tree 1eb35a49fcd7963d0eacc36294795b02d78e2061
parent 8317e727ce5d97626d7f59ac515d208502830ad1
author Raul E Rangel <rrangel@chromium.org> 1620243684 -0600
committer Felix Held <felix-coreboot@felixheld.de> 1620343932 +0000

mb/google/guybrush: Switch eSPI ALERT# to in-band

Using the push-pull alert was causing leakages when in S0i3. This is
because the EC drives ALERT#, so when the AP enters S0i3, the extra
current leaks into the SoC and ends up turning on the power regulators.
By using in-band ALERT#, the EC no longer drives this pin high, thus
fixing the leak. We could also have used an open drain alert, but the
rise time is less than ideal.

BUG=b:187122344, b:186135022
TEST=Measure S0i3 power on guybrush and validate it's no longer high.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I6de771aeda8feca062652f0ea9eb57d31cb68562
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52955
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Rob Barnes <robbarnes@google.com>