Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/34705 )
Change subject: mb/google/helios: Set SPKR_PA_EN PIN high for boot beep ......................................................................
Patch Set 2:
Patch Set 1:
Patch Set 1: Code-Review+2
Patch Set 1:
Patch Set 1:
Does it need to be enabled in coreboot or can the bootloader apply it?
I guess you mean to say "depthchage" when you are referring "can the bootloader apply it?" yes, DC can also do it and i don't believe it has my given timing sequence that SPKR_EN has to be enable "n" ms before sending i2C data and clock. Although we haven't tried moving that code into payload, i'm not big fan of doing GPIO programming in payload :), but certainly can be verified before sending init sequence to codec.
Adding to the question asked by Tim: Is this pin set to high only for boot beep? Or is it required later on for OS operation as well? If this is just for boot beep, then it should be set to low here and set high in depthcharge.
Furquan, as per my understanding this PIN should set to high for SPKR to work but looks like by some mean Kernel might able to play with it, we can dump this GPIO in kernel space and see the status. But as Satya had already mentioned that setting this GPIO to High doesn't cause any side effect for OS audio to work. He is still investigating about SPKR_EN PIN behavior from kernel space.