diff mbox

ASoC: atmel_ssc_dai: Match the CMR divider only in full duplex.

Message ID 1414178759-7252-2-git-send-email-peda@axentia.se (mailing list archive)
State New, archived
Headers show

Commit Message

Peter Rosin Oct. 24, 2014, 7:25 p.m. UTC
The CMR divider register is shared by playback and capture. The SSC driver
therefore tries to enforce rules so that the needed register content do
not conflict during simultaneous playback/capture. However, the
implementation also prevents changing the register content in
half-duplex scenarios, which is needed when using the OSS API.

Thus, only lock the divider if there is a stream in the other direction.

Fixes the below program to not fail with the atmel ssc dai in master mode.

#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/soundcard.h>

int
main(void)
{
	int fd;
	int format;
	int channels;
	int speed;

	if ((fd = open("/dev/dsp", O_WRONLY, 0)) == -1) {
		perror("open");
		return 1;
	}
	format = AFMT_S16_LE;
	if (ioctl(fd, SNDCTL_DSP_SETFMT, &format) == -1) {
		perror("SNDCTL_DSP_SETFMT");
		return 1;
	}
	channels = 2;
	if (ioctl(fd, SNDCTL_DSP_CHANNELS, &channels) == -1) {
		perror("SNDCTL_DSP_CHANNELS");
		return 1;
	}
	speed = 22025;
	if (ioctl(fd, SNDCTL_DSP_SPEED, &speed) == -1) {
		perror("SNDCTL_DSP_SPEED");
		return 1;
	}
	return 0;
}

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 sound/soc/atmel/atmel_ssc_dai.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Mark Brown Oct. 31, 2014, 6:12 p.m. UTC | #1
On Fri, Oct 24, 2014 at 09:25:59PM +0200, Peter Rosin wrote:
> The CMR divider register is shared by playback and capture. The SSC driver
> therefore tries to enforce rules so that the needed register content do
> not conflict during simultaneous playback/capture. However, the
> implementation also prevents changing the register content in
> half-duplex scenarios, which is needed when using the OSS API.

Bo, is this OK?
Bo Shen Nov. 3, 2014, 1:25 a.m. UTC | #2
Hi Mark,

On 11/01/2014 02:12 AM, Mark Brown wrote:
> On Fri, Oct 24, 2014 at 09:25:59PM +0200, Peter Rosin wrote:
>> The CMR divider register is shared by playback and capture. The SSC driver
>> therefore tries to enforce rules so that the needed register content do
>> not conflict during simultaneous playback/capture. However, the
>> implementation also prevents changing the register content in
>> half-duplex scenarios, which is needed when using the OSS API.
>
> Bo, is this OK?

I have acked this patch. However Peter resend with "git send-email" 
command while not add Acked-by tag. Anyway:

Acked-by: Bo Shen <voice.shen@atmel.com>

Best Regards,
Bo Shen
Mark Brown Nov. 3, 2014, 12:45 p.m. UTC | #3
On Fri, Oct 24, 2014 at 09:25:59PM +0200, Peter Rosin wrote:
> The CMR divider register is shared by playback and capture. The SSC driver
> therefore tries to enforce rules so that the needed register content do
> not conflict during simultaneous playback/capture. However, the
> implementation also prevents changing the register content in
> half-duplex scenarios, which is needed when using the OSS API.

Applied, thanks.
diff mbox

Patch

diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
index f403f39..b1cc2a4 100644
--- a/sound/soc/atmel/atmel_ssc_dai.c
+++ b/sound/soc/atmel/atmel_ssc_dai.c
@@ -310,7 +310,10 @@  static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
 		 * transmit and receive, so if a value has already
 		 * been set, it must match this value.
 		 */
-		if (ssc_p->cmr_div == 0)
+		if (ssc_p->dir_mask !=
+			(SSC_DIR_MASK_PLAYBACK | SSC_DIR_MASK_CAPTURE))
+			ssc_p->cmr_div = div;
+		else if (ssc_p->cmr_div == 0)
 			ssc_p->cmr_div = div;
 		else
 			if (div != ssc_p->cmr_div)