int ad1980_probe (struct ac97_codec * codec, struct ac97_driver * driver);
This entry point is called when a codec is found which matches the driver. At the point it is called the codec is basically operational, mixer operations have been initialised and can be overriden. Called in process context. The field driver_private is available for the driver to use to store stuff.
The caller can claim the device by returning zero, or return a negative error code.