On Mon, Jun 7, 2021 at 7:06 PM Douglas Anderson <dianders@xxxxxxxxxxxx> 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. > > NOTE: there is no "Example" in this bindings file. Yikes! This avoids > duplicating the same example lots of places. See users of the aux bus > (like ti-sn65dsi86) for examples. > > 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> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> I overall like this approach a lot: Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Yours, Linus Walleij
