dt-bindings: pinctrl: mt8195: add pinctrl file and binding document

1. This patch adds pinctrl file for mt8195.
2. This patch adds mt8195 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/20210413055702.27535-2-zhiyong.tao@mediatek.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-mt8195.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/pinctrl-mt8195.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Mediatek MT8195 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,mt8195-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 8 GPIO
+      physical address base in mt8195.
+    maxItems: 8
+
+  reg-names:
+    description: |
+      Gpio base register names.
+    maxItems: 8
+
+  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 */
+        gpio_pin {
+          pinmux = <PINMUX_GPIO0__FUNC_GPIO0>;
+        };
+        /* GPIO8 set as multifunction SDA0 */
+        i2c0_pin {
+          pinmux = <PINMUX_GPIO8__FUNC_SDA0>;
+        };
+      };
+    $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 which is from 0 to 7. It can only support
+          2/4/6/8/10/12/14/16mA in mt8195.
+        enum: [0, 1, 2, 3, 4, 5, 6, 7]
+
+      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/mt8195-pinfunc.h>
+            #include <dt-bindings/interrupt-controller/arm-gic.h>
+            pio: pinctrl@10005000 {
+                    compatible = "mediatek,mt8195-pinctrl";
+                    reg = <0x10005000 0x1000>,
+                          <0x11d10000 0x1000>,
+                          <0x11d30000 0x1000>,
+                          <0x11d40000 0x1000>,
+                          <0x11e20000 0x1000>,
+                          <0x11eb0000 0x1000>,
+                          <0x11f40000 0x1000>,
+                          <0x1000b000 0x1000>;
+                    reg-names = "iocfg0", "iocfg_bm", "iocfg_bl",
+                          "iocfg_br", "iocfg_lm", "iocfg_rb",
+                          "iocfg_tl", "eint";
+                    gpio-controller;
+                    #gpio-cells = <2>;
+                    gpio-ranges = <&pio 0 0 144>;
+                    interrupt-controller;
+                    interrupts = <GIC_SPI 225 IRQ_TYPE_LEVEL_HIGH 0>;
+                    #interrupt-cells = <2>;
+
+                    pio-pins {
+                      pinmux = <PINMUX_GPIO0__FUNC_GPIO0>;
+                      output-low;
+                    };
+            };