ASoC: littlemill: Use a widget to keep track of AIF2 clocking

Since we only need to clock AIF2 when it's actively in use start up the
FLL for it using a supply widget which supplies AIF2CLK. This both makes
the sequencing more robust and ensures we minimise power consumption.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/samsung/littlemill.c

@@ -67,28 +67,13 @@ static int littlemill_set_bias_level_post(struct snd_soc_card *card,
 					       enum snd_soc_bias_level level)
 {
 	struct snd_soc_dai *aif1_dai = card->rtd[0].codec_dai;
-	struct snd_soc_dai *aif2_dai = card->rtd[1].cpu_dai;
 	int ret;
 
 	if (dapm->dev != aif1_dai->dev)
 		return 0;
 
 	switch (level) {
 	case SND_SOC_BIAS_STANDBY:
-		ret = snd_soc_dai_set_sysclk(aif2_dai, WM8994_SYSCLK_MCLK2,
-					     32768, SND_SOC_CLOCK_IN);
-		if (ret < 0) {
-			pr_err("Failed to switch away from FLL2: %d\n", ret);
-			return ret;
-		}
-
-		ret = snd_soc_dai_set_pll(aif2_dai, WM8994_FLL2,
-					  0, 0, 0);
-		if (ret < 0) {
-			pr_err("Failed to stop FLL2: %d\n", ret);
-			return ret;
-		}
-
 		ret = snd_soc_dai_set_sysclk(aif1_dai, WM8994_SYSCLK_MCLK2,
 					     32768, SND_SOC_CLOCK_IN);
 		if (ret < 0) {
@@ -104,24 +89,6 @@ static int littlemill_set_bias_level_post(struct snd_soc_card *card,
 		}
 		break;
 
-	case SND_SOC_BIAS_PREPARE:
-		ret = snd_soc_dai_set_pll(aif2_dai, WM8994_FLL2,
-					  WM8994_FLL_SRC_BCLK, 64 * 8000,
-					  8000 * 256);
-		if (ret < 0) {
-			pr_err("Failed to start FLL: %d\n", ret);
-			return ret;
-		}
-
-		ret = snd_soc_dai_set_sysclk(aif2_dai, WM8994_SYSCLK_FLL2,
-					     8000 * 256,
-					     SND_SOC_CLOCK_IN);
-		if (ret < 0) {
-			pr_err("Failed to set SYSCLK: %d\n", ret);
-			return ret;
-		}
-		break;
-
 	default:
 		break;
 	}
@@ -197,11 +164,62 @@ static struct snd_soc_dai_link littlemill_dai[] = {
 	},
 };
 
+static int bbclk_ev(struct snd_soc_dapm_widget *w,
+		    struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_card *card = w->dapm->card;
+	struct snd_soc_dai *aif2_dai = card->rtd[1].cpu_dai;
+	int ret;
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		ret = snd_soc_dai_set_pll(aif2_dai, WM8994_FLL2,
+					  WM8994_FLL_SRC_BCLK, 64 * 8000,
+					  8000 * 256);
+		if (ret < 0) {
+			pr_err("Failed to start FLL: %d\n", ret);
+			return ret;
+		}
+
+		ret = snd_soc_dai_set_sysclk(aif2_dai, WM8994_SYSCLK_FLL2,
+					     8000 * 256,
+					     SND_SOC_CLOCK_IN);
+		if (ret < 0) {
+			pr_err("Failed to set SYSCLK: %d\n", ret);
+			return ret;
+		}
+		break;
+	case SND_SOC_DAPM_POST_PMD:
+		ret = snd_soc_dai_set_sysclk(aif2_dai, WM8994_SYSCLK_MCLK2,
+					     32768, SND_SOC_CLOCK_IN);
+		if (ret < 0) {
+			pr_err("Failed to switch away from FLL2: %d\n", ret);
+			return ret;
+		}
+
+		ret = snd_soc_dai_set_pll(aif2_dai, WM8994_FLL2,
+					  0, 0, 0);
+		if (ret < 0) {
+			pr_err("Failed to stop FLL2: %d\n", ret);
+			return ret;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static struct snd_soc_dapm_widget widgets[] = {
 	SND_SOC_DAPM_HP("Headphone", NULL),
 
 	SND_SOC_DAPM_MIC("AMIC", NULL),
 	SND_SOC_DAPM_MIC("DMIC", NULL),
+
+	SND_SOC_DAPM_SUPPLY_S("Baseband Clock", -1, SND_SOC_NOPM, 0, 0,
+			      bbclk_ev,
+			      SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMD),
 };
 
 static struct snd_soc_dapm_route audio_paths[] = {
@@ -214,6 +232,8 @@ static struct snd_soc_dapm_route audio_paths[] = {
 	{ "DMIC", NULL, "MICBIAS2" },   /* Default for DMICBIAS jumper */
 	{ "DMIC1DAT", NULL, "DMIC" },
 	{ "DMIC2DAT", NULL, "DMIC" },
+
+	{ "AIF2CLK", NULL, "Baseband Clock" },
 };
 
 static struct snd_soc_jack littlemill_headset;