dt-bindings: improve BCM6345 GPIO binding documentation

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;

	};

# 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>;

    };