ASoC: Documentation: Add google, cros-ec-codec

Add documentation for Chrome EC codec driver.

Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt b/Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt
new file mode 100644
index 000000000000..1084f7f22eea
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+++ b/Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt
@@ -0,0 +1,26 @@
+* Audio codec controlled by ChromeOS EC
+
+Google's ChromeOS EC codec is a digital mic codec provided by the
+Embedded Controller (EC) and is controlled via a host-command interface.
+
+An EC codec node should only be found as a sub-node of the EC node (see
+Documentation/devicetree/bindings/mfd/cros-ec.txt).
+
+Required properties:
+- compatible: Must contain "google,cros-ec-codec"
+- #sound-dai-cells: Should be 1. The cell specifies number of DAIs.
+- max-dmic-gain: A number for maximum gain in dB on digital microphone.
+
+Example:
+
+cros-ec@0 {
+	compatible = "google,cros-ec-spi";
+
+	...
+
+	cros_ec_codec: ec-codec {
+		compatible = "google,cros-ec-codec";
+		#sound-dai-cells = <1>;
+		max-dmic-gain = <43>;
+	};
+};