Hi Niklas, On Thu, Jun 20, 2024 at 7:22 PM Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> wrote: > On 2024-06-20 17:27:00 +0100, Conor Dooley wrote: > > > + - items: > > > + - enum: > > > - renesas,vin-r8a779g0 # R-Car V4H > > > + - renesas,vin-r8a779h0 # R-Car V4M > > > + - const: renesas,rcar-gen4-vin # Generic R-Car Gen4 > > > > > > If so I can see that working as I could still fix any issues that come > > > from differences between V4H and V4M if needed. If so do you think it > > > best to add this in two different patches? One to add the > > > renesas,rcar-gen4-vin fallback (which will also need DTS updates to fix > > > warnings from exciting users of V4H not listing the gen4 fallback) and > > > one to add V4M? > > > > > > I would just do: > > diff --git a/Documentation/devicetree/bindings/media/renesas,vin.yaml b/Documentation/devicetree/bindings/media/renesas,vin.yaml > > index 5539d0f8e74d..22bbad42fc03 100644 > > --- a/Documentation/devicetree/bindings/media/renesas,vin.yaml > > +++ b/Documentation/devicetree/bindings/media/renesas,vin.yaml > > @@ -54,6 +54,9 @@ properties: > > - renesas,vin-r8a77995 # R-Car D3 > > - renesas,vin-r8a779a0 # R-Car V3U > > - renesas,vin-r8a779g0 # R-Car V4H > > + - items: > > + - const: renesas,vin-r8a779h0 # R-Car V4L2 > > + - const: renesas,vin-r8a779g0 # R-Car V4H > > @Geert: What do you think about this? This would be a first use-case for > compatibles crossing SoC DTS files that I know of. I'm a bit uneasy > going down this road. Me too ;-) > Would this not also effect the existing users of renesas,vin-r8a779g0 > which would now need something similar to what you propose below with a > list of SoC compatibles and a fallback. > > > > > reg: > > maxItems: 1 > > > > Which requires no driver or dts changes. That could become: > > - items: > > - enum: > > - renesas,vin-r8a779h0 # R-Car V4L2 > > - renesas,vin-r8a779i0 # R-Car R4P17 > > - const: renesas,vin-r8a779g0 # R-Car V4H > > FWIW, on Gen2 where fallback es where useful compared to Gen3 we did > this with "renesas,rcar-gen2-vin". We do know there are differences (albeit probably small) among the R-Car Gen4 VIN implementations, so I am reluctant to add a family-specific compatible value. Typically we only use a family-specific compatible value if the IP cores are known (or better, assumed ;-) to be identical. And sometimes our assumptions turn out to be wrong... See slides 25-33 (last two for the numbers) of my talk at ER2019 https://embedded-recipes.org/2019/talks/herd-your-socs-become-a-matchmaker/ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
