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

[Takashi Iwai]

On Mon, 05 Dec 2016 14:51:23 +0100,
Arnaud Pouliquen wrote:
> 
> 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.

I see no big issue there as the changes look fairly straightforward.


thanks,

Takashi


> 
> 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
> > 
>