ASoC: codecs: msm8916-wcd-analog: add MBHC support

MBHC (MultiButton Headset Control) support is available in pm8921 in two
blocks, one to detect mechanical headset insertion and removal and other
block to support headset type detection and 5 button detection and othe
features like impedance calculation.

This patch adds support to:
1> Support to NC and NO type of headset Jacks.
2> Mechanical insertion and detection of headset jack.
3> Detect a 3 pole Headphone and a 4 pole Headset.
4> Detect 5 buttons.

Tested it on DB410c with Audio Mezz board with 4 pole and 3 pole
headset/headphones.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/qcom,msm8916-wcd-analog.txt

@@ -31,9 +31,22 @@ Required properties
  - vdd-cdc-io-supply: phandle to VDD_CDC_IO regulator DT node.
  - vdd-cdc-tx-rx-cx-supply: phandle to VDD_CDC_TX/RX/CX regulator DT node.
  - vdd-micbias-supply: phandle of VDD_MICBIAS supply's regulator DT node.
-
 Optional Properties:
+ - qcom,mbhc-vthreshold-low: Array of 5 threshold voltages in mV for 5 buttons
+			     detection on headset when the mbhc is powered up
+			     by internal current source, this is a low power.
+ - qcom,mbhc-vthreshold-high: Array of 5 thresold voltages in mV for 5 buttons
+			      detection on headset when mbhc is powered up
+			       from micbias.
 - qcom,micbias-lvl:  Voltage (mV) for Mic Bias
+- qcom,hphl-jack-type-normally-open: boolean, present if hphl pin on jack is a
+				     NO (Normally Open). If not specified, then
+				     its assumed that hphl pin on jack is NC
+				     (Normally Closed).
+- qcom,gnd-jack-type-normally-open: boolean, present if gnd pin on jack is
+				    NO (Normally Open). If not specified, then
+				    its assumed that gnd pin on jack is NC
+				    (Normally Closed).
 - qcom,micbias1-ext-cap: boolean, present if micbias1 has external capacitor
 			 connected.
 - qcom,micbias2-ext-cap: boolean, present if micbias2 has external capacitor
@@ -49,6 +62,8 @@ spmi_bus {
 		reg-names = "pmic-codec-core";
 		clocks = <&gcc GCC_CODEC_DIGCODEC_CLK>;
 		clock-names = "mclk";
+		qcom,mbhc-vthreshold-low = <75 150 237 450 500>;
+		qcom,mbhc-vthreshold-high = <75 150 237 450 500>;
 		interrupt-parent = <&spmi_bus>;
 		interrupts = <0x1 0xf0 0x0 IRQ_TYPE_NONE>,
 			     <0x1 0xf0 0x1 IRQ_TYPE_NONE>,