On 04/20/2016 10:51 AM, Petr Kulhavy wrote:
On 20.04.2016 10:33, Lars-Peter Clausen wrote:
On 04/20/2016 10:03 AM, Petr Kulhavy wrote:
Hello,
I'm writing a driver for ASoC "sound card" hardware which uses CPU GPIO to mute/unmute an analogue amplifier and another GPIO to control an analogue switch for line/mic switching. Is there an abstraction in ALSA to model this kind of hardware?
There is no abstraction. Use controls and/or DAPM and the standard GPIO API, if you grep the sources you'll find a few examples of drivers using GPIOs to mute amplifiers and similar (e.g. qi_lb60).
- Lars
Thanks, Lars, for the good pointers! I will check that out.
Is there also a way to map GPIO to a control which then appears e.g. in alsamixer? That would be useful for the mic/line selection.
Rather than exposing the GPIO itself you'd expose the logical function of the GPIO. E.g. in your case a ENUM control that allows to switch between microphone and capture and in the background this sets the GPIO according to the selection.
- Lars