On Thu, Jun 11, 2026 at 1:36 PM Icenowy Zheng <[email protected]> wrote: > > 在 2026-06-11四的 13:26 +0800，Pengyu Luo写道： > > On Tue, 09 Jun 2026 00:26:20 +0800, Icenowy Zheng > > <[email protected]> wrote: > > > When the backlight is managed by the panel controller IC, an > > > external > > > power rail might be powering the backlight. > > > > > > Add an optional `bl-supply` property to describe such power rail, > > > thus > > > allow disabling the backlight. > > > > > > > Please add it as a hwen pin, this will simplify your code later. > > I am not sure whether this should be a pin or a regulator -- the DT > binding should reflect the HW fact, and LCD panel backlights usually > require a high voltage (or even a current source) that is driven by a > dedicated regulator. >
Most backlight ICs use a hwen pin to enable the supply, afaik, like ktz8866, ktz8868, aw99706, etc. We don't touch the VIN. (My disclaimer: I am just an amateur, know less about the circuit) Best wishes, Pengyu > Thanks, > Icenowy > > > > > > > > > > > > diff --git > > > a/Documentation/devicetree/bindings/display/panel/himax,hx83121a.ya > > > ml > > > b/Documentation/devicetree/bindings/display/panel/himax,hx83121a.ya > > > ml > > > index e067a2f6d0b2..aeca3c9a599c 100644 > > > --- > > > a/Documentation/devicetree/bindings/display/panel/himax,hx83121a.ya > > > ml > > > +++ > > > b/Documentation/devicetree/bindings/display/panel/himax,hx83121a.ya > > > ml > > > @@ -40,6 +40,9 @@ properties: > > > vddi-supply: > > > description: power supply for IC > > > > > > + bl-supply: > > > + description: power supply for backlight, in case it's managed > > > via DSC > > > + > > > > s/DSC/DCS/ > > > > Best wishes, > > Pengyu >
