ASoC: fsl_esai: Fix divisor calculation failure at lower ratio

BugLink: http://bugs.launchpad.net/bugs/1778265
commit c656941df9bc80f7ec65b92ca73c42f8b0b62628 upstream.

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>
Tested-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c
index cef79a1a620b7dc3105572e6987c358da8db8a30..81268760b7a9d5435abc43ad17917fcd20908b05 100644 (file)
--- 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;