Re: [PATCH 2/2] ASoc: Intel: board: add BE DAI link for WoV

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

On 3/24/21 12:52 PM, vamshi.krishna.gopal@intel.com wrote:
> From: Mac Chiang <mac.chiang@intel.com>
> 
> create dai link in kbl_da7219_max98357a driver for wake on voice
> functionality.
> 
> changes picked from broonie's tree
> commit 0c7941a63a0f
> ("ASoC: Intel: Skylake: Use refcap device for mono recording")
> commit 2154be362c90
> ("ASoc: Intel: boards: Add WOV as sink for nau88l25_ssm4567 machine")
> 
> Signed-off-by: Mac Chiang <mac.chiang@intel.com>
> Signed-off-by: Vamshi Krishna Gopal <vamshi.krishna.gopal@intel.com>
> Tested-by: Kaiyen Chang <kaiyen.chang@intel.corp-partner.google.com>
> Tested-by: luke yang <luke_yang@compal.corp-partner.google.com>
> Tested-by: Grace Kao <grace.kao@intel.com>
> Tested-by: Kaiyen Chang <kaiyen.chang@intel.com>
> Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
> ---
>   sound/soc/intel/boards/kbl_da7219_max98357a.c | 35 +++++++++++++++++++
>   1 file changed, 35 insertions(+)
> 
> diff --git a/sound/soc/intel/boards/kbl_da7219_max98357a.c b/sound/soc/intel/boards/kbl_da7219_max98357a.c
> index 1d6b2855874d..c9d83eebf4a8 100644
> --- a/sound/soc/intel/boards/kbl_da7219_max98357a.c
> +++ b/sound/soc/intel/boards/kbl_da7219_max98357a.c
> @@ -44,6 +44,7 @@ struct kbl_codec_private {
>   enum {
>   	KBL_DPCM_AUDIO_PB = 0,
>   	KBL_DPCM_AUDIO_CP,
> +	KBL_DPCM_AUDIO_REF_CP,
>   	KBL_DPCM_AUDIO_DMIC_CP,
>   	KBL_DPCM_AUDIO_HDMI1_PB,
>   	KBL_DPCM_AUDIO_HDMI2_PB,
> @@ -335,12 +336,36 @@ static struct snd_soc_ops kabylake_dmic_ops = {
>   	.startup = kabylake_dmic_startup,
>   };
>   
> +static const struct snd_pcm_hw_constraint_list constraints_refcap = {
> +	.count = ARRAY_SIZE(ch_mono),
> +	.list  = ch_mono,
> +};
> +
> +static int kabylake_refcap_startup(struct snd_pcm_substream *substream)
> +{
> +	substream->runtime->hw.channels_max = 1;
> +	snd_pcm_hw_constraint_list(substream->runtime, 0,
> +					SNDRV_PCM_HW_PARAM_CHANNELS,
> +					&constraints_refcap);
> +
> +	return snd_pcm_hw_constraint_list(substream->runtime, 0,
> +					SNDRV_PCM_HW_PARAM_RATE,
> +					&constraints_16000);
> +}
> +
> +static struct snd_soc_ops skylaye_refcap_ops = {
> +	.startup = kabylake_refcap_startup,
> +};
> +
>   SND_SOC_DAILINK_DEF(dummy,
>   	DAILINK_COMP_ARRAY(COMP_DUMMY()));
>   
>   SND_SOC_DAILINK_DEF(system,
>   	DAILINK_COMP_ARRAY(COMP_CPU("System Pin")));
>   
> +SND_SOC_DAILINK_DEF(reference,
> +	DAILINK_COMP_ARRAY(COMP_CPU("Reference Pin")));
> +
>   SND_SOC_DAILINK_DEF(dmic,
>   	DAILINK_COMP_ARRAY(COMP_CPU("DMIC Pin")));
>   
> @@ -415,6 +440,16 @@ static struct snd_soc_dai_link kabylake_dais[] = {
>   		.ops = &kabylake_da7219_fe_ops,
>   		SND_SOC_DAILINK_REG(system, dummy, platform),
>   	},
> +	[KBL_DPCM_AUDIO_REF_CP] = {
> +		.name = "Kbl Audio Reference cap",
> +		.stream_name = "Wake on Voice",

Does anyone have a clear definition of what "REF_CP" and "reference" 
mean? it's not echo reference since there is a separate entry for this, 
so not sure what the term means.

Half of the SKL/KBL drivers seem to use this FE for "Wake on Voice" and 
the other half use it for 'Refcap', this doesn't look very consistent.

> +		.init = NULL,
> +		.dpcm_capture = 1,
> +		.nonatomic = 1,
> +		.dynamic = 1,
> +		.ops = &skylaye_refcap_ops,
> +		SND_SOC_DAILINK_REG(reference, dummy, platform),
> +	},
>   	[KBL_DPCM_AUDIO_DMIC_CP] = {
>   		.name = "Kbl Audio DMIC cap",
>   		.stream_name = "dmiccap",
>