How to write a PCM codec device driver with long/short frame sync(Not I2S) in Raspberry Pi? I know how to write an Alsa sound architecture device driver with I2S(write a platform device driver and codec driver) but I suppose raspberry only supports I2S in default.
Finally, I found the answer! PCM has several modes for clocks! I2S is one of the others are DSP Mode A and B, left and right justified and raspbian support all of them.
For the use, another PCM mode is:
1- Codec driver supports it!
2- In the snd_soc_dai_link platform driver, choose them.
More information: I2S DSP modes ,Alsa Device Drivers,DAI hardware audio formats.