Re: [PATCH] ASoC: Intel: Update bxt_da7219_max98357a to add a new platform clock widget

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 03/02/2017 03:54 PM, Harsha Priya wrote:
> This patch adds a platform clock widget to turn off the clock only when
> both headset capture and headset playback are not in use. This removes
> turning off the clock in hw_free so that the clock is on when
> either capture or playback of headset is in progress.

When the platform_clock widget is used, we typically use the EVENT_ON 
case to turn on the PLL and we turn it off in the EVENT_OFF case.
Here you are turning the PLL on in a .hw_params function and off in a 
EVENT_OFF.
Is this asymmetry required or could the PLL enablement be handled with 
EVENT_ON?

>
> Signed-off-by: Harsha Priya <harshapriya.n@intel.com>
> Signed-off-by: Sathyanarayana Nujella <sathyanarayana.nujella@intel.com>
> ---
>   sound/soc/intel/boards/bxt_da7219_max98357a.c | 58 +++++++++++++++++++--------
>   1 file changed, 41 insertions(+), 17 deletions(-)
>
> diff --git a/sound/soc/intel/boards/bxt_da7219_max98357a.c b/sound/soc/intel/boards/bxt_da7219_max98357a.c
> index 2cda06c..ed58809 100644
> --- a/sound/soc/intel/boards/bxt_da7219_max98357a.c
> +++ b/sound/soc/intel/boards/bxt_da7219_max98357a.c
> @@ -55,6 +55,42 @@ enum {
>   	BXT_DPCM_AUDIO_HDMI3_PB,
>   };
>   
> +static inline struct snd_soc_dai *bxt_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, BXT_DIALOG_CODEC_DAI,
> +			     strlen(BXT_DIALOG_CODEC_DAI)))
> +			return rtd->codec_dai;
> +	}
> +
> +	return NULL;
> +}
> +
> +static int platform_clock_control(struct snd_soc_dapm_widget *w,
> +	struct snd_kcontrol *k, int  event)
> +{
> +	int ret = 0;
> +	struct snd_soc_dapm_context *dapm = w->dapm;
> +	struct snd_soc_card *card = dapm->card;
> +	struct snd_soc_dai *codec_dai;
> +
> +	codec_dai = bxt_get_codec_dai(card);
> +	if (!codec_dai) {
> +		dev_err(card->dev, "Codec dai not found; Unable to stop PLL\n");
> +		return -EIO;
> +	}
> +
> +	if (SND_SOC_DAPM_EVENT_OFF(event)) {
> +		ret = snd_soc_dai_set_pll(codec_dai, 0,
> +			DA7219_SYSCLK_MCLK, 0, 0);
> +	}
> +
> +	return ret;
> +}
> +
>   static const struct snd_kcontrol_new broxton_controls[] = {
>   	SOC_DAPM_PIN_SWITCH("Headphone Jack"),
>   	SOC_DAPM_PIN_SWITCH("Headset Mic"),
> @@ -69,6 +105,8 @@ enum {
>   	SND_SOC_DAPM_SPK("HDMI1", NULL),
>   	SND_SOC_DAPM_SPK("HDMI2", NULL),
>   	SND_SOC_DAPM_SPK("HDMI3", 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 broxton_map[] = {
> @@ -109,6 +147,9 @@ enum {
>   	/* DMIC */
>   	{"dmic01_hifi", NULL, "DMIC01 Rx"},
>   	{"DMIC01 Rx", NULL, "DMIC AIF"},
> +
> +	{ "Headphone Jack", NULL, "Platform Clock" },
> +	{ "Headset Mic", NULL, "Platform Clock" },
>   };
>   
>   static int broxton_ssp_fixup(struct snd_soc_pcm_runtime *rtd,
> @@ -265,25 +306,8 @@ static int broxton_da7219_hw_params(struct snd_pcm_substream *substream,
>   	return ret;
>   }
>   
> -static int broxton_da7219_hw_free(struct snd_pcm_substream *substream)
> -{
> -	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> -	struct snd_soc_dai *codec_dai = rtd->codec_dai;
> -	int ret;
> -
> -	ret = snd_soc_dai_set_pll(codec_dai, 0,
> -			DA7219_SYSCLK_MCLK, 0, 0);
> -	if (ret < 0) {
> -		dev_err(codec_dai->dev, "failed to stop PLL: %d\n", ret);
> -		return -EIO;
> -	}
> -
> -	return ret;
> -}
> -
>   static const struct snd_soc_ops broxton_da7219_ops = {
>   	.hw_params = broxton_da7219_hw_params,
> -	.hw_free = broxton_da7219_hw_free,
>   };
>   
>   static int broxton_dmic_fixup(struct snd_soc_pcm_runtime *rtd,