On Thu, Nov 13, 2014 at 12:14 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > Hi, > > On 11/13/2014 12:02 PM, Grant Likely wrote: >> On Thu, Nov 13, 2014 at 8:50 AM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: >>> Since simplefb nodes do not relate directly to hw typically they have been >>> placed in the root of the devicetree. As the represent runtime information >>> having them as sub-nodes of /chosen is more logical, specify this. >>> >>> Also specify when to set the chosen stdout-path property to a simplefb node. >>> >>> For reliable handover to a hardware specific driver, that driver needs to >>> know which simplefb to unregister when taking over, specify how the hw driver >>> can find the matching simplefb node. >>> >>> Last add some advice on how to fill and use simplefb nodes from a firmware >>> pov. >>> >>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> >>> Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> >>> -- >>> Changes in v2: >>> -Add stdout-path to the example code >>> --- >>> .../bindings/video/simple-framebuffer.txt | 38 +++++++++++++++++++++- >>> 1 file changed, 37 insertions(+), 1 deletion(-) >>> >>> diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> index 8f35718..8b7ecf6 100644 >>> --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> @@ -4,6 +4,26 @@ A simple frame-buffer describes a frame-buffer setup by firmware or >>> the bootloader, with the assumption that the display hardware has already >>> been set up to scan out from the memory pointed to by the reg property. >>> >>> +Since simplefb nodes represent runtime information they must be sub-nodes of >>> +the chosen node (*). The primary display node must be named framebuffer0, >>> +additional nodes must be called framebuffer1, etc. >> >> Thinking more about our conversation yesterday, the preferred name >> should still be framebuffer@<address>. There is no reason to break >> with established convention, and as mentioned in my reply on patch #2, >> using the name is not the preferred way to identify a device node. So, >> my recommendation is to prefer the name "framebuffer@<addr>", but if >> it is inconvenient because the address isn't known, then >> "framebuffer#" is acceptable. > > Since we want to use pre-filled simplefb nodes already present in the devicetree, > and u-boot is the one chosing the framebuffer address we don't know the > address to put in the dts file beforehand, so framebuffer# it is. fdt_set_name() is available to U-Boot to rename a node. :-) Prepopulating with /chosen/framebuffer#, and then renaming to /chosen/framebuffer@<addr> is perfectly reasonable. g. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
