On Mon, 24 May 2021 17:01:50 -0700, Douglas Anderson wrote: > We want to be able to list an eDP panel as a child of an eDP > controller node to represent the fact that the panel is connected to > the controller's DP AUX bus. Though the panel and the controller are > connected in several ways, the DP AUX bus is the primary control > interface between the two and thus makes the most sense to model in > device tree hierarchy. > > Listing a panel in this way makes it possible for the panel driver to > easily get access to the DP AUX bus that it resides on, which can be > useful to help in auto-detecting the panel and for turning on various > bits. > > NOTE: historically eDP panels were _not_ listed under their controller > but were listed at the top level of the device tree. This will still > be supported for backward compatibility (and while DP controller > drivers are adapted to support the new DT syntax) but should be > considered deprecated since there is no downside to listing the panel > under the controller. > > For now, the DP AUX bus bindings will only support an eDP panel > underneath. It's possible it could be extended to allow having a DP > connector under it in the future. > > The idea for this bus's design was hashed out over IRC [1]. > > [1] https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&date=2021-05-11 > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > --- > My DT yaml-fu is still weak. If I did something stupid, please help me > learn how to do this better! > > NOTE: there is no "Example" in this bindings file. Yikes! This is > because I wanted to keep this patch separate from the one that enables > the first eDP controller. See the patch ("dt-bindings: drm/aux-bus: > Add an example") for the example. > > ALSO: if anyone else would like to be listed as a "Maintainer" in this > file then please shout! > > Changes in v8: > - Separate DP AUX bus binding is new for v8. > > .../bindings/display/dp-aux-bus.yaml | 37 +++++++++++++++++++ > 1 file changed, 37 insertions(+) > create mode 100644 Documentation/devicetree/bindings/display/dp-aux-bus.yaml > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
