[PATCH 4.0 153/220] ASoC: pcm512x: Fix divide by zero issue

From: Greg Kroah-Hartman
Date: Sat May 02 2015 - 17:07:15 EST


4.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Howard Mitchell <hm@xxxxxxxxxxxxxx>

commit f073faa73626f41db7050a69edd5074c53ce6d6c upstream.

If den=1 and pllin_rate>20MHz then den and num are adjusted to 0
causing a divide by zero error a few lines further on. Therefore
this patch correctly scales num and den such that
pllin_rate/den < 20MHz as required in the device data sheet.

Signed-off-by: Howard Mitchell <hm@xxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
sound/soc/codecs/pcm512x.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/soc/codecs/pcm512x.c
+++ b/sound/soc/codecs/pcm512x.c
@@ -576,8 +576,8 @@ static int pcm512x_find_pll_coeff(struct

/* pllin_rate / P (or here, den) cannot be greater than 20 MHz */
if (pllin_rate / den > 20000000 && num < 8) {
- num *= 20000000 / (pllin_rate / den);
- den *= 20000000 / (pllin_rate / den);
+ num *= DIV_ROUND_UP(pllin_rate / den, 20000000);
+ den *= DIV_ROUND_UP(pllin_rate / den, 20000000);
}
dev_dbg(dev, "num / den = %lu / %lu\n", num, den);



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