MIME-Version: 1.0
References: <d4a00def-7765-e0e4-c5c7-8d648eeb8cf2@omp.ru> <20211214140607.1147976-1-nikita.yoush@cogentembedded.com>
 <CAMuHMdW=MytCOsghcH9p1GXOPCO3=1mSF8PKj_UAjYEqAq4-1Q@mail.gmail.com> <82b37f1e-a461-8d16-219b-2319e11e1991@cogentembedded.com>
In-Reply-To: <82b37f1e-a461-8d16-219b-2319e11e1991@cogentembedded.com>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Fri, 24 Dec 2021 10:56:48 +0100
Message-ID: <CAMuHMdVhYoFrN59JE3WNmfgiQ59eQBCKiVcHrx7F-zxR=JJ9SQ@mail.gmail.com>
Subject: Re: [PATCH v2] arm64: dts: renesas: r8a77961: Add lvds0 device node
To:     Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Cc:     Magnus Damm <magnus.damm@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Nikita,

On Fri, Dec 24, 2021 at 6:00 AM Nikita Yushchenko
<nikita.yoush@cogentembedded.com> wrote:
> >> +               lvds0: lvds@feb90000 {
> >> +                       compatible = "renesas,r8a7796-lvds";
> >
> > This should be "renesas,r8a77961-lvds".
> > To handle that, both the DT bindings[1] and the driver[2] should
> > be updated.
> >
> > [1] Documentation/devicetree/bindings/display/bridge/renesas,lvds.yaml
> > [2] drivers/gpu/drm/rcar-du/rcar_lvds.c
>
> Ok, will redo that way, although I don't really understand what for to have different compatible strings

Thank you!

> for exactly same IP inside different chips.

Ca. 30% of the "presumed identical" IP blocks in R-Car Gen3 SoCs
turned out not to be that identical...

> Also note that arch/arm64/boot/dts/renesas/r8a77951.dtsi currently has renesas,r8a7795-lvds

That was an early judgment error, which we regret making.
Initially, R-Car H3 ES2.0 (r8a77951) was assumed to be a slightly
improved variant of R-Car H3 ES1.x (r8a77950), while it turned out
to be a completely different SoC.

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