dt-bindings: add BCM6328 GPIO sysctl binding documentation

Add binding documentation for the GPIO sysctl found in BCM6328 SoCs.
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210324081923.20379-7-noltari@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/mfd/brcm,bcm6328-gpio-sysctl.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/brcm,bcm6328-gpio-sysctl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom BCM6328 GPIO System Controller Device Tree Bindings
+
+maintainers:
+  - Álvaro Fernández Rojas <noltari@gmail.com>
+  - Jonas Gorski <jonas.gorski@gmail.com>
+
+description:
+  Broadcom BCM6328 SoC GPIO system controller which provides a register map
+  for controlling the GPIO and pins of the SoC.
+
+properties:
+  "#address-cells": true
+
+  "#size-cells": true
+
+  compatible:
+    items:
+      - const: brcm,bcm6328-gpio-sysctl
+      - const: syscon
+      - const: simple-mfd
+
+  ranges:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  "^gpio@[0-9a-f]+$":
+    # Child node
+    type: object
+    $ref: "../gpio/brcm,bcm6345-gpio.yaml"
+    description:
+      GPIO controller for the SoC GPIOs. This child node definition
+      should follow the bindings specified in
+      Documentation/devicetree/bindings/gpio/brcm,bcm6345-gpio.yaml.
+
+  "^pinctrl@[0-9a-f]+$":
+    # Child node
+    type: object
+    $ref: "../pinctrl/brcm,bcm6328-pinctrl.yaml"
+    description:
+      Pin controller for the SoC pins. This child node definition
+      should follow the bindings specified in
+      Documentation/devicetree/bindings/pinctrl/brcm,bcm6328-pinctrl.yaml.
+
+required:
+  - "#address-cells"
+  - compatible
+  - ranges
+  - reg
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    syscon@10000080 {
+      #address-cells = <1>;
+      #size-cells = <1>;
+      compatible = "brcm,bcm6328-gpio-sysctl", "syscon", "simple-mfd";
+      reg = <0x10000080 0x80>;
+      ranges = <0 0x10000080 0x80>;
+
+      gpio@0 {
+        compatible = "brcm,bcm6328-gpio";
+        reg-names = "dirout", "dat";
+        reg = <0x0 0x8>, <0x8 0x8>;
+
+        gpio-controller;
+        gpio-ranges = <&pinctrl 0 0 32>;
+        #gpio-cells = <2>;
+      };
+
+      pinctrl: pinctrl@18 {
+        compatible = "brcm,bcm6328-pinctrl";
+        reg = <0x18 0x10>;
+
+        pinctrl_serial_led: serial_led-pins {
+          pinctrl_serial_led_data: serial_led_data-pins {
+            function = "serial_led_data";
+            pins = "gpio6";
+          };
+
+          pinctrl_serial_led_clk: serial_led_clk-pins {
+            function = "serial_led_clk";
+            pins = "gpio7";
+          };
+        };
+
+        pinctrl_inet_act_led: inet_act_led-pins {
+          function = "inet_act_led";
+          pins = "gpio11";
+        };
+
+        pinctrl_pcie_clkreq: pcie_clkreq-pins {
+          function = "pcie_clkreq";
+          pins = "gpio16";
+        };
+
+        pinctrl_ephy0_spd_led: ephy0_spd_led-pins {
+          function = "led";
+          pins = "gpio17";
+        };
+
+        pinctrl_ephy1_spd_led: ephy1_spd_led-pins {
+          function = "led";
+          pins = "gpio18";
+        };
+
+        pinctrl_ephy2_spd_led: ephy2_spd_led-pins {
+          function = "led";
+          pins = "gpio19";
+        };
+
+        pinctrl_ephy3_spd_led: ephy3_spd_led-pins {
+          function = "led";
+          pins = "gpio20";
+        };
+
+        pinctrl_ephy0_act_led: ephy0_act_led-pins {
+          function = "ephy0_act_led";
+          pins = "gpio25";
+        };
+
+        pinctrl_ephy1_act_led: ephy1_act_led-pins {
+          function = "ephy1_act_led";
+          pins = "gpio26";
+        };
+
+        pinctrl_ephy2_act_led: ephy2_act_led-pins {
+          function = "ephy2_act_led";
+          pins = "gpio27";
+        };
+
+        pinctrl_ephy3_act_led: ephy3_act_led-pins {
+          function = "ephy3_act_led";
+          pins = "gpio28";
+        };
+
+        pinctrl_hsspi_cs1: hsspi_cs1-pins {
+          function = "hsspi_cs1";
+          pins = "hsspi_cs1";
+        };
+
+        pinctrl_usb_port1_device: usb_port1_device-pins {
+          function = "usb_device_port";
+          pins = "usb_port1";
+        };
+
+        pinctrl_usb_port1_host: usb_port1_host-pins {
+          function = "usb_host_port";
+          pins = "usb_port1";
+        };
+      };
+    };