ASoC: dt-bindings: wcd934x: add bindings for Headset Button detection

Add bindings required for Multi Button Headset detection.
WCD934x support Headsets with upto 8 buttons including, impedance measurement
on both L/R Headset speakers and cross connection detection.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210604115230.23259-2-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml

@@ -77,6 +77,31 @@ properties:
     minimum: 1800000
     maximum: 2850000
 
+  qcom,hphl-jack-type-normally-closed:
+    description: Indicates that HPHL jack switch type is normally closed
+    type: boolean
+
+  qcom,ground-jack-type-normally-closed:
+    description: Indicates that Headset Ground switch type is normally closed
+    type: boolean
+
+  qcom,mbhc-headset-vthreshold-microvolt:
+    description: Voltage threshold value for headset detection
+    minimum: 0
+    maximum: 2850000
+
+  qcom,mbhc-headphone-vthreshold-microvolt:
+    description: Voltage threshold value for headphone detection
+    minimum: 0
+    maximum: 2850000
+
+  qcom,mbhc-buttons-vthreshold-microvolt:
+    description:
+      Array of 8 Voltage threshold values corresponding to headset
+      button0 - button7
+    minItems: 8
+    maxItems: 8
+
   clock-output-names:
     const: mclk
 
@@ -159,6 +184,11 @@ examples:
         qcom,micbias2-microvolt = <1800000>;
         qcom,micbias3-microvolt = <1800000>;
         qcom,micbias4-microvolt = <1800000>;
+        qcom,hphl-jack-type-normally-closed;
+        qcom,ground-jack-type-normally-closed;
+        qcom,mbhc-buttons-vthreshold-microvolt = <75000 150000 237000 500000 500000 500000 500000 500000>;
+        qcom,mbhc-headset-vthreshold-microvolt = <1700000>;
+        qcom,mbhc-headphone-vthreshold-microvolt = <50000>;
         clock-names = "extclk";
         clocks = <&rpmhcc 2>;