Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220708195510.2951661-1-horatiu.vultur@microchip.com>
 <20220708195510.2951661-2-horatiu.vultur@microchip.com> <CAHp75VdPi8rT_EJd8L8-waAkH_Lm947WVKMLHjjW5MpFW9A06Q@mail.gmail.com>
 <20220711064950.3fqhuat3b23uabkj@soft-dev3-1.localhost>
In-Reply-To: <20220711064950.3fqhuat3b23uabkj@soft-dev3-1.localhost>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 11 Jul 2022 10:31:50 +0200
Message-ID: <CAHp75Vdny6Q3iyO1_Qyz7C+AZ268xRixL6GvCE93f_vfS3bESw@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] pinctrl: ocelot: Fix pincfg for lan966x
To:     Horatiu Vultur <horatiu.vultur@microchip.com>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        kavyasree.kotagiri@microchip.com,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Colin Foster <colin.foster@in-advantage.com>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        Maxime Chevallier <maxime.chevallier@bootlin.com>,
        Michael Walle <michael@walle.cc>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Jul 11, 2022 at 8:45 AM Horatiu Vultur
<horatiu.vultur@microchip.com> wrote:
> The 07/08/2022 23:58, Andy Shevchenko wrote:
> > On Fri, Jul 8, 2022 at 10:10 PM Horatiu Vultur
> > <horatiu.vultur@microchip.com> wrote:

Please, remove unneeded context when replying!

...

> > > +       struct ocelot_match_data *data;
> >
> > Any specific reason why this is not const?
> >
> > > +       data =3D (struct ocelot_match_data *)device_get_match_data(de=
v);
> >
> > And here you drop the qualifier...
> >
> > I would recommend making it const and dropping the cast completely.
>
> If I make this const, but then few lines after I will get the following
> warnings:
>
> drivers/pinctrl/pinctrl-ocelot.c:1983:13: warning: assignment discards =
=E2=80=98const=E2=80=99 qualifier from pointer target type [-Wdiscarded-qua=
lifiers]
> 1983 |  info->desc =3D &data->desc;
>      |             ^
> drivers/pinctrl/pinctrl-ocelot.c:1984:20: warning: assignment discards =
=E2=80=98const=E2=80=99 qualifier from pointer target type [-Wdiscarded-qua=
lifiers]
> 1984 |  info->pincfg_data =3D &data->pincfg_data;
>      |                    ^
>
> Of course I can make also info->desc and info->pincfg_data const but
> then I will get the following warning:
>
> drivers/pinctrl/pinctrl-ocelot.c: In function =E2=80=98ocelot_pinctrl_reg=
ister=E2=80=99:
> drivers/pinctrl/pinctrl-ocelot.c:1723:53: warning: passing argument 2 of =
=E2=80=98devm_pinctrl_register=E2=80=99 discards =E2=80=98const=E2=80=99 qu=
alifier from pointer target type [-Wdiscarded-qualifiers]
> 1723 |  info->pctl =3D devm_pinctrl_register(&pdev->dev, info->desc, info=
);
>      |                                                 ~~~~^~~~~~
> In file included from include/linux/gpio/driver.h:10,
>                  from drivers/pinctrl/pinctrl-ocelot.c:10:
>                       include/linux/pinctrl/pinctrl.h:166:26: note: expec=
ted =E2=80=98struct pinctrl_desc *=E2=80=99 but argument is of type =E2=80=
=98const struct pinctrl_desc *=E2=80=99
> 166 |     struct pinctrl_desc *pctldesc,
>     |     ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
>
> > > +       if (!data)
> > > +               return -EINVAL;

This is not good. Any chances to make it const?

One way is to copy data in a newly allocated buffer (devm_kmemdup() for tha=
t).

--=20
With Best Regards,
Andy Shevchenko