On 5/21/26 10:48, Konrad Dybcio wrote: > On 5/21/26 12:26 AM, Jérôme de Bretagne wrote: >> On 5/20/26 18:40, Jérôme de Bretagne via B4 Relay wrote: >>> From: Jérôme de Bretagne <[email protected]> >>> >>> Add backlight nodes and enable backlight so that it can be controlled >>> with the corresponding buttons found on Surface Pro Type Cover keyboards. >>> >>> The nodes are almost identical to the ones from the ThinkPad X13s with >>> a different enable GPIO for the vreg_edp_bl node. >>> >>> The difference was found by looking at the output of /sys/kernel/debug/gpio >>> on the ThinkPad X13s to see the properties of its enable gpio9: > > [...] > >> and ... backlight still works! It can also be enabled/disabled with: >> /sys/class/backlight/backlight/bl_power >> as expected. >> >> I have no clue why both gpio6 on pmc8280_2 and gpio6 on pmc8280c can enable >> and disable the backlight. Is it a common scenario? > > Could it be that one of them is an ENABLE_BL pin, while the other one > enables the regulator? > > Konrad
I've looked at more device trees and seen that quite a few of them simply don't have a "power-supply = <&vreg_edp_bl>" property in their backlight node. Trying a similar approach, the backlight still works so the gpio6 I was adding wasn't used (or even useful). I will send a simpler patch in v2, removing the power-supply property and the vreg_edp_bl & edp_bl_reg_en nodes. Jérôme
