[PATCH] ALSA: atmel_abdac: clk_round_rate() can return a zero upon error

[PATCH] ALSA: atmel_abdac: clk_round_rate() can return a zero upon error

[Paul Walmsley]

Treat both negative and zero return values from clk_round_rate()
as errors.  This is needed since subsequent patches will convert
clk_round_rate()'s return value to be an unsigned type, rather
than a signed type, since some clock sources can generate rates higher
than (2^31)-1 Hz.

Eventually, when calling clk_round_rate(), only a return value of
zero will be considered a error; all other values will be
considered valid rates.  The comparison against values less than
0 is kept to preserve the correct behavior in the meantime.

Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
---
Applies on v3.13-rc3.  See also:

http://marc.info/?l=linux-arm-kernel&m=138542591313620&w=2

  sound/atmel/abdac.c |    2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/atmel/abdac.c b/sound/atmel/abdac.c
index 721d8fd..3519518 100644
--- a/sound/atmel/abdac.c
+++ b/sound/atmel/abdac.c
@@ -354,7 +354,7 @@ static int set_sample_rates(struct atmel_abdac *dac)
  	/* we start at 192 kHz and work our way down to 5112 Hz */
  	while (new_rate >= RATE_MIN && index < (MAX_NUM_RATES + 1)) {
  		new_rate = clk_round_rate(dac->sample_clk, 256 * new_rate);
-		if (new_rate < 0)
+		if (new_rate <= 0)
  			break;
  		/* make sure we are below the ABDAC clock */
  		if (index < MAX_NUM_RATES &&

Re: [PATCH] ALSA: atmel_abdac: clk_round_rate() can return a zero upon error

[Hans-Christian Egtvedt]

Around Mon 09 Dec 2013 18:49:13 -0800 or thereabout, Paul Walmsley wrote:
> 
> Treat both negative and zero return values from clk_round_rate()
> as errors.  This is needed since subsequent patches will convert
> clk_round_rate()'s return value to be an unsigned type, rather
> than a signed type, since some clock sources can generate rates higher
> than (2^31)-1 Hz.
> 
> Eventually, when calling clk_round_rate(), only a return value of
> zero will be considered a error; all other values will be
> considered valid rates.  The comparison against values less than
> 0 is kept to preserve the correct behavior in the meantime.
> 
> Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
> Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
> Cc: Takashi Iwai <tiwai@suse.de>
> Cc: Jaroslav Kysela <perex@perex.cz>

Thanks for fixing.

Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>

> ---
> Applies on v3.13-rc3.  See also:
> 
> http://marc.info/?l=linux-arm-kernel&m=138542591313620&w=2
> 
>  sound/atmel/abdac.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/atmel/abdac.c b/sound/atmel/abdac.c
> index 721d8fd..3519518 100644
> --- a/sound/atmel/abdac.c
> +++ b/sound/atmel/abdac.c
> @@ -354,7 +354,7 @@ static int set_sample_rates(struct atmel_abdac *dac)
>  	/* we start at 192 kHz and work our way down to 5112 Hz */
>  	while (new_rate >= RATE_MIN && index < (MAX_NUM_RATES + 1)) {
>  		new_rate = clk_round_rate(dac->sample_clk, 256 * new_rate);
> -		if (new_rate < 0)
> +		if (new_rate <= 0)
>  			break;
>  		/* make sure we are below the ABDAC clock */
>  		if (index < MAX_NUM_RATES &&
> 

-- 
mvh
Hans-Christian Egtvedt