[alsa-devel] [PATCH] ASoC: nau8825: reduce stanby power consumption

[John Hsu]

Fix unnecessary widget power up when standby;
And decrease internal clock frequency to save power.

Signed-off-by: John Hsu <KCHSU0 at nuvoton.com>
---
 sound/soc/codecs/nau8825.c | 49 +++++++++++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c
index 52882e4..f9752cc 100644
--- a/sound/soc/codecs/nau8825.c
+++ b/sound/soc/codecs/nau8825.c
@@ -262,6 +262,29 @@ static int nau8825_playback_event(struct snd_soc_dapm_widget *w,
 	return 0;
 }
 
+static int nau8825_dacr_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);
+	struct nau8825 *nau8825 = snd_soc_codec_get_drvdata(codec);
+
+	switch (event) {
+	case SND_SOC_DAPM_POST_PMU:
+		regmap_update_bits(nau8825->regmap, NAU8825_REG_ENA_CTRL,
+			NAU8825_ENABLE_DACR, NAU8825_ENABLE_DACR);
+		break;
+	case SND_SOC_DAPM_POST_PMD:
+		if (!nau8825->irq)
+			regmap_update_bits(nau8825->regmap,
+			NAU8825_REG_ENA_CTRL, NAU8825_ENABLE_DACR, 0);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 
 static const char * const nau8825_adc_decimation[] = {
 	"32", "64", "128", "256"
@@ -337,16 +360,17 @@ static const struct snd_soc_dapm_widget nau8825_dapm_widgets[] = {
 		0),
 
 	/* ADC for button press detection */
-	SND_SOC_DAPM_ADC("SAR", NULL, NAU8825_REG_SAR_CTRL,
-		NAU8825_SAR_ADC_EN_SFT, 0),
+	SND_SOC_DAPM_SUPPLY("SAR", NAU8825_REG_SAR_CTRL,
+		NAU8825_SAR_ADC_EN_SFT, 0, NULL, 0),
 
 	SND_SOC_DAPM_DAC("ADACL", NULL, NAU8825_REG_RDAC, 12, 0),
 	SND_SOC_DAPM_DAC("ADACR", NULL, NAU8825_REG_RDAC, 13, 0),
 	SND_SOC_DAPM_SUPPLY("ADACL Clock", NAU8825_REG_RDAC, 8, 0, NULL, 0),
 	SND_SOC_DAPM_SUPPLY("ADACR Clock", NAU8825_REG_RDAC, 9, 0, NULL, 0),
 
-	SND_SOC_DAPM_DAC("DDACR", NULL, NAU8825_REG_ENA_CTRL,
-		NAU8825_ENABLE_DACR_SFT, 0),
+	SND_SOC_DAPM_DAC_E("DDACR", NULL, SND_SOC_NOPM, 0, 0,
+		nau8825_dacr_event, SND_SOC_DAPM_POST_PMU |
+		SND_SOC_DAPM_POST_PMD),
 	SND_SOC_DAPM_DAC("DDACL", NULL, NAU8825_REG_ENA_CTRL,
 		NAU8825_ENABLE_DACL_SFT, 0),
 	SND_SOC_DAPM_SUPPLY("DDAC Clock", NAU8825_REG_ENA_CTRL, 6, 0, NULL, 0),
@@ -878,13 +902,6 @@ static int nau8825_codec_probe(struct snd_soc_codec *codec)
 
 	nau8825->dapm = dapm;
 
-	/* The interrupt clock is gated by x1[10:8],
-	 * one of them needs to be enabled all the time for
-	 * interrupts to happen.
-	 */
-	snd_soc_dapm_force_enable_pin(dapm, "DDACR");
-	snd_soc_dapm_sync(dapm);
-
 	/* Unmask interruptions. Handler uses dapm object so we can enable
 	 * interruptions only after dapm is fully initialized.
 	 */
@@ -1075,6 +1092,12 @@ static int nau8825_configure_sysclk(struct nau8825 *nau8825, int clk_id,
 			NAU8825_DCO_EN);
 		regmap_update_bits(regmap, NAU8825_REG_CLK_DIVIDER,
 			NAU8825_CLK_SRC_MASK, NAU8825_CLK_SRC_VCO);
+		regmap_update_bits(regmap, NAU8825_REG_CLK_DIVIDER,
+			NAU8825_CLK_MCLK_SRC_MASK, 0xf);
+		regmap_update_bits(regmap, NAU8825_REG_FLL1,
+			NAU8825_FLL_RATIO_MASK, 0x10);
+		regmap_update_bits(regmap, NAU8825_REG_FLL6,
+			NAU8825_SDM_EN, NAU8825_SDM_EN);
 		if (nau8825->mclk_freq) {
 			clk_disable_unprepare(nau8825->mclk);
 			nau8825->mclk_freq = 0;
@@ -1309,9 +1332,7 @@ static int nau8825_setup_irq(struct nau8825 *nau8825)
 	/* Enable internal VCO needed for interruptions */
 	nau8825_configure_sysclk(nau8825, NAU8825_CLK_INTERNAL, 0);
 
-	/* Enable DDACR needed for interrupts
-	 * It is the same as force_enable_pin("DDACR") we do later
-	 */
+	/* Enable DDACR needed for interrupts */
 	regmap_update_bits(regmap, NAU8825_REG_ENA_CTRL,
 		NAU8825_ENABLE_DACR, NAU8825_ENABLE_DACR);
 
-- 
2.6.4