| Message ID | 1551333389-22791-1-git-send-email-shengjiu.wang@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ASoC: cs42xx8: Remove S32_LE in format list | expand |
Hi > > cs42xx8 is a 24-bit A/D and 24-bit D/A device, so the S32_LE should > > not be in the supported format list. > > > > Signed-off-by: Shengjiu Wang<shengjiu.wang@nxp.com> > > Is the device capable of accepting 32-bit samples, even if it downgrades it to > 24-bit internally? If so, then maybe SNDRV_PCM_FMTBIT_S32_LE should > stay. Yes, the S32_LE can be accepted by device, it seems like that the device only Use the upper 24bit, so the S32_LE result is same as S24_LE, do you think the S32_LE should be remained? Best regards Wang shengjiu
Hi Shengjiu, On Thu, Feb 28, 2019 at 05:56:31AM +0000, S.j. Wang wrote: > cs42xx8 is a 24-bit A/D and 24-bit D/A device, so the S32_LE > should not be in the supported format list. > > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> > --- > sound/soc/codecs/cs42xx8.c | 3 +-- This is for cs42xx8 codec driver, but its maintainers aren't seemly in To/Cc list. Please run ./scripts/get_maintainer.pl for it and resend.
It would be a mistake to remove S32_LE from the format list. If you removed that, then we wouldn't be able to do 32 bit native playback - it would force users to go through an ALSA plugin. If you look at the cs42448 data sheet for example, the I2S and TDM bus uses a 32 bit word size. For that reason, native S32_LE format is handled by the codec. While the codec only uses the 24 MSBs, the I2S bus is 32 bit. Matt On 1/3/19 3:50 pm, Nicolin Chen wrote: > Hi Shengjiu, > > On Thu, Feb 28, 2019 at 05:56:31AM +0000, S.j. Wang wrote: >> cs42xx8 is a 24-bit A/D and 24-bit D/A device, so the S32_LE >> should not be in the supported format list. >> >> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> >> --- >> sound/soc/codecs/cs42xx8.c | 3 +-- > This is for cs42xx8 codec driver, but its maintainers aren't > seemly in To/Cc list. Please run ./scripts/get_maintainer.pl > for it and resend. > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@alsa-project.org > https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> > It would be a mistake to remove S32_LE from the format list. > > If you removed that, then we wouldn't be able to do 32 bit native playback > - it would force users to go through an ALSA plugin. > > If you look at the cs42448 data sheet for example, the I2S and TDM bus > uses a 32 bit word size. For that reason, native S32_LE format is handled by > the codec. While the codec only uses the 24 MSBs, the I2S bus is 32 bit. This case is covered by S24_LE I think. The S32_LE means the data is 32bit and slot width Is 32bit, this is not in data sheet. Best regards Wang shengjiu > > Matt > > On 1/3/19 3:50 pm, Nicolin Chen wrote: > > Hi Shengjiu, > > > > On Thu, Feb 28, 2019 at 05:56:31AM +0000, S.j. Wang wrote: > >> cs42xx8 is a 24-bit A/D and 24-bit D/A device, so the S32_LE should > >> not be in the supported format list. > >> > >> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> > >> --- > >> sound/soc/codecs/cs42xx8.c | 3 +-- > > This is for cs42xx8 codec driver, but its maintainers aren't seemly in > > To/Cc list. Please run ./scripts/get_maintainer.pl for it and resend. > > _______________________________________________ > > Alsa-devel mailing list > > Alsa-devel@alsa-project.org > > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fma > i > > lman.alsa-project.org%2Fmailman%2Flistinfo%2Falsa- > devel&data=02%7C > > > 01%7Cshengjiu.wang%40nxp.com%7Ce5686d72bd7843c5962508d69e0370a4 > %7C686e > > > a1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7C636870134975623123& > sdata=Rr > > > YwfC4Y3xssED%2FzRum%2FXABGJTHvRrYwnRNgUL7u2lU%3D&reserved > =0
On 3/1/19 12:32 AM, S.j. Wang wrote: > This case is covered by S24_LE I think. The S32_LE means the data is 32bit and slot width > Is 32bit, this is not in data sheet. The problem is that if you have 32-bit samples in your audio file, and you want to play them, then software (e.g. alsalib) will need to convert the audio to 24-bit before sending it to hardware. This is unnecessary because the hardware can "convert" the sample to 24-bit automatically by ignoring the lower 8 bits. I think a lot of codecs do this already.
Hi > On 3/1/19 12:32 AM, S.j. Wang wrote: > > This case is covered by S24_LE I think. The S32_LE means the data is > > 32bit and slot width Is 32bit, this is not in data sheet. > > The problem is that if you have 32-bit samples in your audio file, and you > want to play them, then software (e.g. alsalib) will need to convert the > audio to 24-bit before sending it to hardware. This is unnecessary because > the hardware can "convert" the sample to 24-bit automatically by ignoring > the lower 8 bits. > > I think a lot of codecs do this already. Ok. Thanks for reviewing, I will drop this patch. Best regards Wang shengjiu
diff --git a/sound/soc/codecs/cs42xx8.c b/sound/soc/codecs/cs42xx8.c index ebb9e0cf8364..271972337d23 100644 --- a/sound/soc/codecs/cs42xx8.c +++ b/sound/soc/codecs/cs42xx8.c @@ -32,8 +32,7 @@ #define CS42XX8_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | \ SNDRV_PCM_FMTBIT_S20_3LE | \ - SNDRV_PCM_FMTBIT_S24_LE | \ - SNDRV_PCM_FMTBIT_S32_LE) + SNDRV_PCM_FMTBIT_S24_LE) /* codec private data */ struct cs42xx8_priv {
cs42xx8 is a 24-bit A/D and 24-bit D/A device, so the S32_LE should not be in the supported format list. Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> --- sound/soc/codecs/cs42xx8.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)