Audio output problems through the rt5651 codec using the main line kernel.

I am still trying unsuccessfully to get the sound through the rt5651 codec using the main line kernel (I use NanoPC-T4). I corrected the dts/dtb file and assembled the kernel module. The kernel performs i2s bus and codec switching. The corresponding audio device appears on the system. I start a alsamixer. I can change settings. When I change some settings, I can even hear clicks in the dynamic. So the codec chip is powered up. And the codec chip is controlled through the i2c bus. I can switch the audio output through the codec. But there is no sound. I can 't figure out what the reason is. The dts/dtb files for main line kernel and rockchip 4.4.xxx kernel are slightly different. But I don 't see any criticism. Maybe I can 't understand that. The kernel generates several error messages when initializing the audio sub-system. But in my opinion, these mistakes are not critical. It seems that the audio stream is not going on the i2s bus connected to codec. Or the codec chip does not receive the stream. Give advice. What else can I check?