Hi,

On Thu, Feb 20, 2020 at 04:15:22PM +0200, Peter Ujfalusi wrote:
> > I suppose in the end its a question if generic card can provide TDM
> > support.
> 
> Sure it can, but can it handle the switching between the paths based on
> use cases?
> There should be machine level DAPM widgets to kick codec2codec (MDM6600
> - CPAC_voice for example) and also to make sure that when you switch
> between them the system is not going to get misconfigured.
> Switching between CPAC and BT route during call?
> Not allowing VoIP while on call, etc.

I think the main issue is, that based on the route configuration
(which could be a simple DAPM widget generated by the simple-graph-card),
we may need to configure different bitrates. Tony's hack adding
this knowledge to the cpcap driver is very ugly.

> >> In case of B/C you should not have a running stream imho.
> > 
> > I would expect, that MDM6600 codec marks itself as running/stopped
> > based on call state. That should enable DAPM widgets automatically
> > when CPCAP_voice is routed to MDM6600?
> > 
> >> In all cases CPCAP_voice should be able to run the clocks on i2s,
> >> even if it is not used by the audio setup.
> >> Not sure if you can just turn Wl1285 as master, but it is possible
> >> that it is master, but silent when it is not used?
> > 
> > I provided CPCAP registers for BT call, which should be enough to
> > figure this out (I did not yet analyze the results myself).
> 
> I got the datasheet from NXP (thanks for the pointer!), I try to look at
> it in a coming days.

FWIW the datasheet is not for the same chip, but for a similar one.
The audio part seems to be very similar though.

-- Sebastian