Add some comments describing the hardware pin routing.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

On card models with two-channel outputs, the base driver can
automatically disable the upmixing control so that the model
drivers do not need to do this.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The Essence ST uses the CS2000 chip to generate the DAC master clock, so
we better initialize and program it appropriately.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The virtuoso.c file has become rather big.  This patch splits it up so
that only code for very similar card models is in one file.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>