dt-bindings: improve BCM6345 GPIO binding documentation

Convert existing BCM6345 GPIO binding documentation to YAML and add binding
documentation for the GPIO controller found in BCM6318, BCM6328, BCM6358,
BCM6362, BCM6368 and BCM63268 SoCs.
Co-developed-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210324081923.20379-4-noltari@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/brcm,bcm6345-gpio.txt

-Bindings for the Broadcom's brcm,bcm6345-gpio memory-mapped GPIO controllers.
-
-These bindings can be used on any BCM63xx SoC. However, BCM6338 and BCM6345
-are the only ones which don't need a pinctrl driver.
-BCM6338 have 8-bit data and dirout registers, where GPIO state can be read
-and/or written, and the direction changed from input to output.
-BCM6345 have 16-bit data and dirout registers, where GPIO state can be read
-and/or written, and the direction changed from input to output.
-
-Required properties:
-	- compatible: should be "brcm,bcm6345-gpio"
-	- reg-names: must contain
-		"dat" - data register
-		"dirout" - direction (output) register
-	- reg: address + size pairs describing the GPIO register sets;
-		order must correspond with the order of entries in reg-names
-	- #gpio-cells: must be set to 2. The first cell is the pin number and
-			the second cell is used to specify the gpio polarity:
-			0 = active high
-			1 = active low
-	- gpio-controller: Marks the device node as a gpio controller.
-
-Optional properties:
-	- native-endian: use native endian memory.
-
-Examples:
-	- BCM6338:
-	gpio: gpio-controller@fffe0407 {
-		compatible = "brcm,bcm6345-gpio";
-		reg-names = "dirout", "dat";
-		reg = <0xfffe0407 1>, <0xfffe040f 1>;
-
-		#gpio-cells = <2>;
-		gpio-controller;
-	};
-
-	- BCM6345:
-	gpio: gpio-controller@fffe0406 {
-		compatible = "brcm,bcm6345-gpio";
-		reg-names = "dirout", "dat";
-		reg = <0xfffe0406 2>, <0xfffe040a 2>;
-		native-endian;
-
-		#gpio-cells = <2>;
-		gpio-controller;
-	};

Documentation/devicetree/bindings/gpio/brcm,bcm6345-gpio.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/brcm,bcm6345-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom BCM6345 GPIO controller
+
+maintainers:
+  - Álvaro Fernández Rojas <noltari@gmail.com>
+  - Jonas Gorski <jonas.gorski@gmail.com>
+
+description: |+
+  Bindings for Broadcom's BCM63xx memory-mapped GPIO controllers.
+
+  These bindings can be used on any BCM63xx SoC. However, BCM6338 and BCM6345
+  are the only ones which don't need a pinctrl driver.
+
+  BCM6338 have 8-bit data and dirout registers, where GPIO state can be read
+  and/or written, and the direction changed from input to output.
+  BCM6345 have 16-bit data and dirout registers, where GPIO state can be read
+  and/or written, and the direction changed from input to output.
+  BCM6318, BCM6328, BCM6358, BCM6362, BCM6368 and BCM63268 have 32-bit data
+  and dirout registers, where GPIO state can be read and/or written, and the
+  direction changed from input to output.
+
+properties:
+  compatible:
+    enum:
+      - brcm,bcm6318-gpio
+      - brcm,bcm6328-gpio
+      - brcm,bcm6345-gpio
+      - brcm,bcm6358-gpio
+      - brcm,bcm6362-gpio
+      - brcm,bcm6368-gpio
+      - brcm,bcm63268-gpio
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-ranges:
+    maxItems: 1
+
+  native-endian: true
+
+  reg:
+    maxItems: 2
+
+  reg-names:
+    items:
+      - const: dirout
+      - const: dat
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - gpio-controller
+  - '#gpio-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio@fffe0406 {
+      compatible = "brcm,bcm6345-gpio";
+      reg-names = "dirout", "dat";
+      reg = <0xfffe0406 2>, <0xfffe040a 2>;
+      native-endian;
+
+      gpio-controller;
+      #gpio-cells = <2>;
+    };
+
+  - |
+    gpio@0 {
+      compatible = "brcm,bcm63268-gpio";
+      reg-names = "dirout", "dat";
+      reg = <0x0 0x8>, <0x8 0x8>;
+
+      gpio-controller;
+      gpio-ranges = <&pinctrl 0 0 52>;
+      #gpio-cells = <2>;
+    };