ad1843_get_gain
int ad1843_get_gain(struct snd_ad1843 *ad1843, int id);
return ad1843_get_gain(ad1843, id);
vol = ad1843_get_gain(&chip->ad1843, (int)kcontrol->private_value);
oldvol = ad1843_get_gain(&chip->ad1843, kcontrol->private_value);