> Date: Tue, 24 Jan 2023 22:19:09 +0000 > From: Rayyan Ansari <rayyan@xxxxxxxxx> > > On 23/01/2023 17:53, Rob Herring wrote: > > On Sun, Jan 22, 2023 at 05:25:38PM +0000, Rayyan Ansari wrote: > >> On 22/01/2023 15:36, Rob Herring wrote: > >>> On Sat, Jan 21, 2023 at 9:36 AM Rayyan Ansari <rayyan@xxxxxxxxx> wrote: > >>>> > >>> > >>> Why do you need this change? > >>> > >>> The 'simple-framebuffer' contains data on how the bootloader > >>> configured the display. The bootloader doesn't configure the display > >>> size, so this information doesn't belong here. The information should > >>> already be in the panel node, so also no point in duplicating it here. > >>> > >>>> Signed-off-by: Rayyan Ansari <rayyan@xxxxxxxxx> > >>>> --- > >>>> .../devicetree/bindings/display/simple-framebuffer.yaml | 8 ++++++++ > >>>> 1 file changed, 8 insertions(+) > >> > >> Hi Rob, > >> > >> There is the usecase that Hans has mentioned, but I have also mentioned > >> another usecase previously. > >> > >> Adding the width-mm and height-mm properties allows user interfaces such as > >> Phosh (https://puri.sm/posts/phosh-overview/) to scale correctly to the > >> screen. In my case, a panel node is not available and the aforementioned > >> interface is in fact running on the SimpleDRM driver (which binds to the > >> simple-framebuffer device). > > > > Why is the panel node not available? Why not add it? Presumably it is > > not there because you aren't (yet) using the simple-panel driver (and > > others that would need). But presumably you will eventually as I'd > > imagine turning the screen off and back on might be a desired feature. > > It requires more than using the simple-panel driver: first the SoC side > display hardware needs to be brought up, then a panel driver that > implements the proper DCS initialisation sequence needs to be written > (which is currently not fully known). You don't really need a driver. You can just lookup the panel node from your simple-framebuffer driver and get the values of the properties there.
