On Wed, Aug 22, 2018 at 02:02:13PM +0200, Heiko Stuebner wrote: > Since at least 2014 coreboot exports board specific variant ids for > board-revision, used ram-modules and component variants on the same board > into the loaded devicetree. > > These are set on all devicetree-based Chromebooks since then, so at > least we can make the effort to document these long-used properties. Long used, but never reviewed, so that doesn't really matter. > > A case where these are used is for example to determine the touchscreen > type that is only identifyable via the sku-id when updating its firmware > on the Scarlet tablet from the Gru ChromeOS family. > > Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx> > --- > Documentation/devicetree/bindings/firmware/coreboot.txt | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/firmware/coreboot.txt b/Documentation/devicetree/bindings/firmware/coreboot.txt > index 4c955703cea8..cfc7623e2577 100644 > --- a/Documentation/devicetree/bindings/firmware/coreboot.txt > +++ b/Documentation/devicetree/bindings/firmware/coreboot.txt > @@ -21,6 +21,12 @@ Required properties: > 0xc0389481 that resides in the topmost 8 bytes of the area. > See coreboot's src/include/imd.h for details. > > +Board variant properties determined via strapping measures (like gpios): > + - board-id: board-specific id indicating the board-revision > + - ram-code: board-specific id identifying the used ram-module > + - sku-id: board-specific id indicating a variant (using different > + display panels for example) The appear to be consumed by coreboot, but the purpose of the /firmware nodes has describing firmware interfaces provided by the platform. Not saying we can't put things to configure the firmware there, but it would be a departure and something we should consider. These properties aren't really coreboot specific and probably belong at the root node. Though I think we already discussed a 'board-id' property for QCom (and ended up with a compatible string approach instead. Rob
