On 05/04/2022 13:47, Biju Das wrote: >> Subject: Re: [PATCH v4 1/5] dt-bindings: arm: renesas: Document Renesas >> RZ/G2UL SMARC EVK >> (...) >>> >>> And what to do when adding more DT overlays for expansion boards? >>> This would become unmanageable soon. >> >> There are two topics here: >> 1. Whether we should follow DT spec. If no, why Renesas is special and for >> other cases we follow DT spec? "Unmanageable" is not the answer here, >> because other platforms will have the same problem. >> >> 2. If the answer for above is yes, we follow DT spec, then the question is >> how to deal with overlays. In current code - I don't know. Long term, >> maybe we need a way to append to existing compatible (to extend it)? >> Some expansion boards do not need to change top level compatible, because >> they only add constrained features (like Arduino shields with some >> regulator). You just add it to DT and presence of new compatible, e.g. of >> regulator, is enough. You do not need to change the top level compatible. >> > > Does the rules for compatible values (most to least descriptive) > also apply to the root node? I don't see any exception in DT spec (page 26), so my answer is yes, the root node has same meaning of "compatible" as other nodes. Best regards, Krzysztof
