On Fri, Sep 25, 2020 at 10:43:59AM +0900, Kuninori Morimoto wrote:
But multi-Codec side is difficult. Because it is selected via "endpoint" via CPU. No way to select it via "port" and/or "ports".
Indeed.
We might want to select Multi-CPU/Codec by using multi deivces ? in such case, using "ports" idea is not enough.
Using extra device like DSP can be more generic ?
<--- multi-CPU ---> ******* CPU0-1 <--> * * <--> Codec0 CPU0-2 <--> * * CPU0-3 <--> * * *******
I think this is what we want for SoCs, represent the DSPs explicitly and then have the FEs and BEs all be ports on the DSP. I think a similar thing would also work for legacy (I2S & so on) DAIs where we've got more endpoints on the DAI - if we define slots on the DAI then from the point of view of the DT bindings it's just a very, very inflexible DSP:
CPU1 <--> DAI slot A <--> Codec1-1 -> DAI slot B <--> Codec1-2 CPU2 <--> DAI slot C <--> Codec1-3
or whatever. This doesn't allow for really complex setups that change the slot mapping at runtime (TBH those probably need custom cards anyway) but I think it should support most cases where TDM causes difficulties today. I'm not sure if we need this for more modern buses like SoundWire, I'd hope we can dynamically assign slots at runtime more easily, but ICBW.
Thanks for all your work on this!