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Commit 5de7f9b2 authored by Mark Brown's avatar Mark Brown
Browse files

ASoC: Actively manage MCLK for AT91SAM9G20-EK 



We have software control of the MCLK for the WM8731 so save a bit of
power by actively managing it within the machine driver, enabling it
only while the codec is active.

Once ASoC supports multiple boards and doesn't require the soc-audio
device the initial clock setup should be pushed down into the arch/arm
code but for now this reduces merge issues.

Tested-by: default avatarSedji Gaouaou <sedji.gaouaou@atmel.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 40135ea0

sound/soc/atmel/sam9g20_wm8731.c

+65 −3
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ 
#include "atmel-pcm.h"

#include "atmel_ssc_dai.h"



#define MCLK_RATE 12000000



static struct clk *mclk;



static int at91sam9g20ek_startup(struct snd_pcm_substream *substream)

{
@@ -60,11 +63,12 @@ static int at91sam9g20ek_startup(struct snd_pcm_substream *substream) 
	struct snd_soc_dai *codec_dai = rtd->dai->codec_dai;

	int ret;



	/* codec system clock is supplied by PCK0, set to 12MHz */

	ret = snd_soc_dai_set_sysclk(codec_dai, WM8731_SYSCLK,

		12000000, SND_SOC_CLOCK_IN);

	if (ret < 0)

		MCLK_RATE, SND_SOC_CLOCK_IN);

	if (ret < 0) {

		clk_disable(mclk);

		return ret;

	}



	return 0;

}
@@ -190,6 +194,31 @@ static struct snd_soc_ops at91sam9g20ek_ops = { 
	.shutdown = at91sam9g20ek_shutdown,

};



static int at91sam9g20ek_set_bias_level(struct snd_soc_card *card,

					enum snd_soc_bias_level level)

{

	static int mclk_on;

	int ret = 0;



	switch (level) {

	case SND_SOC_BIAS_ON:

	case SND_SOC_BIAS_PREPARE:

		if (!mclk_on)

			ret = clk_enable(mclk);

		if (ret == 0)

			mclk_on = 1;

		break;



	case SND_SOC_BIAS_OFF:

	case SND_SOC_BIAS_STANDBY:

		if (mclk_on)

			clk_disable(mclk);

		mclk_on = 0;

		break;

	}



	return ret;

}



static const struct snd_soc_dapm_widget at91sam9g20ek_dapm_widgets[] = {

	SND_SOC_DAPM_MIC("Int Mic", NULL),
@@ -248,6 +277,7 @@ static struct snd_soc_card snd_soc_at91sam9g20ek = { 
	.platform = &atmel_soc_platform,

	.dai_link = &at91sam9g20ek_dai,

	.num_links = 1,

	.set_bias_level = at91sam9g20ek_set_bias_level,

};



static struct wm8731_setup_data at91sam9g20ek_wm8731_setup = {
@@ -267,11 +297,37 @@ static int __init at91sam9g20ek_init(void) 
{

	struct atmel_ssc_info *ssc_p = at91sam9g20ek_dai.cpu_dai->private_data;

	struct ssc_device *ssc = NULL;

	struct clk *pllb;

	int ret;



	if (!machine_is_at91sam9g20ek())

		return -ENODEV;



	/*

	 * Codec MCLK is supplied by PCK0 - set it up.

	 */

	mclk = clk_get(NULL, "pck0");

	if (IS_ERR(mclk)) {

		printk(KERN_ERR "ASoC: Failed to get MCLK\n");

		ret = PTR_ERR(mclk);

		goto err;

	}



	pllb = clk_get(NULL, "pllb");

	if (IS_ERR(mclk)) {

		printk(KERN_ERR "ASoC: Failed to get PLLB\n");

		ret = PTR_ERR(mclk);

		goto err_mclk;

	}

	ret = clk_set_parent(mclk, pllb);

	clk_put(pllb);

	if (ret != 0) {

		printk(KERN_ERR "ASoC: Failed to set MCLK parent\n");

		goto err_mclk;

	}



	clk_set_rate(mclk, MCLK_RATE);



	/*

	 * Request SSC device

	 */
@@ -303,6 +359,10 @@ static int __init at91sam9g20ek_init(void) 
	return ret;



err_ssc:

err_mclk:

	clk_put(mclk);

	mclk = NULL;

err:

	return ret;

}
@@ -320,6 +380,8 @@ static void __exit at91sam9g20ek_exit(void) 


	platform_device_unregister(at91sam9g20ek_snd_device);

	at91sam9g20ek_snd_device = NULL;

	clk_put(mclk);

	mclk = NULL;

}



module_init(at91sam9g20ek_init);