* Sebastian Reichel sre@kernel.org [200214 13:05]:
On Thu, Feb 13, 2020 at 05:34:54PM -0800, Tony Lindgren wrote:
And bluetooth would be similar to cpcap_audio and mot_mdm6600_audio above.
My understanding is, that CPU is not involved for calls (except for setting up cpcap registers correctly). Basically McBSP3 should remain idle for a call and data goes directly from modem to cpcap. The same should work for modem <-> BT, except that CPCAP seems to always provide the clock. That would imply a direct link between modem and codec / BT?
Yes the direct link is i2s. I'm ot sure if mcbsp can be idle during voice call though, I guess it should be doable since mcbsp is not the clock master :)
My guess is that only cpcap registers and clock rate needs to be changed for bluetooth audio BTW, so if somebody havs a bluetooth headset just do the following in Android:
# cpcaprw --all > /tmp/before configure bluetooth headset for audio in android and start playing some music or make a phone call ... # cpcaprw --all > /tmp/after stop playing music or phone call ... diff -u /tmp/before /tmp/after
The registers will be different for a bluetooth phone call and playing music.
I can provider register values once I find some time.
OK great.
Regards,
Tony