ASoC: Implement WM8962 DMIC support

DMIC support is automatically disabled when none of the GPIOs are set up
to bring out the DMICCLK and DMICDAT pins at startup.

Note that there's no support for controlling DMIC routing except the power
control so the board DAPM configuration will need to manage DMIC enable and
disable if analogue mics (eg, a headset) also exist.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

sound/soc/codecs/wm8962.c

@@ -2468,6 +2468,7 @@ SND_SOC_DAPM_INPUT("IN3R"),
 SND_SOC_DAPM_INPUT("IN4L"),
 SND_SOC_DAPM_INPUT("IN4R"),
 SND_SOC_DAPM_INPUT("Beep"),
+SND_SOC_DAPM_INPUT("DMICDAT"),
 
 SND_SOC_DAPM_MICBIAS("MICBIAS", WM8962_PWR_MGMT_1, 1, 0),
 
@@ -2487,6 +2488,8 @@ SND_SOC_DAPM_MIXER("MIXINL", WM8962_PWR_MGMT_1, 5, 0,
 SND_SOC_DAPM_MIXER("MIXINR", WM8962_PWR_MGMT_1, 4, 0,
 		   mixinr, ARRAY_SIZE(mixinr)),
 
+SND_SOC_DAPM_AIF_IN("DMIC", NULL, 0, WM8962_PWR_MGMT_1, 10, 0),
+
 SND_SOC_DAPM_ADC("ADCL", "Capture", WM8962_PWR_MGMT_1, 3, 0),
 SND_SOC_DAPM_ADC("ADCR", "Capture", WM8962_PWR_MGMT_1, 2, 0),
 
@@ -2564,13 +2567,17 @@ static const struct snd_soc_dapm_route wm8962_intercon[] = {
 
 	{ "MICBIAS", NULL, "SYSCLK" },
 
+	{ "DMIC", NULL, "DMICDAT" },
+
 	{ "ADCL", NULL, "SYSCLK" },
 	{ "ADCL", NULL, "TOCLK" },
 	{ "ADCL", NULL, "MIXINL" },
+	{ "ADCL", NULL, "DMIC" },
 
 	{ "ADCR", NULL, "SYSCLK" },
 	{ "ADCR", NULL, "TOCLK" },
 	{ "ADCR", NULL, "MIXINR" },
+	{ "ADCR", NULL, "DMIC" },
 
 	{ "STL", "Left", "ADCL" },
 	{ "STL", "Right", "ADCR" },
@@ -3719,6 +3726,7 @@ static int wm8962_probe(struct snd_soc_codec *codec)
 					      dev);
 	u16 *reg_cache = codec->reg_cache;
 	int i, trigger, irq_pol;
+	bool dmicclk, dmicdat;
 
 	wm8962->codec = codec;
 	INIT_DELAYED_WORK(&wm8962->mic_work, wm8962_mic_work);
@@ -3856,6 +3864,29 @@ static int wm8962_probe(struct snd_soc_codec *codec)
 
 	wm8962_add_widgets(codec);
 
+	/* Save boards having to disable DMIC when not in use */
+	dmicclk = false;
+	dmicdat = false;
+	for (i = 0; i < WM8962_MAX_GPIO; i++) {
+		switch (snd_soc_read(codec, WM8962_GPIO_BASE + i)
+			& WM8962_GP2_FN_MASK) {
+		case WM8962_GPIO_FN_DMICCLK:
+			dmicclk = true;
+			break;
+		case WM8962_GPIO_FN_DMICDAT:
+			dmicdat = true;
+			break;
+		default:
+			break;
+		}
+	}
+	if (!dmicclk || !dmicdat) {
+		dev_dbg(codec->dev, "DMIC not in use, disabling\n");
+		snd_soc_dapm_nc_pin(&codec->dapm, "DMICDAT");
+	}
+	if (dmicclk != dmicdat)
+		dev_warn(codec->dev, "DMIC GPIOs partially configured\n");
+
 	wm8962_init_beep(codec);
 	wm8962_init_gpio(codec);