[alsa-devel] Custom IOCTL call

I am writing custom IOCTL calls for my card. I have made hwdep interface and set ioctl ops call for it. But, now the question is which device I need to open in my user space app to talk to correct ioctl? I have tried /dev/snd/controlC0 and /dev/snd/pcmC0D0p Both of theses returned invalid IOCTL. Cheers Ogi