linux-kernel - [PATCH linux-next v2] ASoC: adau1373: adau1373_hw

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Message-Id: <1363029503-23880-1-git-send-email-tim.gardner@canonical.com>
Date:	Mon, 11 Mar 2013 13:18:23 -0600
From:	Tim Gardner <tim.gardner@...onical.com>
To:	linux-kernel@...r.kernel.org
Cc:	Tim Gardner <tim.gardner@...onical.com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.de>,
	device-drivers-devel@...ckfin.uclinux.org,
	alsa-devel@...a-project.org
Subject: [PATCH linux-next v2] ASoC: adau1373: adau1373_hw_params: Silence overflow warning

ADAU1373_BCLKDIV_SOURCE is defined as BIT(5) which uses UL constants. On
amd64 the result of the ones complement operator is then truncated to
unsigned int according to the prototype of snd_soc_update_bits(). I think
gcc is correctly warning that the upper 32 bits are lost.

sound/soc/codecs/adau1373.c: In function 'adau1373_hw_params':
sound/soc/codecs/adau1373.c:940:3: warning: large integer implicitly truncated to unsigned type [-Woverflow]

gcc version 4.6.3

Add 2 more BCLKDIV mask macros as explained by Lars:

The BCLKDIV has three fields. The bitclock divider (bit 0-1), the samplerate
(bit 2-4) and the source select (bit 5). Here we want to update the bitclock
divider field and the samplerate field. When I wrote the code I was lazy and
used ~ADAU1373_BCLKDIV_SOURCE as the mask, which for this register is
functionally equivalent to ADAU1373_BCLKDIV_SR_MASK | ADAU1373_BCLKDIV_BCLK_MASK.

Cc: Lars-Peter Clausen <lars@...afoo.de>
Cc: Liam Girdwood <lgirdwood@...il.com>
Cc: Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc: Jaroslav Kysela <perex@...ex.cz>
Cc: Takashi Iwai <tiwai@...e.de>
Cc: device-drivers-devel@...ckfin.uclinux.org
Cc: alsa-devel@...a-project.org
Signed-off-by: Tim Gardner <tim.gardner@...onical.com>
---
v1 - simple cast solution
v2 - Implement a full set of field masks as suggested by Lars.

 sound/soc/codecs/adau1373.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/adau1373.c b/sound/soc/codecs/adau1373.c
index 068b3ae..1aa10dd 100644
--- a/sound/soc/codecs/adau1373.c
+++ b/sound/soc/codecs/adau1373.c
@@ -133,6 +133,8 @@ struct adau1373 {
 #define ADAU1373_DAI_FORMAT_DSP		0x3
 
 #define ADAU1373_BCLKDIV_SOURCE		BIT(5)
+#define ADAU1373_BCLKDIV_SR_MASK	(0x07 << 2)
+#define ADAU1373_BCLKDIV_BCLK_MASK	0x03
 #define ADAU1373_BCLKDIV_32		0x03
 #define ADAU1373_BCLKDIV_64		0x02
 #define ADAU1373_BCLKDIV_128		0x01
@@ -937,7 +939,8 @@ static int adau1373_hw_params(struct snd_pcm_substream *substream,
 	adau1373_dai->enable_src = (div != 0);
 
 	snd_soc_update_bits(codec, ADAU1373_BCLKDIV(dai->id),
-		~ADAU1373_BCLKDIV_SOURCE, (div << 2) | ADAU1373_BCLKDIV_64);
+		ADAU1373_BCLKDIV_SR_MASK | ADAU1373_BCLKDIV_BCLK_MASK,
+		(div << 2) | ADAU1373_BCLKDIV_64);
 
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
-- 
1.7.9.5

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