Messages in this thread | | | Date | Fri, 01 Mar 2019 19:40:42 -0300 | From | Paul Cercueil <> | Subject | Re: [PATCH 1/3] dt-bindings: Add doc for the ingenic-drm driver |
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Hi Sam, thanks for the feedback.
Le ven. 1 mars 2019 à 17:16, Sam Ravnborg <sam@ravnborg.org> a écrit : > Hi Paul. > > Good to see work migrating fbdev => drm. > > Following comments is based on experience while working on migrating > another driver from fbdev => drm. > > On Thu, Feb 28, 2019 at 07:07:54PM -0300, Paul Cercueil wrote: >> Add documentation for the devicetree bindings of the DRM driver for >> the >> JZ47xx family of SoCs from Ingenic. >> >> Signed-off-by: Paul Cercueil <paul@crapouillou.net> >> Tested-by: Artur Rojek <contact@artur-rojek.eu> >> --- >> .../devicetree/bindings/display/ingenic,drm.txt | 30 >> ++++++++++++++++++++++ >> 1 file changed, 30 insertions(+) >> create mode 100644 >> Documentation/devicetree/bindings/display/ingenic,drm.txt >> >> diff --git >> a/Documentation/devicetree/bindings/display/ingenic,drm.txt >> b/Documentation/devicetree/bindings/display/ingenic,drm.txt >> new file mode 100644 >> index 000000000000..52a368ec35cd >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/display/ingenic,drm.txt >> @@ -0,0 +1,30 @@ >> +Ingenic JZ47xx DRM driver >> + >> +Required properties: >> +- compatible: one of: >> + * ingenic,jz4740-drm >> + * ingenic,jz4725b-drm >> +- reg: LCD registers location and length > The fbdev way of doing this was to hardcode register setttings. > In the drm world we read the configuration of the panel and let > this decide the actual configuration. > > Note that no drm drivers supports stn displays and that there > is really no use for this these days. So you can skip the STN parts.
STN panels aren't really my problem; but I have a board with a Sharp LS020B1DD01D panel, which requires the LCD IP to be configured for a "special 2" panel. I also have a board with a "smart" panel (ili9331) that needs a special configuration in the IP. There is nothing in the drm_panel interface that tells me what mode I should use for what panel...
> Also the modern way to specify a panel in the DT is using OF graph > bindings. > You can find many examples how to do this.
Ok, I was looking at the Tegra driver, which uses a "nvidia,panel" DT property. I will change it to use the graph thing.
> I was there with the atmel LCDC driver (not in the kernel yet), > and had some challenges with this. > > Sam
Thanks, -Paul
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