you got it right, the RASPA example loopback should be a good starting point for your needs.
It should build easily if you use our cross-compiling SDK and the included CMake project:
With a HiFiBerry, you should get two channel inputs / two channel output in the callback that you can expose to RASPA. It’s a very similar API to ALSA or similar low-level audio HW abstractions framework.
Thanks! Any advice regarding my first questions, regarding setting the hardware parameter options for the inputs?
I can get started with line level input, which may even be more convenient for now as a test signal, but pretty soon I will need to be able to handle both balanced and unbalanced mic input, set gain levels appropriately, etc.
that’s trickier and more a question for @Nitin I guess, who wrote the driver.
That will require some modifications on the driver here:
where right now some of the parameters are hardcoded and will be needed to be exposed as Kernel sysfs parameters. I think it should be possible to get more info by comparing the mainline ALSA driver for the same codec, if that one exposes those kind of controls.
I´ve read this thread since I´m just about ordering a Hifiberry ADC board. I was clearly leaning to the Pro because of its ability to tweak hardware input gain through software (instead of jumpers).
But as I read here… that´s not clear with Elk OS. I know nothing about programming or hacking drivers, so my question here is just: is this feature of Hifiberry ADC Pro already available with Elk OS? If not… Will it be in the near future?