Re: [alsa-devel] [PATCH v2 3/5] ASoC: core: add support to snd_soc_dai_get_sdw_stream()

[Pierre-Louis Bossart]

On 8/13/19 1:06 PM, Srinivas Kandagatla wrote:
> On 13/08/2019 18:51, Pierre-Louis Bossart wrote:
> > On 8/13/19 11:50 AM, Srinivas Kandagatla wrote:
> > > Thanks for the review,
> > >
> > > On 13/08/2019 15:44, Pierre-Louis Bossart wrote:
> > > > On 8/13/19 3:35 AM, Srinivas Kandagatla wrote:
> > > > > On platforms which have smart speaker amplifiers connected via
> > > > > soundwire and modeled as aux devices in ASoC, in such usecases machine
> > > > > driver should be able to get sdw master stream from dai so that it can
> > > > > use the runtime stream to setup slave streams.
> > > >
> > > > using the _set_sdw_stream? I don't fully get the sequence with the 
> > > > wording above.
> > >
> > > Yes, using set_sdw_stream().
> >
> > Maybe I am missing something here, but I don't see where the 
> > set_sdw_stream() is called.
>
> sorry for the confusion. It was too quick reply. :-)
> I was suppose to say sdw_stream_add_slave() instead of set_sdw_stream().

ok, so get_sdw_stream() and set_sdw_stream() are not meant to be mirrors 
or both implemented. It's just a helper to respectively get a context or 
set a context but a get-modify-set type of operation is not expected.

Do I get this right?

> As Aux device is dailess there is no way to get hold of sdw stream 
> runtime for slave device associated with it.
>
> Having snd_soc_dai_get_sdw_stream() would help machine driver to get 
> hold of sdw_stream_runtime from controller dai and setup slave streams 
> using sdw_stream_add_slave().
>
>
> thanks,
> srini
>
>
> > Also I don't fully get the rule. set_sdw_stream() looks required, 
> > get_sdw_stream() is optional, is this what you are suggesting?
> >
> > > > > soundwire already as a set function, get function would provide more
> > > > > flexibility to above configurations.
> > > >
> > > > I am not clear if you are asking for both to be used, or get only or 
> > > > set only?
> > >
> > > It depends on the usecase, in db845c usecase [1] as Aux device is 
> > > dai less, machine driver is using get function to get hold of master 
> > > stream so that it can setup slave port config.
> > >
> > >
> > > Looks like there is a typo in above like
> > >
> > > This was supposed to be "soundwire already has a set function, get 
> > > function would provide more flexibility to above configurations"
> > >
> > > [1] 
> > > https://git.linaro.org/landing-teams/working/qualcomm/kernel.git/tree/sound/soc/qcom/db845c.c?h=integration-linux-qcomlt 
> > >
> > >
> > > thanks,
> > > srini
> > >
> > > > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > > > > ---
> > > > > Â include/sound/soc-dai.h | 10 ++++++++++
> > > > > Â 1 file changed, 10 insertions(+)
> > > > >
> > > > > diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
> > > > > index dc48fe081a20..1e01f4a302e0 100644
> > > > > --- a/include/sound/soc-dai.h
> > > > > +++ b/include/sound/soc-dai.h
> > > > > @@ -202,6 +202,7 @@ struct snd_soc_dai_ops {
> > > > > ÂÂÂÂÂ int (*set_sdw_stream)(struct snd_soc_dai *dai,
> > > > > ÂÂÂÂÂÂÂÂÂÂÂÂÂ void *stream, int direction);
> > > > > +ÂÂÂ void *(*get_sdw_stream)(struct snd_soc_dai *dai, int direction);
> > > > > ÂÂÂÂÂ /*
> > > > > ÂÂÂÂÂÂ * DAI digital mute - optional.
> > > > > ÂÂÂÂÂÂ * Called by soc-core to minimise any pops.
> > > > > @@ -410,4 +411,13 @@ static inline int 
> > > > > snd_soc_dai_set_sdw_stream(struct snd_soc_dai *dai,
> > > > > ÂÂÂÂÂÂÂÂÂ return -ENOTSUPP;
> > > > > Â }
> > > > > +static inline void *snd_soc_dai_get_sdw_stream(struct snd_soc_dai 
> > > > > *dai,
> > > > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int direction)
> > > > > +{
> > > > > +ÂÂÂ if (dai->driver->ops->get_sdw_stream)
> > > > > +ÂÂÂÂÂÂÂ return dai->driver->ops->get_sdw_stream(dai, direction);
> > > > > +ÂÂÂ else
> > > > > +ÂÂÂÂÂÂÂ return ERR_PTR(-ENOTSUPP);
> > > > > +}
> > > > > +
> > > > > Â #endif
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