The iPAQ hx4700 machine driver needs a hx4700-audio platform device which is not (yet) merged. The patchs was post on LKML: https://lkml.org/lkml/2011/5/18/222 but [PATCH v3 3/3] pxa/hx4700: add platform device and I2C info for AK4641 codec is missed. Regards, Axel