| Message ID | 1523231855-7854-1-git-send-email-nicoleotsuka@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | ASoC: fsl_esai: Fix divisor calculation failure at lower ratio | expand |
Hi Nicolin, On Sun, Apr 8, 2018 at 8:57 PM, Nicolin Chen <nicoleotsuka@gmail.com> wrote: > When the desired ratio is less than 256, the savesub (tolerance) > in the calculation would become 0. This will then fail the loop- > search immediately without reporting any errors. > > But if the ratio is smaller enough, there is no need to calculate > the tolerance because PM divisor alone is enough to get the ratio. > > So a simple fix could be just to set PM directly instead of going > into the loop-search. > > Reported-by: Marek Vasut <marex@denx.de> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> > Cc: Marek Vasut <marex@denx.de> If this fixes Marek's usecase then I think we should also add: Cc: <stable@vger.kernel.org> Thanks
On 04/09/2018 01:57 AM, Nicolin Chen wrote: > When the desired ratio is less than 256, the savesub (tolerance) > in the calculation would become 0. This will then fail the loop- > search immediately without reporting any errors. > > But if the ratio is smaller enough, there is no need to calculate > the tolerance because PM divisor alone is enough to get the ratio. > > So a simple fix could be just to set PM directly instead of going > into the loop-search. > > Reported-by: Marek Vasut <marex@denx.de> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> > Cc: Marek Vasut <marex@denx.de> On i.MX6Q with TI PCM1808 Tested-by: Marek Vasut <marex@denx.de> > --- > sound/soc/fsl/fsl_esai.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c > index 40a7004..da8fd98 100644 > --- a/sound/soc/fsl/fsl_esai.c > +++ b/sound/soc/fsl/fsl_esai.c > @@ -144,6 +144,13 @@ static int fsl_esai_divisor_cal(struct snd_soc_dai *dai, bool tx, u32 ratio, > > psr = ratio <= 256 * maxfp ? ESAI_xCCR_xPSR_BYPASS : ESAI_xCCR_xPSR_DIV8; > > + /* Do not loop-search if PM (1 ~ 256) alone can serve the ratio */ > + if (ratio <= 256) { > + pm = ratio; > + fp = 1; > + goto out; > + } > + > /* Set the max fluctuation -- 0.1% of the max devisor */ > savesub = (psr ? 1 : 8) * 256 * maxfp / 1000; > >
Hi Nicolin, On Sun, Apr 8, 2018 at 8:57 PM, Nicolin Chen <nicoleotsuka@gmail.com> wrote: > When the desired ratio is less than 256, the savesub (tolerance) > in the calculation would become 0. This will then fail the loop- > search immediately without reporting any errors. > > But if the ratio is smaller enough, there is no need to calculate > the tolerance because PM divisor alone is enough to get the ratio. > > So a simple fix could be just to set PM directly instead of going > into the loop-search. > > Reported-by: Marek Vasut <marex@denx.de> > Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> > Cc: Marek Vasut <marex@denx.de> Thanks for the fix: Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c index 40a7004..da8fd98 100644 --- a/sound/soc/fsl/fsl_esai.c +++ b/sound/soc/fsl/fsl_esai.c @@ -144,6 +144,13 @@ static int fsl_esai_divisor_cal(struct snd_soc_dai *dai, bool tx, u32 ratio, psr = ratio <= 256 * maxfp ? ESAI_xCCR_xPSR_BYPASS : ESAI_xCCR_xPSR_DIV8; + /* Do not loop-search if PM (1 ~ 256) alone can serve the ratio */ + if (ratio <= 256) { + pm = ratio; + fp = 1; + goto out; + } + /* Set the max fluctuation -- 0.1% of the max devisor */ savesub = (psr ? 1 : 8) * 256 * maxfp / 1000;
When the desired ratio is less than 256, the savesub (tolerance) in the calculation would become 0. This will then fail the loop- search immediately without reporting any errors. But if the ratio is smaller enough, there is no need to calculate the tolerance because PM divisor alone is enough to get the ratio. So a simple fix could be just to set PM directly instead of going into the loop-search. Reported-by: Marek Vasut <marex@denx.de> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Cc: Marek Vasut <marex@denx.de> --- sound/soc/fsl/fsl_esai.c | 7 +++++++ 1 file changed, 7 insertions(+)