Re: [RFC PATCH 1/8] ASoC: SDCA: hw_params: program upstream Input Terminals for OT DAI

[Charles Keepax <ckeepax@opensource.cirrus.com>]

On Thu, Jul 23, 2026 at 12:42:11AM +0100, Srinivas Kandagatla wrote:
> For a capture stream the DAI is the Output Terminal so
> sdca_asoc_hw_params() only programs the OT itself: cluster, clock
> and Usage.  The upstream Input Terminals that actually source the
> audio never get their Usage, ClusterIndex or clock programmed, so
> the power domain comes up but no samples are produced.
> 
> Walk the source graph from the OT and program every Input Terminal
> reachable through it.

What was the thinking with respect to the units in the middle?
It's not clear to me things are quite as simple as we can copy the
cluster from the output terminal to the input terminal. Various
entities in the middle could change the cluster, such as CRUs,
MPFUs, UDMPUs. Also possibly SUs to consider too, since they
may change which ITs are actually connected at that point in time,
although potentially an argument to be made that programming the
unconnected ones would have no ill effects I guess.

Any thoughts as well on the propogation of the clock and usage.
Its a little less clear to me from the spec that they are even
intended to propogate in this fashion, although it does seem
fairly logical to me.

Thanks,
Charles