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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Tue, 12 Jul 2022 12:11:39 +0200
Message-ID: <CAHp75Vcv3zVGjty_vLUgYu3sowNtg-sWg=qtVt7Vp6mqX6pLvg@mail.gmail.com>
Subject: Re: [PATCH v2 2/3] pinctrl: sunxi: add support for R329 CPUX pin controller
To:     Icenowy Zheng <uwu@icenowy.me>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        Maxime Ripard <mripard@kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        linux-sunxi@lists.linux.dev,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Maxime Ripard <maxime@cerno.tech>
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On Tue, Jul 12, 2022 at 12:10 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Tue, Jul 12, 2022 at 11:37 AM Icenowy Zheng <uwu@icenowy.me> wrote:
> > =E5=9C=A8 2022-07-10=E6=98=9F=E6=9C=9F=E6=97=A5=E7=9A=84 21:06 +0200=EF=
=BC=8CAndy Shevchenko=E5=86=99=E9=81=93=EF=BC=9A
> > > On Sun, Jul 10, 2022 at 10:22 AM Icenowy Zheng <uwu@icenowy.me>
> > > wrote:
>
> ...
>
> > > > +#include <linux/of.h>
> > > > +#include <linux/of_device.h>
> > >
> > > No use of these.
> > >
> > > > +#include <linux/pinctrl/pinctrl.h>
> > >
> > > Missed headers:
> > > mod_devicetable.h
> >
> > Thanks for these.
> >
> > In addition, how to decide what header should be included? The code
> > works properly because of_device.h includes mod_devicetable.h.

Forgot to put in the first place this:

The rule of thumb is Include headers that the header or C module is
direct user of. Additional information is located in the sections
below.

> The best approach is usually learnt with experience =E2=80=94 the more yo=
u
> code, the more you get. One of the rules is to avoid too many
> inclusions and at the same time reduce indirect inclusions, so that
> the headers which are guaranteed to be included by others shouldn't
> appear. Another rule is that, for the headers (*.h files) the forward
> declarations are preferable over the inclusion in case if the opaque
> pointers are in use.

--=20
With Best Regards,
Andy Shevchenko