ASoC: wm8960: Let wm8960 codec driver manage its own MCLK

PATCH In review Zidan Wang 3 participants 7 messages Dec 9, 2014 – Dec 30, 2014

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Sound ASoC Wolfson microelectronics drivers

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Zidan Wang

author

2014-12-09 05:45 UTC #0 lore raw

PATCH v4 1/1 ASoC: wm8960: Let wm8960 codec driver manage its own MCLK

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 to save power.

Enable runtime power management, and auto enable/disable MCLK in pm_runtime resume and suspend. When wm8960 codec is being used, it will triger resume() to enable MCLK. When codec is not being used, it will triger suspend() to disable MCLK.

Signed-off-by Zidan Wang <[email protected]>

---
 sound/soc/codecs/wm8960.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

sound/soc/codecs/wm8960.c +46 -0

index 031a1ae..aff24a7 100644
@@ -15,6 +15,8 @@
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/pm.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
 #include <sound/core.h>

@@ -117,6 +119,7 @@ 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);

@@ -1002,6 +1005,13 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 	if (wm8960 == NULL)
 		return -ENOMEM;
 
+	wm8960->mclk = devm_clk_get(&i2c->dev, "codec_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);

@@ -1041,6 +1051,9 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 
 	i2c_set_clientdata(i2c, wm8960);
 
+	pm_runtime_enable(&i2c->dev);
+	pm_request_idle(&i2c->dev);
+
 	ret = snd_soc_register_codec(&i2c->dev,
 			&soc_codec_dev_wm8960, &wm8960_dai, 1);

@@ -1053,6 +1066,38 @@ static int wm8960_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef CONFIG_PM_RUNTIME
+static int wm8960_runtime_resume(struct device *dev)
+{
+	struct wm8960_priv *wm8960 = dev_get_drvdata(dev);
+	int ret;
+
+	if (!IS_ERR(wm8960->mclk)) {
+		ret = clk_prepare_enable(wm8960->mclk);
+		if (ret) {
+			dev_err(dev, "Failed to enable MCLK: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int wm8960_runtime_suspend(struct device *dev)
+{
+	struct wm8960_priv *wm8960 = dev_get_drvdata(dev);
+
+	if (!IS_ERR(wm8960->mclk))
+		clk_disable_unprepare(wm8960->mclk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops wm8960_pm = {
+	SET_RUNTIME_PM_OPS(wm8960_runtime_suspend, wm8960_runtime_resume, NULL)
+};
+
 static const struct i2c_device_id wm8960_i2c_id[] = {
 	{ "wm8960", 0 },
 	{ }

@@ -1070,6 +1115,7 @@ static struct i2c_driver wm8960_i2c_driver = {
 		.name = "wm8960",
 		.owner = THIS_MODULE,
 		.of_match_table = wm8960_of_match,
+		.pm = &wm8960_pm,
 	},
 	.probe =    wm8960_i2c_probe,
 	.remove =   wm8960_i2c_remove,

Signature · 1 line

1.9.1

Charles Keepax

Acked-by on v4 1/1

2014-12-11 09:15 UTC #1 lore raw

Quoted 11 lines · Zidan Wang

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 to save power.
Enable runtime power management, and auto enable/disable MCLK in pm_runtime resume and suspend. When wm8960 codec is being used, it will triger resume() to enable MCLK. When codec is not being used, it will triger suspend() to disable MCLK.
Signed-off-by Zidan Wang <[email protected]>
---

Acked-by Charles Keepax <[email protected]>

Thanks,
Charles

Mark Brown

maintainer

2014-12-22 18:10 UTC #2 lore raw

In reply to Zidan Wang

Quoted 15 lines · Zidan Wang

sound/soc/codecs/wm8960.c +7 -0

@@ -1002,6 +1005,13 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 	if (wm8960 == NULL)
 		return -ENOMEM;
 
+	wm8960->mclk = devm_clk_get(&i2c->dev, "codec_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);

sound/soc/codecs/wm8960.c static int wm8960_i2c_probe(struct i2c_client *i2c, · line 1059

Quoted 9 lines

sound/soc/codecs/wm8960.c +3 -0

@@ -1041,6 +1051,9 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 
 	i2c_set_clientdata(i2c, wm8960);
 
+	pm_runtime_enable(&i2c->dev);
+	pm_request_idle(&i2c->dev);
+
 	ret = snd_soc_register_codec(&i2c->dev,
 			&soc_codec_dev_wm8960, &wm8960_dai, 1);

This isn't going to work if PM is disabled (which is still a valid configuration). The general idiom for this is that the driver should start up with everything powered up then let runtime idle turn things off if they're not required. That way if runtime PM is disabled then the system will still work as everything will just stay powered on all the time.

Zidan Wang

author

2014-12-29 10:59 UTC #3 lore raw

Hi Mark,

I am so sorry for missing this letter.
You are right. When PM is disabled, the codec will not work. But there are also some codecs enable mclk in PM, such as wm8962, cs42xx8. And some codecs enable codec mclk in i2c probe(), startup() and set_bias_level(). It makes me confused.
Can you tell me what's the general idiom to enable mclk. Thanks.

Best Regards,
Zidan

-----Original Message-----
From: Mark Brown [mailto:[email protected]]
Sent: Tuesday, December 23, 2014 2:11 AM
To: Wang Zidan-B50113
Cc: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; Xiubo Li-B47053; [email protected]; [email protected]; [email protected]
Subject: Re: [alsa-devel][PATCH v4] ASoC: wm8960: Let wm8960 codec driver manage its own MCLK

Quoted 16 lines · Zidan Wang

sound/soc/codecs/wm8960.c +7 -0

@@ -1002,6 +1005,13 @@ static int wm8960_i2c_probe(struct i2c_client *i2c,
 	if (wm8960 == NULL)
 		return -ENOMEM;
 
+	wm8960->mclk = devm_clk_get(&i2c->dev, "codec_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);

sound/soc/codecs/wm8960.c static int wm8960_i2c_probe(struct i2c_client · line 1059

Quoted 9 lines

sound/soc/codecs/wm8960.c +3 -0

@@ -1041,6 +1051,9 @@ static int wm8960_i2c_probe(struct i2c_client 
 *i2c,
 
 	i2c_set_clientdata(i2c, wm8960);
 
+	pm_runtime_enable(&i2c->dev);
+	pm_request_idle(&i2c->dev);
+
 	ret = snd_soc_register_codec(&i2c->dev,
 			&soc_codec_dev_wm8960, &wm8960_dai, 1);

Mark Brown

maintainer

2014-12-29 16:05 UTC #4 lore raw

Quoted 1 line · Zidan Wang

Hi Mark,

Don't top post and please fix your mailer to word wrap within paragraphs and avoid corrupting the mail it's quoting.

Quoted 3 lines

You are right. When PM is disabled, the codec will not work. But there are also some codecs enable mclk in PM, such as wm8962, cs42xx8. And some codecs enable codec mclk in i2c probe(), startup() and set_bias_level(). It makes me confused.
Can you tell me what's the general idiom to enable mclk. Thanks.

Like I said in the mail to which you replied:

Quoted 1 line

Quoted 1 line
This isn't going to work if PM is disabled (which is still a valid configuration). The general idiom for this is that the driver should start up with everything powered up then let runtime idle turn things off if they're not required. That way if runtime PM is disabled then the system will still work as everything will just stay powered on all the time.

Zidan Wang

author

2014-12-30 02:28 UTC #5 lore raw

Quoted 13 lines · Mark Brown

Quoted 1 line · Zidan Wang
Hi Mark,
Don't top post and please fix your mailer to word wrap within paragraphs and avoid corrupting the mail it's quoting.
Quoted 3 lines
You are right. When PM is disabled, the codec will not work. But there are also some codecs enable mclk in PM, such as wm8962, cs42xx8. And some codecs enable codec mclk in i2c probe(), startup() and set_bias_level(). It makes me confused.
Can you tell me what's the general idiom to enable mclk. Thanks.
Like I said in the mail to which you replied:
Quoted 1 line
Quoted 1 line
This isn't going to work if PM is disabled (which is still a valid configuration). The general idiom for this is that the driver should start up with everything powered up then let runtime idle turn things off if they're not required. That way if runtime PM is disabled then the system will still work as everything will just stay powered on all the time.

I want put mclk enable to set_bias_level. Do you thinks it make sense?

Mark Brown

maintainer

2014-12-30 16:53 UTC #6 lore raw

Quoted 1 line · Zidan Wang

I want put mclk enable to set_bias_level. Do you thinks it make sense?

That should work as well, yes.