Stop (MSTP) Clocks.

Required Properties:

  - clock-output-names: The names of the clocks. Supported clocks are "main",

    "pll0", "pll1", "pll3", "lb", "qspi", "sdh", "sd0", "sd1", "z", "rcan", and

    "adsp"

  - #power-domain-cells: Must be 0

SoC devices that are part of the CPG/MSTP Clock Domain and can be power-managed

through an MSTP clock should refer to the CPG device node in their

"power-domains" property, as documented by the generic PM domain bindings in

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

Example

-------

Examples

--------

  - CPG device node:

	cpg_clocks: cpg_clocks@e6150000 {

		compatible = "renesas,r8a7790-cpg-clocks",

		clock-output-names = "main", "pll0, "pll1", "pll3",

				     "lb", "qspi", "sdh", "sd0", "sd1", "z",

				     "rcan", "adsp";

		#power-domain-cells = <0>;

	};

  - CPG/MSTP Clock Domain member device node:

	thermal@e61f0000 {

		compatible = "renesas,thermal-r8a7790", "renesas,rcar-thermal";

		reg = <0 0xe61f0000 0 0x14>, <0 0xe61f0100 0 0x38>;

		interrupts = <0 69 IRQ_TYPE_LEVEL_HIGH>;

		clocks = <&mstp5_clks R8A7790_CLK_THERMAL>;

		power-domains = <&cpg_clocks>;

	};

	}

	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);

	cpg_mstp_add_clk_domain(np);

}

CLK_OF_DECLARE(rcar_gen2_cpg_clks, "renesas,rcar-gen2-cpg-clocks",

	       rcar_gen2_cpg_clocks_init);