Mine

pcm.!default {
type plug
slave {
pcm multi
rate 48000
}
ttable.0.0 1.0
ttable.1.1 1.0
ttable.0.2 1.0
ttable.1.3 1.0
}

pcm.stereo {
type plug
slave {
pcm multi
rate 48000
}
ttable.0.0 1.0
ttable.1.1 1.0
ttable.0.2 1.0
ttable.1.3 1.0
}

ctl.stereo {
type hw
card 0
}

pcm.multi {
type multi
slaves.a.pcm "analog-hw"
slaves.a.channels 2
slaves.b.pcm "digital-hw"
slaves.b.channels 2
bindings.0.slave a
bindings.0.channel 0
bindings.1.slave a
bindings.1.channel 1
bindings.2.slave b
bindings.2.channel 0
bindings.3.slave b
bindings.3.channel 1
}

ctl.multi {
type hw
card 0
}

pcm.analog-hw {
  type hw
  card 0
  device 0
}

pcm.digital-hw {
  type hw
  card 0
  device 2
}