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References: <20240219170337.2161754-1-andriy.shevchenko@linux.intel.com>
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 <CAMuHMdWpepH0P8g9dPfq1rsZRJsvOnoZ7VnjqTL9nkSGtKFpYQ@mail.gmail.com> <Zdy5lDOBrQ9XFCpm@smile.fi.intel.com>
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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Mon, 26 Feb 2024 17:58:29 +0100
Message-ID: <CAMuHMdWoFQfMV90kwy8rxqVt+1eGvh=F7GqtJri5BSydWDiiMQ@mail.gmail.com>
Subject: Re: [PATCH v3 9/9] auxdisplay: Add driver for MAX695x 7-segment LED controllers
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Robin van der Gracht <robin@protonic.nl>, Paul Burton <paulburton@kernel.org>
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Hi Andy,

On Mon, Feb 26, 2024 at 5:17=E2=80=AFPM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> On Mon, Feb 26, 2024 at 05:01:46PM +0100, Geert Uytterhoeven wrote:
> > On Mon, Feb 19, 2024 at 6:03=E2=80=AFPM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > > Add initial driver for the MAX6958 and MAX6959 7-segment LED
> > > controllers.
>
> > LGTM, so
> > Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> Thanks, but see below.
>
> ...
>
> > > +       u8 buf[4];
> > > +
> > > +       /* Map segments according to datasheet */
> > > +       buf[0] =3D bitrev8(map_to_seg7(&map->map.seg7, *s++)) >> 1;
> > > +       buf[1] =3D bitrev8(map_to_seg7(&map->map.seg7, *s++)) >> 1;
> > > +       buf[2] =3D bitrev8(map_to_seg7(&map->map.seg7, *s++)) >> 1;
> > > +       buf[3] =3D bitrev8(map_to_seg7(&map->map.seg7, *s++)) >> 1;
> >
> > for (unsigned int i =3D 0; i < linedisp->num_chars; i++) { ... }
> >
> > > +
> > > +       regmap_bulk_write(priv->regmap, REG_DIGIT(0), buf, ARRAY_SIZE=
(buf));
> >
> > linedisp->num_chars
>
> Maybe, but then we probably want to synchronize the 4 there and here as w=
e
> can't have VLA on stack.

You can still keep the maximum buf[4], so no VLA needed?

>
> > > +}
>
> ...
>
> > > +       ret =3D linedisp_register(&priv->linedisp, dev, 4, &max6959_l=
inedisp_ops);
> >
> > + device_property_read_u32(dev, "display-width-chars", ...) handling.
>
> Not sure it should be part of this series.

Fair enough, so please go ahead without.

Even "display-width-chars" might not cover all cases, as a board
may use any subset of the 4 DIGn signals, even in any order...

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds