Also from the source code, the kernel device driver for the cs4231a is currently
set up for a choice of three sample rates:

Quote:

static struct { short samplerate; char setup; } samplerates[]={
{ 11025, 0x0d },
{ 22050, 0x0c },
{ 29400, 0x0a },
{ 0, 0 } };

The usual rate used for visuals is 29.4KHz, Stereo, 16-bits/channel.
Not quite CD-Audio, but sufficiently good for high-quality radio in an automobile.

I don't know if there's a hardware crystal/clock limit that prevents even
better rates or not, but that should be simple enough to determine from
anyone with schematics, or from tracing signals on the PCB.

Cheers