[alsa-devel] Common Mode Voltage Setting

[Annaliese McDermond]

I have an architectural question regarding some work I’m doing.  
We have a product that hooks the Raspberry Pi to various amateur 
radio rigs via a sound card interface.  The input characteristics 
of those radios vary widely in the amount of signal they need to 
drive the proper RF output and such.  One of the setting s I’ve 
implemented to try to help our customers control this is changing 
the Common Mode voltage on the tlv320.  There are a couple of 
options, but the gist is that one will allow higher output levels 
without clipping.  We need to keep the flexibility of having the 
lower setting because there are some radios that require as little 
drive as possible.

My question is really surrounding where the appropriate setting 
for this would be.  I could put it in the device tree, but that 
requires adding entries, pushing this past the DT folks and it 
becomes something that a user has to reboot to change settings 
on.  I think it probably more appropriately goes as a mixer 
control so that it can be changed on the fly without reboot
and is a dynamic parameter.

I just want to make sure there’s no strong preference here on 
the “right way” it should be done or if I’m missing a way to 
set this that’s a “none of the above.”

Thanks!

--
Annaliese McDermond
nh6z at nh6z.net