On Mon, Aug 13, 2018 at 8:42 PM Maxime Jourdan <maxi.jourdan@xxxxxxxxxx> wrote: > > 2018-08-13 21:07 GMT+02:00 Rob Herring <robh@xxxxxxxxxx>: > > On Wed, Aug 08, 2018 at 12:00:09AM +0200, Maxime Jourdan wrote: > >> DT bindings doc for amlogic,meson-canvas > >> > >> Signed-off-by: Maxime Jourdan <maxi.jourdan@xxxxxxxxxx> > >> --- > >> .../soc/amlogic/amlogic,meson-canvas.txt | 36 +++++++++++++++++++ > >> 1 file changed, 36 insertions(+) > >> create mode 100644 Documentation/devicetree/bindings/soc/amlogic/amlogic,meson-canvas.txt > >> > >> diff --git a/Documentation/devicetree/bindings/soc/amlogic/amlogic,meson-canvas.txt b/Documentation/devicetree/bindings/soc/amlogic/amlogic,meson-canvas.txt > >> new file mode 100644 > >> index 000000000000..5f0351717bee > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/soc/amlogic/amlogic,meson-canvas.txt > >> @@ -0,0 +1,36 @@ > >> +Amlogic Canvas > >> +================================ > >> + > >> +A canvas is a collection of metadata that describes a pixel buffer. > >> +Those metadata include: width, height, phyaddr, wrapping, block mode > >> +and endianness. > >> + > >> +Many IPs within Amlogic SoCs rely on canvas indexes to read/write pixel data > >> +rather than use the phy addresses directly. For instance, this is the case for > >> +the video decoders and the display. > >> + > >> +Amlogic SoCs have 256 canvas. > >> + > >> +Device Tree Bindings: > >> +--------------------- > >> + > >> +Canvas Provider > >> +-------------------------- > >> + > >> +Required properties: > >> +- compatible: "amlogic,canvas" > >> + > >> +Parent node should have the following properties : > >> +- compatible: "amlogic,gx-dmc-sysctrl", "syscon", "simple-mfd" > > > > Is this documented somewhere? One child function is not a reason for an > > MFD and child nodes. And child nodes like this with no resources are > > unnecessary. > > > > Hi Rob, this was done to follow the same path as other buses on the > platform that have sysctrls in order to provide regmaps to the > devices. > > I can see how it's not really necessary here though, would it be okay > with you if I turned "canvas" into a simple bus subnode, using __iomem > in the device ? That's a driver issue that has little to do with the binding. You can create a regmap for any node, "syscon" just does that automagically for you. Rob
