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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: Sedji Gaouaou <sedji.gaouaou@atmel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Mark Brown 2009-02-16 17:51:54 +00:00
parent 40135ea071
commit 5de7f9b200
1 changed files with 65 additions and 3 deletions
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68
sound/soc/atmel/sam9g20_wm8731.c
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@ -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);