Default clock speed between STM32MP157-DK1 and CS42l51 codec, and how to change the clock from software to hardware and vice versa.

[PSing.6]

I'm using STM32MP157A-DK1 development board, in this we are using it for audio application,

I'm porting stlinux in the board by yocto BSP.

I wanted to know the codec(CS42l51) available on the board at what default clock it is operating and is it using software clock or hardware clock.

And if it is Software what are the files responsible for clock freq. change.

and also what is the method to change the clock from internal to external and vice versa.