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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Mon, 5 Feb 2024 20:01:17 +0100
Message-ID: <CAMuHMdUQLWBQemtgnCHj64wCYAET8J2-MgbisyMChSbh0k0L7w@mail.gmail.com>
Subject: Re: [PATCH] pmdomain: mediatek: Use devm_platform_get_and_ioremap_resource()
 in init_scp()
To: Markus Elfring <Markus.Elfring@web.de>
Cc: linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, 
	linux-pm@vger.kernel.org, kernel-janitors@vger.kernel.org, 
	Angelo Gioacchino Del Regno <angelogioacchino.delregno@collabora.com>, 
	=?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>, 
	Jernej Skrabec <jernej.skrabec@gmail.com>, Matthias Brugger <matthias.bgg@gmail.com>, 
	Rob Herring <robh@kernel.org>, Ulf Hansson <ulf.hansson@linaro.org>, 
	LKML <linux-kernel@vger.kernel.org>
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Hi Markus,

On Mon, Feb 5, 2024 at 6:28=E2=80=AFPM Markus Elfring <Markus.Elfring@web.d=
e> wrote:
> >> +++ b/drivers/pmdomain/mediatek/mtk-scpsys.c
> >> @@ -441,8 +441,7 @@ static struct scp *init_scp(struct platform_device=
 *pdev,
> >>
> >>         scp->dev =3D &pdev->dev;
> >>
> >> -       res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> -       scp->base =3D devm_ioremap_resource(&pdev->dev, res);
> >> +       scp->base =3D devm_platform_get_and_ioremap_resource(pdev, 0, =
&res);
> >
> > Given res is further unused, please use devm_platform_ioremap_resource(=
)
> > instead, and remove the local variable res.
>
> I got another idea after looking at the implementation of the function
> =E2=80=9Cdevm_platform_get_and_ioremap_resource=E2=80=9D once more.
> https://elixir.bootlin.com/linux/v6.8-rc3/source/drivers/base/platform.c#=
L87
>
> It seems that it is supported to pass a null pointer for the last paramet=
er
> (while this possibility is not mentioned in the interface description so =
far).
> How do you think about to benefit from such a design option any more
> (instead of the determination of a corresponding platform device)?

Yes, you can pass a NULL pointer as the last parameter.
And as this is very common, the wrapper devm_platform_ioremap_resource()
exists.

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