dt-bindings: pinctrl: mt8192: add binding document

The commit adds mt8192 compatible node in binding document.
Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200817001702.1646-3-zhiyong.tao@mediatek.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-mt8192.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/pinctrl-mt8192.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mediatek MT8192 Pin Controller
+
+maintainers:
+  - Sean Wang <sean.wang@mediatek.com>
+
+description: |
+  The Mediatek's Pin controller is used to control SoC pins.
+
+properties:
+  compatible:
+    const: mediatek,mt8192-pinctrl
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    description: |
+      Number of cells in GPIO specifier. Since the generic GPIO binding is used,
+      the amount of cells must be specified as 2. See the below
+      mentioned gpio binding representation for description of particular cells.
+    const: 2
+
+  gpio-ranges:
+    description: gpio valid number range.
+    maxItems: 1
+
+  reg:
+    description: |
+      Physical address base for gpio base registers. There are 11 GPIO
+      physical address base in mt8192.
+    maxItems: 11
+
+  reg-names:
+    description: |
+      Gpio base register names.
+    maxItems: 11
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+  interrupts:
+    description: The interrupt outputs to sysirq.
+    maxItems: 1
+
+#PIN CONFIGURATION NODES
+patternProperties:
+  '^pins':
+    type: object
+    description: |
+      A pinctrl node should contain at least one subnodes representing the
+      pinctrl groups available on the machine. Each subnode will list the
+      pins it needs, and how they should be configured, with regard to muxer
+      configuration, pullups, drive strength, input enable/disable and
+      input schmitt.
+      An example of using macro:
+      pincontroller {
+        /* GPIO0 set as multifunction GPIO0 */
+        state_0_node_a {
+          pinmux = <PINMUX_GPIO0__FUNC_GPIO0>;
+        };
+        /* GPIO1 set as multifunction PWM */
+        state_0_node_b {
+          pinmux = <PINMUX_GPIO1__FUNC_PWM_1>;
+        };
+      };
+    $ref: "pinmux-node.yaml"
+
+    properties:
+      pinmux:
+        description: |
+          Integer array, represents gpio pin number and mux setting.
+          Supported pin number and mux varies for different SoCs, and are defined
+          as macros in dt-bindings/pinctrl/<soc>-pinfunc.h directly.
+
+      drive-strength:
+        description: |
+          It can support some arguments, such as MTK_DRIVE_4mA, MTK_DRIVE_6mA, etc. See
+          dt-bindings/pinctrl/mt65xx.h. It can only support 2/4/6/8/10/12/14/16mA in mt8192.
+        enum: [2, 4, 6, 8, 10, 12, 14, 16]
+
+      bias-pull-down: true
+
+      bias-pull-up: true
+
+      bias-disable: true
+
+      output-high: true
+
+      output-low: true
+
+      input-enable: true
+
+      input-disable: true
+
+      input-schmitt-enable: true
+
+      input-schmitt-disable: true
+
+    required:
+      - pinmux
+
+    additionalProperties:  false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - '#interrupt-cells'
+  - gpio-controller
+  - '#gpio-cells'
+  - gpio-ranges
+
+additionalProperties: false
+
+examples:
+  - |
+            #include <dt-bindings/pinctrl/mt8192-pinfunc.h>
+            #include <dt-bindings/interrupt-controller/arm-gic.h>
+            pio: pinctrl@10005000 {
+                    compatible = "mediatek,mt8192-pinctrl";
+                    reg = <0x10005000 0x1000>,
+                          <0x11c20000 0x1000>,
+                          <0x11d10000 0x1000>,
+                          <0x11d30000 0x1000>,
+                          <0x11d40000 0x1000>,
+                          <0x11e20000 0x1000>,
+                          <0x11e70000 0x1000>,
+                          <0x11ea0000 0x1000>,
+                          <0x11f20000 0x1000>,
+                          <0x11f30000 0x1000>,
+                          <0x1000b000 0x1000>;
+                    reg-names = "iocfg0", "iocfg_rm", "iocfg_bm",
+                          "iocfg_bl", "iocfg_br", "iocfg_lm",
+                          "iocfg_lb", "iocfg_rt", "iocfg_lt",
+                          "iocfg_tl", "eint";
+                    gpio-controller;
+                    #gpio-cells = <2>;
+                    gpio-ranges = <&pio 0 0 220>;
+                    interrupt-controller;
+                    interrupts = <GIC_SPI 212 IRQ_TYPE_LEVEL_HIGH 0>;
+                    #interrupt-cells = <2>;
+
+                    pins {
+                      pinmux = <PINMUX_GPIO0__FUNC_GPIO0>;
+                      output-low;
+                    };
+            };