[alsa-devel] [PATCH v2] ASoC: atmel_ssc_dai: Match the CMR divider only in full duplex.

[Bo Shen]

Hi Peter,
   Thanks for your patch.

   Btw, do you use "git send-email" command to send the patch?

On 10/22/2014 11:13 PM, Peter Rosin wrote:
>  From 86be84c4de4e7b21cfda9656a02a902c543210af Mon Sep 17 00:00:00 2001
> From: Peter Rosin <peda at axentia.se>
> Date: Wed, 22 Oct 2014 16:45:29 +0200
> Subject: [PATCH v2] ASoC: atmel_ssc_dai: Match the CMR divider only in full
>   duplex.
>
> 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 at axentia.se>

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

> ---
>   sound/soc/atmel/atmel_ssc_dai.c |    5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c
> index de433cfd..9ae8475 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)
>

Best Regards,
Bo Shen