Re: [PATCH v3 1/2] dt-bindings: media: renesas,vin: Add binding for V4M

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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





[Index of Archives]     [Linux Samsung SOC]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux