dt-bindings: pinctrl: mediatek: Document MT6878 pin controller bindings

Add device-tree bindings for the pin controller and the EINT controller
found in the MediaTek MT6878 SoC.

Signed-off-by: Igor Belwon <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/pinctrl/mediatek,mt6878-pinctrl.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/mediatek,mt6878-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek MT6878 Pin Controller
+
+maintainers:
+  - AngeloGioacchino Del Regno <[e-mail]>
+  - Igor Belwon <[e-mail]>
+
+description:
+  The MediaTek MT6878 Pin controller is used to control SoC pins.
+
+properties:
+  compatible:
+    const: mediatek,mt6878-pinctrl
+
+  reg:
+    items:
+      - description: pin controller base
+      - description: bl group IO
+      - description: bm group IO
+      - description: br group IO
+      - description: bl1 group IO
+      - description: br1 group IO
+      - description: lm group IO
+      - description: lt group IO
+      - description: rm group IO
+      - description: rt group IO
+      - description: EINT controller E block
+      - description: EINT controller S block
+      - description: EINT controller W block
+      - description: EINT controller C block
+
+  reg-names:
+    items:
+      - const: base
+      - const: bl
+      - const: bm
+      - const: br
+      - const: bl1
+      - const: br1
+      - const: lm
+      - const: lt
+      - const: rm
+      - const: rt
+      - const: eint-e
+      - const: eint-s
+      - const: eint-w
+      - const: eint-c
+
+  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:
+    maxItems: 1
+
+  gpio-line-names:
+    maxItems: 216
+
+  interrupts:
+    description: The interrupt outputs to sysirq
+    maxItems: 1
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 2
+
+# PIN CONFIGURATION NODES
+patternProperties:
+  '-pins$':
+    type: object
+    additionalProperties: false
+
+    patternProperties:
+      '^pins':
+        type: object
+        allOf:
+          - $ref: /schemas/pinctrl/pincfg-node.yaml
+          - $ref: /schemas/pinctrl/pinmux-node.yaml
+        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.
+
+        properties:
+          pinmux:
+            description:
+              Integer array, represents gpio pin number and mux setting.
+              Supported pin number and mux are defined as macros in
+              arch/arm64/boot/dts/mediatek/mt8196-pinfunc.h for this SoC.
+
+          drive-strength:
+            enum: [2, 4, 6, 8, 10, 12, 14, 16]
+
+          drive-strength-microamp:
+            enum: [125, 250, 500, 1000]
+
+          bias-pull-down:
+            oneOf:
+              - type: boolean
+              - enum: [75000, 5000]
+                description: Pull down RSEL type resistance values (in ohms)
+            description:
+              For normal pull down type there is no need to specify a resistance
+              value, hence this can be specified as a boolean property.
+              For RSEL pull down type a resistance value (in ohms) can be added.
+
+          bias-pull-up:
+            oneOf:
+              - type: boolean
+              - enum: [10000, 5000, 4000, 3000]
+                description: Pull up RSEL type resistance values (in ohms)
+            description:
+              For normal pull up type there is no need to specify a resistance
+              value, hence this can be specified as a boolean property.
+              For RSEL pull up type a resistance value (in ohms) can be added.
+
+          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/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/pinctrl/mt65xx.h>
+    #define PINMUX_GPIO0__FUNC_GPIO0 (MTK_PIN_NO(0) | 0)
+    #define PINMUX_GPIO99__FUNC_SCL0 (MTK_PIN_NO(99) | 1)
+    #define PINMUX_GPIO100__FUNC_SDA0 (MTK_PIN_NO(100) | 1)
+
+    pio: pinctrl@10005000 {
+        compatible = "mediatek,mt6878-pinctrl";
+        reg = <0x10005000 0x1000>,
+              <0x11d10000 0x1000>,
+              <0x11d30000 0x1000>,
+              <0x11d40000 0x1000>,
+              <0x11d50000 0x1000>,
+              <0x11d60000 0x1000>,
+              <0x11e20000 0x1000>,
+              <0x11e30000 0x1000>,
+              <0x11eb0000 0x1000>,
+              <0x11ec0000 0x1000>,
+              <0x11ce0000 0x1000>,
+              <0x11de0000 0x1000>,
+              <0x11e60000 0x1000>,
+              <0x1c01e000 0x1000>;
+        reg-names = "base", "bl", "bm", "br", "bl1", "br1",
+                    "lm", "lt", "rm", "rt", "eint-e", "eint-s",
+                    "eint-w", "eint-c";
+        gpio-controller;
+        #gpio-cells = <2>;
+        gpio-ranges = <&pio 0 0 220>;
+        interrupt-controller;
+        interrupts = <GIC_SPI 239 IRQ_TYPE_LEVEL_HIGH 0>;
+        #interrupt-cells = <2>;
+
+        gpio-pins {
+            pins {
+                pinmux = <PINMUX_GPIO0__FUNC_GPIO0>;
+                bias-pull-up = <4000>;
+                drive-strength = <6>;
+            };
+        };
+
+        i2c0-pins {
+            pins-bus {
+                pinmux = <PINMUX_GPIO99__FUNC_SCL0>,
+                         <PINMUX_GPIO100__FUNC_SDA0>;
+                bias-pull-down = <75000>;
+                drive-strength-microamp = <1000>;
+            };
+        };
+    };