ASoC: fsl_esai: Fix divisor calculation failure at lower ratio

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>

diff --git a/sound/soc/fsl/fsl_esai.c b/sound/soc/fsl/fsl_esai.c
index 38bfd46f4ad8c3898d376d94d9f5bd010e285139..3ef174531344548adf66d585b086bd1f175f81d0 100644 (file)
--- a/sound/soc/fsl/fsl_esai.c
+++ b/sound/soc/fsl/fsl_esai.c
@@ -145,6 +145,13 @@ 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;