[alsa-devel] [PATCH v4 1/2] ASoC: core: allow DAI PCM controls bound to PCM device

[Arnaud Pouliquen]

Hi,

Takashi (Sakamoto): Thanks for the remarks, i will integrate them in V5

Liam, Marc, Takashi (Iwai),
I was wondering if you have any comment and/or feedback about this
patch-set. That's would help to determine if i have to continue to
evolve the patch-set in this way, or if you see bocking point in the
concept.

Regards,

Arnaud

On 12/05/2016 12:48 PM, Takashi Sakamoto wrote:
> Hi,
> 
> On Nov 30 2016 19:24, Arnaud Pouliquen wrote:
>> In case of several instances of the same PCM control (e.g IEC controls).
>> Application should be able to address the control using the
>> device field number, according to the PCM character device.
>> This patch allows to link DAI PCM controls to the PCM device.
>> During DAI_link probe, PCM controls are added after device field is forced
>> to the PCM device number.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen at st.com>
>> ---
>>  include/sound/soc-dai.h |  4 ++++
>>  sound/soc/soc-core.c    | 35 +++++++++++++++++++++++++++++++++++
>>  2 files changed, 39 insertions(+)
>>
>> diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
>> index 200e1f0..3ff1a86 100644
>> --- a/include/sound/soc-dai.h
>> +++ b/include/sound/soc-dai.h
>> @@ -273,6 +273,10 @@ struct snd_soc_dai_driver {
>>  	/* probe ordering - for components with runtime dependencies */
>>  	int probe_order;
>>  	int remove_order;
>> +
>> +	/* Optional PCM controls to bind to PCM device on DAIs link*/
> 
> In this patchset, you newly request developers to pay enough attention 
> to 'iface' field of identification information for the control element 
> set. This is logically correct, however such kind of special requirement 
> should be described in code comment for the other developers to start 
> using this feature easily.
> 
>> +	const struct snd_kcontrol_new *pcm_controls;
>> +	int num_pcm_controls;
>>  };
>>
>>  /*
>> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
>> index aaab26a..7b79a31 100644
>> --- a/sound/soc/soc-core.c
>> +++ b/sound/soc/soc-core.c
>> @@ -1598,6 +1598,32 @@ static int soc_probe_dai(struct snd_soc_dai *dai, int order)
>>  	return 0;
>>  }
>>
>> +static int soc_link_dai_pcm_controls(struct snd_soc_dai **dais, int num_dais,
>> +				     struct snd_soc_pcm_runtime *rtd)
>> +{
>> +	struct snd_kcontrol_new kctl;
>> +	int i, j, ret;
>> +
>> +	for (i = 0; i < num_dais; ++i) {
>> +		for (j = 0; j < dais[i]->driver->num_pcm_controls; j++) {
>> +			kctl = dais[i]->driver->pcm_controls[j];
>> +			if (kctl.iface != SNDRV_CTL_ELEM_IFACE_PCM ||
>> +			    rtd->dai_link->no_pcm) {
>> +				dev_err(dais[i]->dev,
>> +					"Failed to bind control: %s\n",
>> +					kctl.name);
> 
> It's better to output name of the DAI driver, to make it easy to 
> identify which driver causes this issue, as well.
> 
>> +				return -EINVAL;
>> +			}
>> +			kctl.device = rtd->pcm->device;
>> +			ret = snd_soc_add_dai_controls(dais[i], &kctl, 1);
>> +			if (ret < 0)
>> +				return ret;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static int soc_link_dai_widgets(struct snd_soc_card *card,
>>  				struct snd_soc_dai_link *dai_link,
>>  				struct snd_soc_pcm_runtime *rtd)
>> @@ -1709,6 +1735,15 @@ static int soc_probe_link_dais(struct snd_soc_card *card,
>>  				       dai_link->stream_name, ret);
>>  				return ret;
>>  			}
>> +
>> +			/* Bind DAIs pcm controls to the PCM device */
>> +			ret = soc_link_dai_pcm_controls(&cpu_dai, 1, rtd);
>> +			if (ret < 0)
>> +				return ret;
>> +			ret = soc_link_dai_pcm_controls(rtd->codec_dais,
>> +							rtd->num_codecs, rtd);
>> +			if (ret < 0)
>> +				return ret;
>>  		} else {
>>  			INIT_DELAYED_WORK(&rtd->delayed_work,
>>  						codec2codec_close_delayed_work);
> 
> Regards
> 
> Takashi Sakamoto
>