Hi Geert and Rob, On Thursday 16 Mar 2017 21:59:04 Geert Uytterhoeven wrote: > On Thu, Mar 16, 2017 at 9:56 PM, Rob Herring <robh@xxxxxxxxxx> wrote: > > On Thu, Mar 16, 2017 at 09:13:16AM +0100, Geert Uytterhoeven wrote: > >> On Wed, Mar 15, 2017 at 6:01 PM, Rob Herring <robh@xxxxxxxxxx> wrote: > >>> On Mon, Mar 06, 2017 at 05:25:56PM +0100, Geert Uytterhoeven wrote: > >>>> Document the optional properties for describing module resets, to > >>>> support resetting display channels and LVDS encoders on R-Car Gen2 and > >>>> Gen3. > >>>> > >>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > >>>> --- > >>>> See "[v2,1/4] dt-bindings: clock: renesas: cpg-mssr: Document reset > >>>> control support" (https://patchwork.kernel.org/patch/9536627/) for the > >>>> format of a reset specifier in the Renesas CPG/MSSR case. > >>>> > >>>> E.g. "resets = <&cpg 310>;" > >>>> > >>>> v2: > >>>> - s/phandles/phandle/. > >>>> > >>>> --- > >>>> > >>>> Documentation/devicetree/bindings/display/renesas,du.txt | 10 ++++++++ > >>>> 1 file changed, 10 insertions(+) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/display/renesas,du.txt > >>>> b/Documentation/devicetree/bindings/display/renesas,du.txt index > >>>> 1a02f099a0ff0a3a..3db418c827193e82 100644 > >>>> --- a/Documentation/devicetree/bindings/display/renesas,du.txt > >>>> +++ b/Documentation/devicetree/bindings/display/renesas,du.txt > >>>> @@ -36,6 +36,16 @@ Required Properties: > >>>> When supplied they must be named "dclkin.x" with "x" being the > >>>> input clock numerical index. > >>>> > >>>> +Optional properties: > >>>> + - resets: A list of phandle + reset-specifier pairs, one for each > >>>> entry in > >>>> + the reset-names property. > >>>> + - reset-names: Names of the resets. This property is > >>>> model-dependent. > >>>> + - R8A779[0123456] use one reset for a group of one or more > >>>> successive > >>>> + channels, and one reset per LVDS encoder (if available). The > >>>> resets > >>>> + must be named "du.x" with "x" being the numerical index of the > >>>> lowest > >>>> + channel in the group. The LVDS resets must be named "lvds.x" > >>>> with "x" > >>>> + being the LVDS encoder numerical index. > >>> > >>> LVDS is not a separate block? > >> > >> Well... from a hardware point of view, the LVDS encoders and DU channels > >> are all separate blocks (they have separate reg blocks, clocks, and > >> resets). But due to the dependencies between the blocks, they're modeled > >> in DT as a single device, with multiple reg, clocks, and resets > >> properties. > > > > Dependencies being DRM requirement of wanting a single device with > > sub-devices or some h/w dependencies? The former shouldn't define your > > binding. > > Hardware dependencies. Laurent can tell you more about them (when he'll > be back). I believe we could model the LVDS encoder as a separate DT node. It was probably a historical mistake (that would however need to be confirmed, I haven't double-checked all details). Obviously I can't break backward compatibility, so we're kind of stuck :-S -- Regards, Laurent Pinchart
