Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <c268cb4497cbe79773bb6568f36c37adc6fb5bbe.1665582645.git.geert+renesas@glider.be>
 <Y0cPpJin64ou4ivI@shikoro> <CAMuHMdUqp6J8PZOx57tGpKZKxQBY_bkU7b8Kiqu9DNjmj2vCGg@mail.gmail.com>
 <Y0fFhHYhKC4pbBnh@shikoro>
In-Reply-To: <Y0fFhHYhKC4pbBnh@shikoro>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Thu, 13 Oct 2022 10:24:18 +0200
Message-ID: <CAMuHMdXSxaaajm1SpcgrZo_sk0Ne-Tbx4hTSshNXQUoUCfdYxA@mail.gmail.com>
Subject: Re: [PATCH] dt-bindings: memory: renesas,rpc-if: Document R-Car V4H support
To:     Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Sergei Shtylyov <sergei.shtylyov@gmail.com>,
        linux-renesas-soc@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hai Pham <hai.pham.ud@renesas.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Precedence: bulk

Hi Wolfram,

On Thu, Oct 13, 2022 at 10:00 AM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> > I actually wrote such a patch a while back.
> > However, I didn't send it after discovering the R-Car V3U Series
> > User’s Manual Rev. 0.50 does not mention the fourth Strobe Timing
> > Adjustment bit (STRTIM) in the RPC-IF PHY Control Register (PHYCNT),
> > which is present on R-Car S4-8 and V4H, but not on R-Car Gen3.
>
> I see. Thanks for the heads up! Maybe this is worth a comment because it
> is an exception to the usual behaviour?

You mean an exception to the exception to the usual behaviour that
R-Car <foo>3 is part of the R-Car Gen3 family, making it the normal
rule? ;-)

We're actually not 100% sure the bit is present or not.  Rev. 0.50 is
still an early revision of the R-Car V3U documentation, so it might lack
some updates.  I tried changing all bits of the PHYCNT register, but
unfortunately all bits except for bit 31 stick on all SoCs I tried, so
we can't use this method to determine which bits exist and which don't.

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