[alsa-devel] On mixer controls naming

[R. Lemos]

Hi,

I'm trying to write a new driver for a virtual sound card. It isn't
actually a sound card, but only a software solution to control volume
and bass of an external device (using SPI and GPIO). So it only has a
mixer (no pcm or capture subdevices).

I could successfully configure two controls "Master Playback Switch"
and "Master Playback Volume". Alsamixer shows them correctly under
"Playback" view (and very nicely it joined them together to form a
single composite control "Master")

The other control I've named "Tone Control - Bass", as indicated in
writing-an-alsa-driver.pdf. But alsamixer shows it under both
"Playback" and "Capture" views.

How can I restrict this latter control to just playback?

-- 
[]'s
Rodrigo