Re: [PATCH 0/2] ASoC: pcm512x: Add knobs to allow and control overclocking

On Mon, Feb 16, 2015 at 10:02:45PM +0100, Peter Rosin wrote:

Another "feature" that one might want, is that attempts to change the
overclocking should fail with EBUSY when the device is already in use.
But I haven't invested enough time to find out how I should determine
when to fail, so for this version the driver accepts the change but
doesn't enforce the new limit until the clock rates are recalculated.

You should be able to to check for the bias level being set to ON.