[alsa-devel] [PATCH] ASoC: Intel: use 19.2 MCLK instead of the bit clock for bytcr_rt5651.c machine driver

[Pierre-Louis Bossart]

On 6/3/16 10:33 AM, Pietro Di Costanzo wrote:
> Use the MCLK to solve audio quality issues found on some Cherryview-based platforms
>
> Signed-off-by: Pietro Di Costanzo <pxpert at gmail.com>

Thanks Pietro.
this can't be merged as is as it wouldn't work on Baytrail platforms. I 
will merge it with the clock driver we are working to have a single 
driver that works for both cases.

> ---
>  sound/soc/intel/boards/bytcr_rt5651.c | 84 +++++++++++++++++++++++++++++++----
>  1 file changed, 75 insertions(+), 9 deletions(-)
>
> diff --git a/sound/soc/intel/boards/bytcr_rt5651.c b/sound/soc/intel/boards/bytcr_rt5651.c
> index 35f591e..e51ea5b 100644
> --- a/sound/soc/intel/boards/bytcr_rt5651.c
> +++ b/sound/soc/intel/boards/bytcr_rt5651.c
> @@ -31,11 +31,76 @@
>  #include "../../codecs/rt5651.h"
>  #include "../atom/sst-atom-controls.h"
>
> +#define CHT_PLAT_CLK_3_HZ       19200000
> +#define CHT_CODEC_DAI_5651   "rt5651-aif1"
> +
> +struct cht_acpi_card {
> +	char *codec_id;
> +	int codec_type;
> +	struct snd_soc_card *soc_card;
> +};
> +
> +struct cht_mc_private {
> +	struct snd_soc_jack jack;
> +	struct cht_acpi_card *acpi_card;
> +};
> +
> +
> +static inline struct snd_soc_dai *cht_get_codec_dai(struct snd_soc_card *card)
> +{
> +	struct snd_soc_pcm_runtime *rtd;
> +
> +	list_for_each_entry(rtd, &card->rtd_list, list) {
> +		if (!strncmp(rtd->codec_dai->name, CHT_CODEC_DAI_5651,
> +			  strlen(CHT_CODEC_DAI_5651)))
> +			return rtd->codec_dai;
> +	}
> +	return NULL;
> +}
> +
> +static int platform_clock_control(struct snd_soc_dapm_widget *w,
> +		struct snd_kcontrol *k, int  event)
> +{
> +	struct snd_soc_dapm_context *dapm = w->dapm;
> +	struct snd_soc_card *card = dapm->card;
> +	struct snd_soc_dai *codec_dai;
> +	int ret;
> +
> +	codec_dai = cht_get_codec_dai(card);
> +	if (!codec_dai) {
> +		dev_err(card->dev, "Codec dai not found; Unable to set platform clock\n");
> +		return -EIO;
> +	}
> +
> +	if (!SND_SOC_DAPM_EVENT_OFF(event))
> +		return 0;
> +
> +	/* Set codec sysclk source to its internal clock because codec PLL will
> +	 * be off when idle and MCLK will also be off by ACPI when codec is
> +	 * runtime suspended. Codec needs clock for jack detection and button
> +	 * press.
> +	 */
> +	ret = snd_soc_dai_set_sysclk(codec_dai, RT5651_SCLK_S_RCCLK,
> +			0, SND_SOC_CLOCK_IN);
> +	if (ret < 0) {
> +		dev_err(card->dev, "can't set codec sysclk: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +
> +
> +
>  static const struct snd_soc_dapm_widget byt_rt5651_widgets[] = {
>  	SND_SOC_DAPM_HP("Headphone", NULL),
>  	SND_SOC_DAPM_MIC("Headset Mic", NULL),
>  	SND_SOC_DAPM_MIC("Internal Mic", NULL),
>  	SND_SOC_DAPM_SPK("Speaker", NULL),
> +	SND_SOC_DAPM_SUPPLY("Platform Clock", SND_SOC_NOPM, 0, 0,
> +			platform_clock_control, SND_SOC_DAPM_POST_PMD),
> +
>  };
>
>  static const struct snd_soc_dapm_route byt_rt5651_audio_map[] = {
> @@ -52,6 +117,9 @@ static const struct snd_soc_dapm_route byt_rt5651_audio_map[] = {
>  	{"Headphone", NULL, "HPOR"},
>  	{"Speaker", NULL, "LOUTL"},
>  	{"Speaker", NULL, "LOUTR"},
> +	{"Headphone", NULL, "Platform Clock"},
> +	{"Speaker", NULL, "Platform Clock"},
> +
>  };
>
>  static const struct snd_soc_dapm_route byt_rt5651_intmic_dmic1_map[] = {
> @@ -93,7 +161,13 @@ static int byt_rt5651_aif1_hw_params(struct snd_pcm_substream *substream,
>  	struct snd_soc_dai *codec_dai = rtd->codec_dai;
>  	int ret;
>
> -	snd_soc_dai_set_bclk_ratio(codec_dai, 50);
> +	/* set codec PLL source to the 19.2MHz platform clock (MCLK) */
> +	ret = snd_soc_dai_set_pll(codec_dai, 0, RT5651_PLL1_S_MCLK,
> +				  CHT_PLAT_CLK_3_HZ, params_rate(params) * 512);
> +	if (ret < 0) {
> +		dev_err(rtd->dev, "can't set codec pll: %d\n", ret);
> +		return ret;
> +	}
>
>  	ret = snd_soc_dai_set_sysclk(codec_dai, RT5651_SCLK_S_PLL1,
>  				     params_rate(params) * 512,
> @@ -103,14 +177,6 @@ static int byt_rt5651_aif1_hw_params(struct snd_pcm_substream *substream,
>  		return ret;
>  	}
>
> -	ret = snd_soc_dai_set_pll(codec_dai, 0, RT5651_PLL1_S_BCLK1,
> -				  params_rate(params) * 50,
> -				  params_rate(params) * 512);
> -	if (ret < 0) {
> -		dev_err(rtd->dev, "can't set codec pll: %d\n", ret);
> -		return ret;
> -	}
> -
>  	return 0;
>  }
>
>