I have seen this chip offered from several chinese distributors. It seems to be fabricated by CRYSTRL, eventually a second, third or even fourth source manufacturer...

This might by the reason why CIRRUS no longer supports this chip by providing a datasheet via web. They would support this chinese company finally...

This can often be seen nowadays. Standard diodes, transistors and chips are no longer fabricated by the good old manufacturers but by hundreds of dubious manufacturers in the far east, finally ruining the prices and the quality.

Good luck,

Kai