[alsa-devel][PATCH v2 1/2] ASoC: wm8960: Let wm8960 codec driver manage its own MCLK

[Zidan Wang]

From: Zidan Wang <b50113@xxxxxxxxxxxxx>

When we want to use wm8960 codec, we should enable its MCLK in machine driver.
It's reasonable for wm8960 codec driver to manage its own MCLK.

When current bias_level is SND_SOC_BIAS_ON, it is preparing for a transition
away from ON. In this case, disable the codec mclk. When current bias_level
is not SND_SOC_BIAS_ON, it preparing for a transition to ON. In this case,
enable the codec mclk.

Signed-off-by: Zidan Wang <b50113@xxxxxxxxxxxxx>
---
 sound/soc/codecs/wm8960.c | 51 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 48 insertions(+), 3 deletions(-)

diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
index 75cd7de..fd25973 100644
--- a/sound/soc/codecs/wm8960.c
+++ b/sound/soc/codecs/wm8960.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/pm.h>
+#include <linux/clk.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <sound/core.h>
@@ -117,6 +118,7 @@ static bool wm8960_volatile(struct device *dev, unsigned int reg)
 }
 
 struct wm8960_priv {
+	struct clk *mclk;
 	struct regmap *regmap;
 	int (*set_bias_level)(struct snd_soc_codec *,
 			      enum snd_soc_bias_level level);
@@ -618,14 +620,38 @@ static int wm8960_set_bias_level_out3(struct snd_soc_codec *codec,
 				      enum snd_soc_bias_level level)
 {
 	struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
+	int ret;
 
 	switch (level) {
 	case SND_SOC_BIAS_ON:
 		break;
 
 	case SND_SOC_BIAS_PREPARE:
-		/* Set VMID to 2x50k */
-		snd_soc_update_bits(codec, WM8960_POWER1, 0x180, 0x80);
+		switch (codec->dapm.bias_level) {
+		case SND_SOC_BIAS_STANDBY:
+			if (!IS_ERR(wm8960->mclk)) {
+				ret = clk_prepare_enable(wm8960->mclk);
+				if (ret) {
+					dev_err(codec->dev,
+						"Failed to enable MCLK: %d\n",
+						ret);
+					return ret;
+				}
+			}
+
+			/* Set VMID to 2x50k */
+			snd_soc_update_bits(codec, WM8960_POWER1, 0x180, 0x80);
+			break;
+
+		case SND_SOC_BIAS_ON:
+			if (!IS_ERR(wm8960->mclk))
+				clk_disable_unprepare(wm8960->mclk);
+			break;
+
+		default:
+			break;
+		}
+
 		break;
 
 	case SND_SOC_BIAS_STANDBY:
@@ -674,7 +700,7 @@ static int wm8960_set_bias_level_capless(struct snd_soc_codec *codec,
 					 enum snd_soc_bias_level level)
 {
 	struct wm8960_priv *wm8960 = snd_soc_codec_get_drvdata(codec);
-	int reg;
+	int reg, ret;
 
 	switch (level) {
 	case SND_SOC_BIAS_ON:
@@ -715,9 +741,22 @@ static int wm8960_set_bias_level_capless(struct snd_soc_codec *codec,
 					    WM8960_VREF, WM8960_VREF);
 
 			msleep(100);
+
+			if (!IS_ERR(wm8960->mclk)) {
+				ret = clk_prepare_enable(wm8960->mclk);
+				if (ret) {
+					dev_err(codec->dev,
+						"Failed to enable MCLK: %d\n",
+						ret);
+					return ret;
+				}
+			}
 			break;
 
 		case SND_SOC_BIAS_ON:
+			if (!IS_ERR(wm8960->mclk))
+				clk_disable_unprepare(wm8960->mclk);
+
 			/* Enable anti-pop mode */
 			snd_soc_update_bits(codec, WM8960_APOP1,
 					    WM8960_POBCTRL | WM8960_SOFT_ST |
@@ -1002,6 +1041,12 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 	if (wm8960 == NULL)
 		return -ENOMEM;
 
+	wm8960->mclk = devm_clk_get(&i2c->dev, "mclk");
+	if (IS_ERR(wm8960->mclk)) {
+		if (PTR_ERR(wm8960->mclk) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+	}
+
 	wm8960->regmap = devm_regmap_init_i2c(i2c, &wm8960_regmap);
 	if (IS_ERR(wm8960->regmap))
 		return PTR_ERR(wm8960->regmap);
-- 
1.9.1

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