Alexandre BOUIN wrote:

We have an issue : when we play a right channel stereo track, sound is played on right channel, but sometimes on left. This issue could happen right after starting kernel, or later after 10-20 sounds played.

I've had a similar problem. In my case, the clock from the codec to the chip was unstable. When I attached a 5pF capacitor to it, the clock stabilized and the problem went away.

Try using a probe to validate the clock signal.