[alsa-devel] [PATCH 2/2] ASoc: wm8731: add normal mode with 12MHz XTAL

[Charles Keepax]

On Sun, Jun 12, 2016 at 01:22:26PM +1000, Matt Flax wrote:
> It appears that my logic here is flawed.
> From what I can tell, it isn't possible to get a suitable bit clock out of
> the codec when using a 12 MHz crystal. For that reason, in my hardware I
> will change crystals from 12 MHz.

This looks correct the chip only has simple dividers so you won't
be able to get a good audio rate clock from a 12MHz crystal.

> 
> I just want to check ... are there any versions of this codec which output
> the bit clock when in USB mode on the BCLK pin ?
> 

Apologies I am not quite sure I follow what USB mode is in this
context, and the bit clock surely always comes out of the BCLK
pin. Do you simply mean a system with a clock speed that
relates to the 48MHz USB clock, such as your 12MHz? Basically any
part that has a PLL/FLL should work for that, for example the
wm8998:

http://www.cirrus.com/en/products/pro/detail/P1265.html

Thanks,
Charles