Re: [PATCH] spi: sh-msiof: Enforce fixed DTDL for R-Car H3

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: linux-spi@vger.kernel.org, linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH] spi: sh-msiof: Enforce fixed DTDL for R-Car H3
Date: Thu, 26 Jan 2023 14:43:32 +0100	[thread overview]
Message-ID: <CAMuHMdUBr+3EeErmmH_Qk+sPZfZdNsX88BK=v15wbBwsL5m7fQ@mail.gmail.com> (raw)
In-Reply-To: <Y9KC4Pu/AnnXOLhI@ninjato>

Hi Wolfram,

On Thu, Jan 26, 2023 at 2:40 PM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> > > I have to disagree here. The docs say that other values are prohibited.
> > > IMO the driver should take care of valid values then. We should not rely
> > > on user provided input.
> >
> > Then we should make sure the user cannot override to an invalid value
> > through "renesas,dtdl" either?
>
> We do. The new flag is checked after sh_msiof_spi_parse_dt(), so any
> user input will be overwritten with the only value allowed.

OK>

> > To be clarified with Renesas?
>
> Frankly, I don't think it is worth the hazzle and just stick to the
> latest docs. Yes, they may be inaccurate for ES2.0 but what is the
> downside? Will it break things or is this just a little overhead?

I don't know.
You have to try it with a real SPI device, and/or look at the SPI bus
signals with a logic analyzer.

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