From 5de7f9b20069257aa5f0bb74723c8603adc5841a Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Mon, 16 Feb 2009 17:51:54 +0000 Subject: [PATCH] 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 Signed-off-by: Mark Brown --- sound/soc/atmel/sam9g20_wm8731.c | 68 ++++++++++++++++++++++++++++++-- 1 file changed, 65 insertions(+), 3 deletions(-) diff --git a/sound/soc/atmel/sam9g20_wm8731.c b/sound/soc/atmel/sam9g20_wm8731.c index b7efdc8119d4..ab32514a858d 100644 --- a/sound/soc/atmel/sam9g20_wm8731.c +++ b/sound/soc/atmel/sam9g20_wm8731.c @@ -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); -- GitLab