Pioneer DJ DJM mixers channel names

When working on DJM-V10, I noticed that other Pioneer mixers (like my older DJM-250MK2) have control names that do not comply with conventions described at https://docs.kernel.org/sound/designs/control-names.html and thus do not show in alsamixer under proper category (playback/capture) and they are all under playback.

I am preparing a patch that will add "Playback Switch" or "Capture Switch" suffix to control names. But I am not sure about the prefix. Should it be "aux" or "PCM"? It is often the main function, so I tend rather to PCM than auxiliary... Could you give some advice regarding the mixer control names?

Thanks, Franta