ASoC: tegra: Add sink for the internal mic to tegra_max98090

Also adds a control for the pin of the internal mic, so userspace can
apply policy when the state of the external mic jack changes.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/nvidia,tegra-audio-max98090.txt

@@ -18,6 +18,7 @@ Required properties:
   * Headphones
   * Speakers
   * Mic Jack
+  * Int Mic
 
 - nvidia,i2s-controller : The phandle of the Tegra I2S controller that's
   connected to the CODEC.

sound/soc/tegra/tegra_max98090.c

@@ -133,11 +133,13 @@ static const struct snd_soc_dapm_widget tegra_max98090_dapm_widgets[] = {
 	SND_SOC_DAPM_HP("Headphones", NULL),
 	SND_SOC_DAPM_SPK("Speakers", NULL),
 	SND_SOC_DAPM_MIC("Mic Jack", NULL),
+	SND_SOC_DAPM_MIC("Int Mic", NULL),
 };
 
 static const struct snd_kcontrol_new tegra_max98090_controls[] = {
 	SOC_DAPM_PIN_SWITCH("Headphones"),
 	SOC_DAPM_PIN_SWITCH("Speakers"),
+	SOC_DAPM_PIN_SWITCH("Int Mic"),
 };
 
 static int tegra_max98090_asoc_init(struct snd_soc_pcm_runtime *rtd)