Since we are using the 'hw' interface of ALSA, we don't have the luxury of
samplerate conversion, given by the 'plughw' interface. If we try to set a
samplerate that is not supported, ALSA will just throw an error.
We can test for the supported samplerates, and create a list of supported
samplerates, then limit the selection to only those values. The frontend can
query the list of supported samplerates.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
The alsa driver only works with device "default". This limits the driver's
scope to whatever device ALSA deems to be "default". It is desirable to have
access to all ALSA devices from sigrok.
Change the alsa device scan so that:
Each alsa device (not alsa card) gets its own sigrok device
For example,
hw:1,0 == sigrok device 0
hw:1,1 == sigrok device 1
hw:2,0 == sigrok device 2
hw:2,1 == sigrok device 3
hw:2,2 == sigrok device 4
[...]
We don't currently look at alsa subdevices. We only use subdevice 0.
Every input device will have its own channels (left, right, etc). Each of
those channels gets mapped to a different sigrok probe. A device with 4
channels will have 4 probes from sigrok's perspective.
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
This is the driver model agreed upon for all drivers.
As a result of the split, a devc->num_probes field had to be added in order to
reduce the interdependence between api.c and protocol.c .
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Uwe Hermann
Bert Vermeulen
Alexandru Gagniuc