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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Thu, 12 Sep 2019 14:03:19 +0200
Message-ID: <CAMuHMdVYqx_znkMbwCVyA6WH8-0uOotL3wXCTkvyXG1=i9W-ng@mail.gmail.com>
Subject: Re: [PATCH] drm: rcar-du: Add r8a77980 support
To:     Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc:     Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVERS FOR RENESAS" <dri-devel@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
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Hi Kieran,

On Thu, Sep 12, 2019 at 12:26 PM Kieran Bingham
<kieran.bingham+renesas@ideasonboard.com> wrote:
> (pulling in +Geert for his opinion on compatible string usages)
>
> On 12/09/2019 11:00, Sergei Shtylyov wrote:> Hello!
> > On 11.09.2019 22:25, Kieran Bingham wrote:
> >> Add direct support for the r8a77980 (V3H).
> >>
> >> The V3H shares a common, compatible configuration with the r8a77970
> >> (V3M) so that device info structure is reused.
> >
> >    Do we really need to add yet another compatible in this case?
> > I just added r8a77970 to the compatible prop in the r8a77980 DT. That's why
> > a patch like this one didn't get posted by me.
>
> It's not just about the compatible string for me here,
>
> There is no indication in the driver that it supports the r8a77980, and
> no comment in the driver to explain that the r8a77980 is shared by the
> r8a77970.
>
> This patch makes that explicit at the driver.
>
> Also - I am considering sending a patch (that I've already created
> anyway) to remove the r8a77970 reference from the
>
>   arch/arm64/boot/dts/renesas/r8a77980.dtsi file.
>
> This is the *only* non r8a77980 reference in this file, so it seems very
> out of place.

Agreed.

> In fact more so than that - except for a seemingly glaring typo, that
> I'll investigate and send a patch for next, this is the *only* cross-soc
> compatible reference:
>
> #!/bin/sh
>
> files=r8a77*.dtsi
>
> for f in $files;
> do
>         soc=`basename $f .dtsi | sed 's/-.*//'`
>         echo "F: $f soc: $soc";
>
>         # Find all references to all socs, then hide 'this' soc
>         grep r8a77 $f | grep -v $soc

This hides the complete line.  So you better use e.g.

    sed -e "s/$soc/soc/ig" $f | grep -i r8a

instead.  No new offenders, though.

> done;

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