dt-bindings: power: apmu: Convert to json-schema

Convert the Renesas Advanced Power Management Unit Device Tree binding
documentation to json-schema.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/power/renesas,apmu.txt

-DT bindings for the Renesas Advanced Power Management Unit
-
-Renesas R-Car and RZ/G1 SoCs utilize one or more APMU hardware units
-for CPU core power domain control including SMP boot and CPU Hotplug.
-
-Required properties:
-
-- compatible: Should be "renesas,<soctype>-apmu", "renesas,apmu" as fallback.
-	      Examples with soctypes are:
-		- "renesas,r8a7743-apmu" (RZ/G1M)
-		- "renesas,r8a7744-apmu" (RZ/G1N)
-		- "renesas,r8a7745-apmu" (RZ/G1E)
-		- "renesas,r8a77470-apmu" (RZ/G1C)
-		- "renesas,r8a7790-apmu" (R-Car H2)
-		- "renesas,r8a7791-apmu" (R-Car M2-W)
-		- "renesas,r8a7792-apmu" (R-Car V2H)
-		- "renesas,r8a7793-apmu" (R-Car M2-N)
-		- "renesas,r8a7794-apmu" (R-Car E2)
-
-- reg: Base address and length of the I/O registers used by the APMU.
-
-- cpus: This node contains a list of CPU cores, which should match the order
-  of CPU cores used by the WUPCR and PSTR registers in the Advanced Power
-  Management Unit section of the device's datasheet.
-
-
-Example:
-
-This shows the r8a7791 APMU that can control CPU0 and CPU1.
-
-	apmu@e6152000 {
-		compatible = "renesas,r8a7791-apmu", "renesas,apmu";
-		reg = <0 0xe6152000 0 0x188>;
-		cpus = <&cpu0 &cpu1>;
-	};

Documentation/devicetree/bindings/power/renesas,apmu.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/power/renesas,apmu.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Renesas Advanced Power Management Unit
+
+maintainers:
+  - Geert Uytterhoeven <geert+renesas@glider.be>
+  - Magnus Damm <magnus.damm@gmail.com>
+
+description:
+  Renesas R-Car Gen2 and RZ/G1 SoCs utilize one or more APMU hardware units for
+  CPU core power domain control including SMP boot and CPU Hotplug.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r8a7743-apmu  # RZ/G1M
+          - renesas,r8a7744-apmu  # RZ/G1N
+          - renesas,r8a7745-apmu  # RZ/G1E
+          - renesas,r8a77470-apmu # RZ/G1C
+          - renesas,r8a7790-apmu  # R-Car H2
+          - renesas,r8a7791-apmu  # R-Car M2-W
+          - renesas,r8a7792-apmu  # R-Car V2H
+          - renesas,r8a7793-apmu  # R-Car M2-N
+          - renesas,r8a7794-apmu  # R-Car E2
+      - const: renesas,apmu
+
+  reg:
+    maxItems: 1
+
+  cpus:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: |
+      Array of phandles pointing to CPU cores, which should match the order of
+      CPU cores used by the WUPCR and PSTR registers in the Advanced Power
+      Management Unit section of the device's datasheet.
+
+required:
+  - compatible
+  - reg
+  - cpus
+
+additionalProperties: false
+
+examples:
+  - |
+    apmu@e6152000 {
+            compatible = "renesas,r8a7791-apmu", "renesas,apmu";
+            reg = <0xe6152000 0x188>;
+            cpus = <&cpu0 &cpu1>;
+    };