ASoC: dt-bindings: Convert Simple Amplifier binding to a schema

Simple audio amplifiers are supported by Linux with a matching device
tree binding.

Now that we have the DT validation in place, let's convert the device
tree bindings for that driver over to a YAML schema.

Cc: alsa-devel@alsa-project.org
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901091852.479202-5-maxime@cerno.techSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/simple-amplifier.txt

-Simple Amplifier Audio Driver
-
-Required properties:
-- compatible : "dioo,dio2125" or "simple-audio-amplifier"
-
-Optional properties:
-- enable-gpios : the gpio connected to the enable pin of the simple amplifier
-- VCC-supply   : power supply for the device, as covered
-                 in Documentation/devicetree/bindings/regulator/regulator.txt
-
-Example:
-
-amp: analog-amplifier {
-	compatible = "simple-audio-amplifier";
-	VCC-supply = <&regulator>;
-	enable-gpios = <&gpio GPIOH_3 0>;
-};

Documentation/devicetree/bindings/sound/simple-audio-amplifier.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/simple-audio-amplifier.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Simple Audio Amplifier Device Tree Bindings
+
+maintainers:
+  - Jerome Brunet <jbrunet@baylibre.com>
+
+properties:
+  compatible:
+    enum:
+      - dioo,dio2125
+      - simple-audio-amplifier
+
+  enable-gpios:
+    maxItems: 1
+
+  VCC-supply:
+    description: >
+      power supply for the device
+
+  sound-name-prefix:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: >
+      See ./name-prefix.txt
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/meson8-gpio.h>
+
+    analog-amplifier {
+        compatible = "simple-audio-amplifier";
+        VCC-supply = <&regulator>;
+        enable-gpios = <&gpio GPIOH_3 0>;
+    };
+
+...