[PATCH v1 2/2] ASoC: dmic: Add optional dmic selection

[Ajye Huang]

Having two DMICs, a front DMIC and a rear DMIC,
but only host audio input AUX port0 is used for these two Dmics.
A "dmic_sel-gpios" property is used for a mixer control to switch
the dmic signal source between the Front and Rear Dmic.

usage: amixer -c0 cset name='Dmic Mux' 'FrontMic'
usage: amixer -c0 cset name='Dmic Mux' 'RearMic'

Refer to this one as an example,
commit 3cfbf07c6d27
("ASoC: qcom: sc7180: Modify machine driver for 2mic")

Signed-off-by: Ajye Huang <ajye_huang at compal.corp-partner.google.com>
---
 sound/soc/codecs/dmic.c | 52 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c
index 4fd6f97e5a49..5c56fbcdb3e6 100644
--- a/sound/soc/codecs/dmic.c
+++ b/sound/soc/codecs/dmic.c
@@ -28,8 +28,50 @@ struct dmic {
 	int wakeup_delay;
 	/* Delay after DMIC mode switch */
 	int modeswitch_delay;
+	struct gpio_desc *dmic_sel;
+	int dmic_switch;
 };
 
+static int dmic_sel_get(struct snd_kcontrol *kcontrol,
+		    struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_dapm(kcontrol);
+	struct snd_soc_component *component = snd_soc_dapm_to_component(dapm);
+	struct dmic *dmic = snd_soc_component_get_drvdata(component);
+
+	ucontrol->value.integer.value[0] = dmic->dmic_switch;
+	return 0;
+}
+
+static int dmic_sel_set(struct snd_kcontrol *kcontrol,
+		    struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_dapm_context *dapm = snd_soc_dapm_kcontrol_dapm(kcontrol);
+	struct snd_soc_component *component = snd_soc_dapm_to_component(dapm);
+	struct dmic *dmic = snd_soc_component_get_drvdata(component);
+
+	dmic->dmic_switch = ucontrol->value.integer.value[0];
+	if (dmic->dmic_sel) {
+		gpiod_set_value(dmic->dmic_sel, dmic->dmic_switch);
+		dev_info(dapm->dev, "%s value %d\n", __func__, dmic->dmic_switch);
+	} else
+		dev_info(dapm->dev, "%s without dmic_sel-gpios\n", __func__);
+
+	return 0;
+}
+
+static const char * const dmic_mux_text[] = {
+	"FrontMic",
+	"RearMic",
+};
+
+static SOC_ENUM_SINGLE_DECL(dmic_enum,
+			    SND_SOC_NOPM, 0, dmic_mux_text);
+
+static const struct snd_kcontrol_new dmic_mux_control =
+	SOC_DAPM_ENUM_EXT("DMIC Select Mux", dmic_enum,
+			  dmic_sel_get, dmic_sel_set);
+
 static int dmic_daiops_trigger(struct snd_pcm_substream *substream,
 			       int cmd, struct snd_soc_dai *dai)
 {
@@ -115,6 +157,11 @@ static int dmic_component_probe(struct snd_soc_component *component)
 	if (dmic->modeswitch_delay > MAX_MODESWITCH_DELAY)
 		dmic->modeswitch_delay = MAX_MODESWITCH_DELAY;
 
+	dmic->dmic_sel = devm_gpiod_get_optional(component->dev,
+						"dmic_sel", GPIOD_OUT_LOW);
+	if (IS_ERR(dmic->dmic_sel))
+		return PTR_ERR(dmic->dmic_sel);
+
 	snd_soc_component_set_drvdata(component, dmic);
 
 	return 0;
@@ -125,10 +172,15 @@ static const struct snd_soc_dapm_widget dmic_dapm_widgets[] = {
 			       SND_SOC_NOPM, 0, 0, dmic_aif_event,
 			       SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
 	SND_SOC_DAPM_INPUT("DMic"),
+	SND_SOC_DAPM_MIC("DMIC", NULL),
+	SND_SOC_DAPM_MUX("Dmic Mux", SND_SOC_NOPM, 0, 0, &dmic_mux_control),
 };
 
 static const struct snd_soc_dapm_route intercon[] = {
 	{"DMIC AIF", NULL, "DMic"},
+	/* digital mics */
+	{"Dmic Mux", "FrontMic", "DMIC"},
+	{"Dmic Mux", "RearMic", "DMIC"},
 };
 
 static const struct snd_soc_component_driver soc_dmic = {
-- 
2.25.1