dt-bindings: soc: renesas: Add RZ/V2M PWC

The Renesas RZ/V2M External Power Sequence Controller (PWC) IP
is capable of:
* external power supply on/off sequence generation
* on/off signal generation for the LPDDR4 core power supply (LPVDD)
* key input signals processing
* general-purpose output pins

Add the corresponding dt-bindings.

Signed-off-by: Fabrizio Castro <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

Documentation/devicetree/bindings/soc/renesas/renesas,rzv2m-pwc.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/renesas/renesas,rzv2m-pwc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/V2M External Power Sequence Controller (PWC)
+
+description: |+
+  The PWC IP found in the RZ/V2M family of chips comes with the below
+  capabilities
+    - external power supply on/off sequence generation
+    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
+    - key input signals processing
+    - general-purpose output pins
+
+maintainers:
+  - Fabrizio Castro <[e-mail]>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r9a09g011-pwc # RZ/V2M
+          - renesas,r9a09g055-pwc # RZ/V2MA
+      - const: renesas,rzv2m-pwc
+
+  reg:
+    maxItems: 1
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+  renesas,rzv2m-pwc-power:
+    description: The PWC is used to control the system power supplies.
+    type: boolean
+
+required:
+  - compatible
+  - reg
+  - gpio-controller
+  - '#gpio-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    pwc: pwc@a3700000 {
+      compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc";
+      reg = <0xa3700000 0x800>;
+      gpio-controller;
+      #gpio-cells = <2>;
+      renesas,rzv2m-pwc-power;
+    };