Change in coreboot[master]: mb/google/brya/var/nereid: Add WLAN power sequence

[Reka Norman (Code Review)]

Attention is currently required from: Kangheui Won, Reka Norman, Tim Wawrzynczak.
Hello Sam McNally, Reka Norman, build bot (Jenkins), Kangheui Won, Tim Wawrzynczak,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/63368

to look at the new patch set (#3).

Change subject: mb/google/brya/var/nereid: Add WLAN power sequence
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mb/google/brya/var/nereid: Add WLAN power sequence

There are currently two issues related to the WLAN power sequencing on
nereid:
- If the EN pin GPP_B11 is not high during cold boot, the SoC gets stuck
  in S3.
- During warm reboot, if we only assert RST without pulling the power
  low, then the kernel crashes.

As a workaround while we investigate these issues, we pull the EN high
in S5, then actively drive it low in bootblock and high in romstage to
make sure it goes low during warm reboot.

BUG=b:227694137, b:225261075
TEST=Cold boot succeeds, and there's no kernel crash during warm reboot.

Change-Id: I1ca46d9649eff3f96a0e77db594d87288b29a83a
Signed-off-by: Reka Norman 
---
M src/mainboard/google/brya/variants/nereid/gpio.c
1 file changed, 15 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/68/63368/3