On Fri, 25 Apr 2008, Takashi Iwai wrote:

Your driver does _not_ know what type it is because the data isn't
created by your driver but the controller driver.  And, it's free to
attach your driver to any controller.

But controller knows which codec (using ID bytes) is attached, thus it can 
fill appropriate information only for this codec. Of course, it will work 
when only one additional device is sharing bus with codec. See:

http://www.nxp.com/pip/UCB1400-02.html

						Jaroslav

-----
Jaroslav Kysela [off-list ref]
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.