dt-bindings: ASoC: Add WSA881x bindings

This patch adds bindings for WSA8810/WSA8815 Class-D Smart Speaker
Amplifier. This Amplifier also has a simple thermal sensor for
over temperature and speaker protection.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200107135929.3267-2-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/qcom,wsa881x.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/qcom,wsa881x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bindings for Qualcomm WSA8810/WSA8815 Class-D Smart Speaker Amplifier
+
+maintainers:
+  - Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+
+description: |
+  WSA8810 is a class-D smart speaker amplifier and WSA8815
+  is a high-output power class-D smart speaker amplifier.
+  Their primary operating mode uses a SoundWire digital audio
+  interface. This binding is for SoundWire interface.
+
+properties:
+  compatible:
+    const: sdw10217201000
+
+  reg:
+    maxItems: 1
+
+  powerdown-gpios:
+    description: GPIO spec for Powerdown/Shutdown line to use
+    maxItems: 1
+
+  '#thermal-sensor-cells':
+    const: 0
+
+  '#sound-dai-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - powerdown-gpios
+  - "#thermal-sensor-cells"
+  - "#sound-dai-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    soundwire@c2d0000 {
+        #address-cells = <2>;
+        #size-cells = <0>;
+        reg = <0x0c2d0000 0x2000>;
+
+        speaker@0,1 {
+            compatible = "sdw10217201000";
+            reg = <0 1>;
+            powerdown-gpios = <&wcdpinctrl 2 0>;
+            #thermal-sensor-cells = <0>;
+            #sound-dai-cells = <0>;
+        };
+
+        speaker@0,2 {
+            compatible = "sdw10217201000";
+            reg = <0 2>;
+            powerdown-gpios = <&wcdpinctrl 2 0>;
+            #thermal-sensor-cells = <0>;
+            #sound-dai-cells = <0>;
+        };
+    };
+
+...