[alsa-devel] [PATCH] ASoC: adau1373: adau1373_hw_params: Silence overflow warning

[Lars-Peter Clausen]

On 03/10/2013 06:34 PM, Tim Gardner wrote:
> 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
> 
> Cc: Lars-Peter Clausen <lars at metafoo.de>
> Cc: Liam Girdwood <lgirdwood at gmail.com>
> Cc: Mark Brown <broonie at opensource.wolfsonmicro.com>
> Cc: Jaroslav Kysela <perex at perex.cz>
> Cc: Takashi Iwai <tiwai at suse.de>
> Cc: device-drivers-devel at blackfin.uclinux.org
> Cc: alsa-devel at alsa-project.org
> Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
> ---
>  sound/soc/codecs/adau1373.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/adau1373.c b/sound/soc/codecs/adau1373.c
> index 068b3ae..56ed788 100644
> --- a/sound/soc/codecs/adau1373.c
> +++ b/sound/soc/codecs/adau1373.c
> @@ -132,7 +132,7 @@ struct adau1373 {
>  #define ADAU1373_DAI_FORMAT_I2S		0x2
>  #define ADAU1373_DAI_FORMAT_DSP		0x3
>  
> -#define ADAU1373_BCLKDIV_SOURCE		BIT(5)
> +#define ADAU1373_BCLKDIV_SOURCE		(unsigned int)BIT(5)

Hm, that's a bit ugly. How about the following instead:

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: