ASoC: dt-bindings: mediatek,mt8188-mt6359: add mt8188-mt6359 document

Add document for mt8188 board with mt6359.
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230116034131.23943-14-trevor.wu@mediatek.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/mediatek,mt8188-mt6359.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/mediatek,mt8188-mt6359.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek MT8188 ASoC sound card
+
+maintainers:
+  - Trevor Wu <trevor.wu@mediatek.com>
+
+properties:
+  compatible:
+    const: mediatek,mt8188-mt6359-evb
+
+  model:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: User specified audio sound card name
+
+  audio-routing:
+    $ref: /schemas/types.yaml#/definitions/non-unique-string-array
+    description:
+      A list of the connections between audio components. Each entry is a
+      sink/source pair of strings. Valid names could be the input or output
+      widgets of audio components, power supplies, MicBias of codec and the
+      software switch.
+
+  mediatek,platform:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: The phandle of MT8188 ASoC platform.
+
+patternProperties:
+  "^dai-link-[0-9]+$":
+    type: object
+    description:
+      Container for dai-link level properties and CODEC sub-nodes.
+
+    properties:
+      link-name:
+        description:
+          This property corresponds to the name of the BE dai-link to which
+          we are going to update parameters in this node.
+        items:
+          enum:
+            - ADDA_BE
+            - DPTX_BE
+            - ETDM1_IN_BE
+            - ETDM2_IN_BE
+            - ETDM1_OUT_BE
+            - ETDM2_OUT_BE
+            - ETDM3_OUT_BE
+            - PCM1_BE
+
+      codec:
+        description: Holds subnode which indicates codec dai.
+        type: object
+        additionalProperties: false
+        properties:
+          sound-dai:
+            minItems: 1
+            maxItems: 2
+        required:
+          - sound-dai
+
+    additionalProperties: false
+
+    required:
+      - link-name
+      - codec
+
+additionalProperties: false
+
+required:
+  - compatible
+  - mediatek,platform
+
+examples:
+  - |
+    sound {
+        compatible = "mediatek,mt8188-mt6359-evb";
+        mediatek,platform = <&afe>;
+        pinctrl-names = "default";
+        pinctrl-0 = <&aud_pins_default>;
+        audio-routing =
+            "Headphone", "Headphone L",
+            "Headphone", "Headphone R",
+            "AIN1", "Headset Mic";
+        dai-link-0 {
+            link-name = "ETDM3_OUT_BE";
+
+            codec {
+                sound-dai = <&hdmi0>;
+            };
+        };
+    };
+
+...