[alsa-devel] [PATCH] ASoC: Added PCM short and long frame sync formats

[Lars-Peter Clausen]

On 03/27/2012 05:34 AM, Omair Mohammed Abdullah wrote:
> On Tuesday 27 March 2012 09:02 AM, Omair Mohammed Abdullah wrote:
>> The PCM short frame sync sends a short (1 clock length) sync signal before the
>> MSB of data. The PCM long frame sync sends a 1 word length sync signal along
>> with the data.
>>
>> Signed-off-by: Omair Mohammed Abdullah<omair.m.abdullah at linux.intel.com>
>> ---
>>   include/sound/soc-dai.h |    2 ++
>>   1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
>> index c429f24..dc94b25 100644
>> --- a/include/sound/soc-dai.h
>> +++ b/include/sound/soc-dai.h
>> @@ -32,6 +32,8 @@ struct snd_soc_dapm_widget;
>>   #define SND_SOC_DAIFMT_DSP_B		5 /* L data MSB during FRM LRC */
>>   #define SND_SOC_DAIFMT_AC97		6 /* AC97 */
>>   #define SND_SOC_DAIFMT_PDM		7 /* Pulse density modulation */
>> +#define SND_SOC_DAIFMT_SHORT_SYNC	8 /* FRM for 1 clock before MSB */
>> +#define SND_SOC_DAIFMT_LONG_SYNC	9 /* FRM for 1 word starting with MSB */
>>
>>   /* left and right justified also known as MSB and LSB respectively */
>>   #define SND_SOC_DAIFMT_MSB		SND_SOC_DAIFMT_LEFT_J
> 
> What I am looking for is something like this. But 
> SND_SOC_DAIFMT_SHORT_SYNC might be the same as SND_SOC_DAIFMT_DSP_A.

Yes it is. And if you really only have two slots your long sync is
SND_SOC_DAIFMT_LEFT_J, but with the bit clock inverted.