linux-kernel - [PATCH] ASoC:pcm512x: Fix divide by zero issue.

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Message-Id: <1426886025-10731-1-git-send-email-hm@hmbedded.co.uk>
Date:	Fri, 20 Mar 2015 21:13:45 +0000
From:	Howard Mitchell <hm@...edded.co.uk>
To:	broonie@...nel.org, peda@...ntia.se
Cc:	tiwai@...e.de, lgirdwood@...il.com, perex@...ex.cz, corbet@....net,
	alsa-devel@...a-project.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, Howard Mitchell <hm@...edded.co.uk>
Subject: [PATCH] ASoC:pcm512x: Fix divide by zero issue.

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

diff --git a/sound/soc/codecs/pcm512x.c b/sound/soc/codecs/pcm512x.c
index 5301c4a..8472099 100644
--- a/sound/soc/codecs/pcm512x.c
+++ b/sound/soc/codecs/pcm512x.c
@@ -713,8 +713,8 @@ static int pcm512x_find_pll_coeff(struct snd_soc_dai *dai,
 
 	/* 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);
 
-- 
1.7.9.5

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