tree 3924d886471a4eba18bd9f18ac36712f9f78a659
parent 4ba4911b0ccddfcb54a572ebdfb9b9762c7bce4d
author Nico Huber <nico.huber@secunet.com> 1675949007 +0000
committer Nico Huber <nico.h@gmx.de> 1783945678 +0000

gma broxton: Enable HPD signal inversion

Intel's Apollo Lake uses different hardware for the hotplug-detect
(HPD) input pin. It's not 3.3V tolerant and they changed the design
guide to make the required level shifter also an inverter. To make
the HPD logic reliably detect short and long pulses, the signal needs
to be inverted again, internally, by setting a corresponding bit.

Change-Id: Ia18569d4869d529732fd90d872c2d2c4060c5997
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.sourcearcade.org/c/libgfxinit/+/538
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Thomas Heijligen <src@posteo.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: Nico Huber <nico.h@gmx.de>