clk: shmobile: r8a7779: Add CPG/MSTP Clock Domain support

Add Clock Domain support to the R-Car H1 Clock Pulse Generator (CPG)
driver using the generic PM Domain.  This allows to power-manage the
module clocks of SoC devices that are part of the CPG/MSTP Clock Domain
using Runtime PM, or for system suspend/resume.

SoC devices that are part of the CPG/MSTP Clock Domain and can be
power-managed through an MSTP clock should be tagged in DT with a proper
"power-domains" property.

Also update the reg property in the DT binding doc example to match the
actual dtsi, which uses #address-cells and #size-cells == 1, not 2.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/clock/renesas,r8a7779-cpg-clocks.txt

@@ -1,7 +1,9 @@
 * Renesas R8A7779 Clock Pulse Generator (CPG)
 
 The CPG generates core clocks for the R8A7779. It includes one PLL and
-several fixed ratio dividers
+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:
 
@@ -12,16 +14,36 @@ Required Properties:
   - #clock-cells: Must be 1
   - clock-output-names: The names of the clocks. Supported clocks are "plla",
     "z", "zs", "s", "s1", "p", "b", "out".
+  - #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@ffc80000 {
 		compatible = "renesas,r8a7779-cpg-clocks";
-		reg = <0 0xffc80000 0 0x30>;
+		reg = <0xffc80000 0x30>;
 		clocks = <&extal_clk>;
 		#clock-cells = <1>;
 		clock-output-names = "plla", "z", "zs", "s", "s1", "p",
 		                     "b", "out";
+		#power-domain-cells = <0>;
+	};
+
+
+  - CPG/MSTP Clock Domain member device node:
+
+	sata: sata@fc600000 {
+		compatible = "renesas,sata-r8a7779", "renesas,rcar-sata";
+		reg = <0xfc600000 0x2000>;
+		interrupts = <0 100 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&mstp1_clks R8A7779_CLK_SATA>;
+		power-domains = <&cpg_clocks>;
 	};

drivers/clk/shmobile/clk-r8a7779.c

@@ -168,6 +168,8 @@ static void __init r8a7779_cpg_clocks_init(struct device_node *np)
 	}
 
 	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
+
+	cpg_mstp_add_clk_domain(np);
 }
 CLK_OF_DECLARE(r8a7779_cpg_clks, "renesas,r8a7779-cpg-clocks",
 	       r8a7779_cpg_clocks_init);