From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh@kernel.org (Rob Herring) Date: Fri, 31 Aug 2018 08:18:36 -0400 Subject: [PATCH 2/3] dt-bindings: firmware: coreboot: document board variant properties In-Reply-To: <20180822120214.11848-2-heiko@sntech.de> References: <20180822120214.11848-1-heiko@sntech.de> <20180822120214.11848-2-heiko@sntech.de> Message-ID: <20180831121836.GA23441@bogus> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > --- > 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