There are two ways to control backlight in geralt:
1. MIPI/eDP panel => control backlight via the GPIOs.
(`backlight chip enable` and `PWM dimming control`)
2. eDP OLED panel => enable backlight via `backlight chip enable` and
control dimming over AUX.
For MIPI/eDP panels(#1), both "backlight enable" and "PWM control" GPIOs
will be passed from coreboot. For eDP OLED panel(#2), only the
"backlight enable" GPIO will be passed. If depthcharge successfully gets
the GPIOs, it will use them to control backlight.
BUG=b:244208960
TEST=test firmware display pass for eDP and MIPI panels on MT8188 EVB
Change-Id: I866fa219722241008e2b0d566b29edf2f6d9321f
Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70744
Reviewed-by: Yidi Lin <yidilin@google.com>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
f57155bca4