dt-bindings: arm: airoha: Add binding for Airoha GPIO controller

Airoha's GPIO controller on their ARM EN7523 SoCs consists of two banks of 32
GPIOs
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: John Crispin <john@phrozen.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
[Bartosz: removed stray newline at the end of the file]
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Documentation/devicetree/bindings/gpio/airoha,en7523-gpio.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/airoha,en7523-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Airoha EN7523 GPIO controller
+
+maintainers:
+  - John Crispin <john@phrozen.org>
+
+description: |
+  Airoha's GPIO controller on their ARM EN7523 SoCs consists of two banks of 32
+  GPIOs.
+
+properties:
+  $nodename:
+    pattern: "^gpio@[0-9a-f]+$"
+
+  compatible:
+    items:
+      - const: airoha,en7523-gpio
+
+  reg:
+    description: |
+      The first tuple points to the input register.
+      The second and third tuple point to the direction registers
+      The fourth tuple points to the output register
+    maxItems: 4
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-controller: true
+
+required:
+  - compatible
+  - reg
+  - "#gpio-cells"
+  - gpio-controller
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio0: gpio@1fbf0200 {
+        compatible = "airoha,en7523-gpio";
+        reg = <0x1fbf0204 0x4>,
+              <0x1fbf0200 0x4>,
+              <0x1fbf0220 0x4>,
+              <0x1fbf0214 0x4>;
+        gpio-controller;
+        #gpio-cells = <2>;
+    };
+
+    gpio1: gpio@1fbf0270 {
+        compatible = "airoha,en7523-gpio";
+        reg = <0x1fbf0270 0x4>,
+              <0x1fbf0260 0x4>,
+              <0x1fbf0264 0x4>,
+              <0x1fbf0278 0x4>;
+        gpio-controller;
+        #gpio-cells = <2>;
+    };
+
+...