ASoC: ak4642: enable stereo line output power-save mode

ak4642 has power-save mode for stereo line to reduce pop noise.
This patch enables it.
Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/ak4642.c

@@ -97,6 +97,9 @@
 #define PMMP		(1 << 2) /* MPWR pin Power Management */
 #define MGAIN0		(1 << 0) /* MIC amp gain*/
 
+/* SG_SL2 */
+#define LOPS		(1 << 6) /* Stero Line-out Power Save Mode */
+
 /* TIMER */
 #define ZTM(param)	((param & 0x3) << 4) /* ALC Zero Crossing TimeOut */
 #define WTM(param)	(((param & 0x4) << 4) | ((param & 0x3) << 2))
@@ -168,6 +171,29 @@ static const struct snd_kcontrol_new ak4642_lout_mixer_controls[] = {
 	SOC_DAPM_SINGLE("DACL", SG_SL1, 4, 1, 0),
 };
 
+/* event handlers */
+static int ak4642_lout_event(struct snd_soc_dapm_widget *w,
+			     struct snd_kcontrol *kcontrol, int event)
+{
+	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMD:
+	case SND_SOC_DAPM_PRE_PMU:
+		/* Power save mode ON */
+		snd_soc_update_bits(codec, SG_SL2, LOPS, LOPS);
+		break;
+	case SND_SOC_DAPM_POST_PMU:
+	case SND_SOC_DAPM_POST_PMD:
+		/* Power save mode OFF */
+		mdelay(300);
+		snd_soc_update_bits(codec, SG_SL2, LOPS, 0);
+		break;
+	}
+
+	return 0;
+}
+
 static const struct snd_soc_dapm_widget ak4642_dapm_widgets[] = {
 
 	/* Outputs */
@@ -182,9 +208,12 @@ static const struct snd_soc_dapm_widget ak4642_dapm_widgets[] = {
 
 	SND_SOC_DAPM_PGA("DACH", MD_CTL4, 0, 0, NULL, 0),
 
-	SND_SOC_DAPM_MIXER("LINEOUT Mixer", PW_MGMT1, 3, 0,
+	SND_SOC_DAPM_MIXER_E("LINEOUT Mixer", PW_MGMT1, 3, 0,
 			   &ak4642_lout_mixer_controls[0],
-			   ARRAY_SIZE(ak4642_lout_mixer_controls)),
+			   ARRAY_SIZE(ak4642_lout_mixer_controls),
+			   ak4642_lout_event,
+			   SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_POST_PMU |
+			   SND_SOC_DAPM_PRE_PMD | SND_SOC_DAPM_POST_PMD),
 
 	/* DAC */
 	SND_SOC_DAPM_DAC("DAC", NULL, PW_MGMT1, 2, 0),