Re: [PATCH v4 1/5] dt-bindings: media: renesas,vin: Add Gen4 family fallback

["Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>]

Hi Geert,

Thanks for your review.

On 2024-07-02 09:52:08 +0200, Geert Uytterhoeven wrote:
> Hi Niklas,
> 
> On Mon, Jun 24, 2024 at 4:43 PM Niklas Söderlund
> <niklas.soderlund+renesas@ragnatech.se> wrote:
> > The two Gen4 SoCs released (V4H and V4M) that have a video capture
> > pipeline the VIN IP are very similar.
> >
> > The datasheet for the two SoCs have small nuances around the Pre-Clip
> > registers ELPrC and EPPrC in three use-cases, interlaced images,
> > embedded data and RAW8 input. On V4H the values written to the registers
> > are based on odd numbers while on V4M they are even numbers, values are
> > based on the input image size. No board that uses these SoCs which also
> > have the external peripherals to test these nuances exists. Most likely
> > this is an issue in the datasheet.
> >
> > Before adding bindings for V4M add a family compatible fallback for
> > Gen4. That way the driver only needs to be updated once for Gen4, and we
> > still have the option to fix any problems in the driver if any testable
> > differences between the two SoCs is found.
> >
> > There are already DTS files using the renesas,vin-r8a779g0 compatible
> > which needs to be updated to not produce a warning for DTS checks. And
> > the driver will need to kept compatible with renesas,vin-r8a779g0, but
> > for new Gen4 SoCs such as V4M we can avoid this.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > ---
> > * Changes since v3
> > - New in v4.
> 
> Thanks for your patch!
> 
> > --- a/Documentation/devicetree/bindings/media/renesas,vin.yaml
> > +++ b/Documentation/devicetree/bindings/media/renesas,vin.yaml
> > @@ -53,7 +53,10 @@ properties:
> >                - renesas,vin-r8a77990 # R-Car E3
> >                - renesas,vin-r8a77995 # R-Car D3
> >                - renesas,vin-r8a779a0 # R-Car V3U
> 
> I think R-Car V3U should be moved below, too, as it's the first
> member of the R-Car Gen4 family, despite the name.

I was a bit conflicted about if I should do this and opted to for the 
least intrusive change. But the change seems to have landed on a good 
note, I will do a new version that covers V3U as well.

> 
> > +      - items:
> > +          - enum:
> >                - renesas,vin-r8a779g0 # R-Car V4H
> > +          - const: renesas,rcar-gen4-vin # Generic R-Car Gen4
> 
> If all differences in the pipeline can be devised from the topology
> in DT:

It can.

> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Thanks!

> 
> >
> >    reg:
> >      maxItems: 1
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> -- 
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> 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

-- 
Kind Regards,
Niklas Söderlund