Multichannel audio on the ADSP-SC589-EZKit in Linux

It seems the Sound Card Driver for the ADAU1962 only supports 2-channel output, despite having controls for the volume of all 12 DACs.

When I run the command:

speaker-test -D hw:0,0 -c 8 -t sine -F S32_LE

I get an error: "Channels count (8) not available for playbacks: Invalid argument".

Is there anything that can be done to enable 8-channel audio output on this hardware through ALSA?