[XS] Change in coreboot[main]: mb/google/fatcat: Add FW_CONFIG Support for ALC721 soundwire

[Subrata Banik (Code Review)]

Attention is currently required from: Anil Kumar K, Naveen M, Pranava Y N, Varun Upadhyay.

Subrata Banik has posted comments on this change by Varun Upadhyay. ( https://review.coreboot.org/c/coreboot/+/85074?usp=email )

Change subject: mb/google/fatcat: Add FW_CONFIG Support for ALC721 soundwire
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Patch Set 2: Code-Review+2

(1 comment)

File src/mainboard/google/fatcat/variants/fatcat/overridetree.cb:

https://review.coreboot.org/c/coreboot/+/85074/comment/ae39c5ae_b5a8c139?usp... :
PS2, Line 8: AUDIO_ALC721_SNDW
> Yes. This data is important for kernel & ucm.
> Based on codec combination selected in CBI setting, fw_config is expected to configure h/w gpios.

looking at the CBI, I can tell that we cam have either ALC722 or ALC721 therefore, it's either configuration therefore, the GPIO configuration taken care w/o any duplication.
> Kernel acpi match table will use this exposed coreboot data and load specific machine driver

This looks to me little static configuration where we are telling any AIC (and not soldered down module) will be assigned link 3 ? therefore, we need to keep redundant entries for ALC722 and ALC721
> As same machine driver loads multiple codec combinations, config.star in ui/ucm further granularize & applies required mixer setting for that specific codec

and i assume the link and ID numbers are meant to pick the correct mixer settings depending on the Audio codec attached ?