dt-bindings: sound: Convert Allwinner SPDIF binding to YAML

The Allwinner SoCs feature an SPDIF controller across multiple SoC
generations.

However, earlier generations were a bit simpler than the subsequent ones,
and for example would always have RX and TX capabilities, and no reset
lines.

In order to express this, let's create two YAML schemas instead of the free
form text we had before.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/allwinner,sun4i-a10-spdif.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/allwinner,sun4i-a10-spdif.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A10 S/PDIF Controller Device Tree Bindings
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Liam Girdwood <lgirdwood@gmail.com>
+  - Mark Brown <broonie@kernel.org>
+  - Maxime Ripard <maxime.ripard@bootlin.com>
+
+properties:
+  "#sound-dai-cells":
+    const: 0
+
+  compatible:
+    oneOf:
+      - const: allwinner,sun4i-a10-spdif
+      - const: allwinner,sun6i-a31-spdif
+      - const: allwinner,sun8i-h3-spdif
+      - items:
+          - const: allwinner,sun8i-a83t-spdif
+          - const: allwinner,sun8i-h3-spdif
+      - items:
+          - const: allwinner,sun50i-a64-spdif
+          - const: allwinner,sun8i-h3-spdif
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Bus Clock
+      - description: Module Clock
+
+  clock-names:
+    items:
+      - const: apb
+      - const: spdif
+
+  dmas:
+    items:
+      - description: RX DMA Channel
+      - description: TX DMA Channel
+
+  dma-names:
+    items:
+      - const: rx
+      - const: tx
+
+  # Even though it only applies to subschemas under the conditionals,
+  # not listing them here will trigger a warning because of the
+  # additionalsProperties set to false.
+  resets:
+    maxItems: 1
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - allwinner,sun6i-a31-spdif
+              - allwinner,sun8i-h3-spdif
+
+    then:
+      required:
+        - resets
+
+required:
+  - "#sound-dai-cells"
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - dmas
+  - dma-names
+
+additionalProperties: false
+
+examples:
+  - |
+    spdif: spdif@1c21000 {
+        #sound-dai-cells = <0>;
+        compatible = "allwinner,sun4i-a10-spdif";
+        reg = <0x01c21000 0x40>;
+        interrupts = <13>;
+        clocks = <&apb0_gates 1>, <&spdif_clk>;
+        clock-names = "apb", "spdif";
+        dmas = <&dma 0 2>, <&dma 0 2>;
+        dma-names = "rx", "tx";
+    };
+
+...

Documentation/devicetree/bindings/sound/sunxi,sun4i-spdif.txt

-Allwinner Sony/Philips Digital Interface Format (S/PDIF) Controller
-
-The Allwinner S/PDIF audio block is a transceiver that allows the
-processor to receive and transmit digital audio via an coaxial cable or
-a fibre cable.
-For now only playback is supported.
-
-Required properties:
-
-  - compatible		: should be one of the following:
-    - "allwinner,sun4i-a10-spdif": for the Allwinner A10 SoC
-    - "allwinner,sun6i-a31-spdif": for the Allwinner A31 SoC
-    - "allwinner,sun8i-h3-spdif": for the Allwinner H3 SoC
-
-  - reg			: Offset and length of the register set for the device.
-
-  - interrupts		: Contains the spdif interrupt.
-
-  - dmas		: Generic dma devicetree binding as described in
-			  Documentation/devicetree/bindings/dma/dma.txt.
-
-  - dma-names		: Two dmas have to be defined, "tx" and "rx".
-
-  - clocks		: Contains an entry for each entry in clock-names.
-
-  - clock-names		: Includes the following entries:
-	"apb"		  clock for the spdif bus.
-	"spdif"		  clock for spdif controller.
-
-  - resets		: reset specifier for the ahb reset (A31 and newer only)
-
-Example:
-
-spdif: spdif@1c21000 {
-	compatible = "allwinner,sun4i-a10-spdif";
-	reg = <0x01c21000 0x40>;
-	interrupts = <13>;
-	clocks = <&apb0_gates 1>, <&spdif_clk>;
-	clock-names = "apb", "spdif";
-	dmas = <&dma 0 2>, <&dma 0 2>;
-	dma-names = "rx", "tx";
-};