[PATCH 1/3] ASoC: bdw-rt5677: channel constraint support

[Cezary Rojewski]

On 2020-04-27 10:37, Brent Lu wrote:
> BDW boards using this machine driver supports only stereo capture and
> playback. Implement a constraint to enforce it.
> 

Title for the overall series fits better than the one chosen for actual 
patches. "channel constraint support" is misleading. Constraints are 
added or removed but certainly not supported.

> Signed-off-by: Brent Lu <brent.lu at intel.com>
> ---
>   sound/soc/intel/boards/bdw-rt5677.c | 33 +++++++++++++++++++++++++++++++++
>   1 file changed, 33 insertions(+)
> 
> diff --git a/sound/soc/intel/boards/bdw-rt5677.c b/sound/soc/intel/boards/bdw-rt5677.c
> index cc41a34..7963cae 100644
> --- a/sound/soc/intel/boards/bdw-rt5677.c
> +++ b/sound/soc/intel/boards/bdw-rt5677.c
> @@ -22,6 +22,8 @@
>   
>   #include "../../codecs/rt5677.h"
>   
> +#define DUAL_CHANNEL 2
> +

Remove, we need not additional too-obvious macro. One could argue 
'STEREO' is a better choice too.

>   struct bdw_rt5677_priv {
>   	struct gpio_desc *gpio_hp_en;
>   	struct snd_soc_component *component;
> @@ -222,6 +224,36 @@ static int bdw_rt5677_rtd_init(struct snd_soc_pcm_runtime *rtd)
>   }
>   #endif
>   
> +static const unsigned int channels[] = {
> +	DUAL_CHANNEL,

Inline as stated above.

> +};
> +
> +static const struct snd_pcm_hw_constraint_list constraints_channels = {
> +	.count = ARRAY_SIZE(channels),
> +	.list = channels,
> +	.mask = 0,
> +};
> +
> +static int bdw_fe_startup(struct snd_pcm_substream *substream)

Entire file uses 'bdw_rt5677_' naming convention. Let's not stray away 
from that path now.

> +{
> +	struct snd_pcm_runtime *runtime = substream->runtime;
> +
> +	/*
> +	 * On this platform for PCM device we support,
> +	 * stereo audio
> +	 */

Sometimes you add a newline add and before, while other times just one, 
before the comment. Please streamline the format across all patches in 
the series. Comment can be more strict too
	/* Board supports stereo configuration only */
> +
> +	runtime->hw.channels_max = DUAL_CHANNEL;

Inline. If you really want to avoid using 2, make use of 0-entry of 
constrains_channels array.

> +	snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
> +					   &constraints_channels);
> +
> +	return 0;
> +}
> +
> +static const struct snd_soc_ops bdw_rt5677_fe_ops = {
> +	.startup = bdw_fe_startup,
> +};
> +
>   static int bdw_rt5677_init(struct snd_soc_pcm_runtime *rtd)
>   {
>   	struct bdw_rt5677_priv *bdw_rt5677 =
> @@ -321,6 +353,7 @@ static struct snd_soc_dai_link bdw_rt5677_dais[] = {
>   		},
>   		.dpcm_capture = 1,
>   		.dpcm_playback = 1,
> +		.ops = &bdw_rt5677_fe_ops,
>   		SND_SOC_DAILINK_REG(fe, dummy, platform),
>   	},
>   
>