Re: [PATCH v3 1/4] ASoC: fsl_asrc: Change asrc_width to asrc_format

From: Shengjiu Wang <shengjiu.wang@gmail.com>
To: Nicolin Chen <nicoleotsuka@gmail.com>
Cc: Shengjiu Wang <shengjiu.wang@nxp.com>,
	Mark Rutland <mark.rutland@arm.com>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux-ALSA <alsa-devel@alsa-project.org>,
	Timur Tabi <timur@kernel.org>, Xiubo Li <Xiubo.Lee@gmail.com>,
	linuxppc-dev@lists.ozlabs.org, Takashi Iwai <tiwai@suse.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Rob Herring <robh+dt@kernel.org>, Mark Brown <broonie@kernel.org>,
	Fabio Estevam <festevam@gmail.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/4] ASoC: fsl_asrc: Change asrc_width to asrc_format
Date: Fri, 28 Feb 2020 10:54:02 +0800	[thread overview]
Message-ID: <CAA+D8AM6t79cPoNmt-8HbGwTSM9bfXSW8g76HtkCF7eauL_Xmw@mail.gmail.com> (raw)
In-Reply-To: <20200227174540.GA17040@Asurada-Nvidia.nvidia.com>

Hi

On Fri, Feb 28, 2020 at 1:45 AM Nicolin Chen <nicoleotsuka@gmail.com> wrote:
>
> On Thu, Feb 27, 2020 at 01:10:19PM +0800, Shengjiu Wang wrote:
> > On Thu, Feb 27, 2020 at 11:43 AM Nicolin Chen <nicoleotsuka@gmail.com> wrote:
> > >
> > > On Thu, Feb 27, 2020 at 10:41:55AM +0800, Shengjiu Wang wrote:
> > > > asrc_format is more inteligent variable, which is align
> > > > with the alsa definition snd_pcm_format_t.
> > > >
> > > > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> > > > ---
> > > >  sound/soc/fsl/fsl_asrc.c     | 23 +++++++++++------------
> > > >  sound/soc/fsl/fsl_asrc.h     |  4 ++--
> > > >  sound/soc/fsl/fsl_asrc_dma.c |  2 +-
> > > >  3 files changed, 14 insertions(+), 15 deletions(-)
> > > >
> > > > diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
> > > > index 0dcebc24c312..2b6a1643573c 100644
> > > > --- a/sound/soc/fsl/fsl_asrc.c
> > > > +++ b/sound/soc/fsl/fsl_asrc.c
> > >
> > > > @@ -600,11 +599,6 @@ static int fsl_asrc_dai_hw_params(struct snd_pcm_substream *substream,
> > > >
> > > >       pair->config = &config;
> > > >
> > > > -     if (asrc_priv->asrc_width == 16)
> > > > -             format = SNDRV_PCM_FORMAT_S16_LE;
> > > > -     else
> > > > -             format = SNDRV_PCM_FORMAT_S24_LE;
> > >
> > > It feels better to me that we have format settings in hw_params().
> > >
> > > Why not let fsl_easrc align with this? Any reason that I'm missing?
> >
> > because the asrc_width is not formal,  in the future we can direct
>
> Hmm..that's our DT binding. And I don't feel it is a problem
> to be ASoC irrelative.
>
> > input the format from the dts. format involve the info about width.
>
> Is there such any formal ASoC binding? I don't see those PCM
> formats under include/dt-bindings/ folder. How are we going
> to involve those formats in DT?

There is no formal binding of this case.

I think it is not good to convert width to format, because, for example
width = 24,  there is two option, we can select format S24_LE,  or
format S24_3LE,  width is ambiguous for selecting.

In EASRC, it support other two 24bit format U24_LE, U24_3LE .

if we use the format in DT, then it is clear for usage in driver.

best regards
wang shengjiu