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Date:   Sat, 18 Apr 2020 00:48:07 +0200
From:   Paul Cercueil <paul@crapouillou.net>
Subject: Re: [RESEND PATCH v5 5/5] input: joystick: Add ADC attached joystick
 driver.
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Artur Rojek <contact@artur-rojek.eu>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Heiko Stuebner <heiko@sntech.de>,
        linux-input <linux-input@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Le sam. 18 avril 2020 =E0 0:49, Andy Shevchenko=20
<andy.shevchenko@gmail.com> a =E9crit :
> On Sat, Apr 18, 2020 at 12:24 AM Paul Cercueil <paul@crapouillou.net>=20
> wrote:
>>  Le sam. 18 avril 2020 =E0 0:10, Andy Shevchenko
>>  <andy.shevchenko@gmail.com> a =E9crit :
>>  > On Fri, Apr 17, 2020 at 11:21 PM Artur Rojek=20
>> <contact@artur-rojek.eu>
>>  > wrote:
>=20
> ...
>=20
>>  >>  +#include <linux/of.h>
>>  >
>>  > Do you really need this? (See below as well)
>=20
>>  >>  +static const struct of_device_id adc_joystick_of_match[] =3D {
>>  >>  +       { .compatible =3D "adc-joystick", },
>>  >>  +       { },
>>  >>  +};
>>  >>  +MODULE_DEVICE_TABLE(of, adc_joystick_of_match);
>>  >>  +
>>  >>  +static struct platform_driver adc_joystick_driver =3D {
>>  >>  +       .driver =3D {
>>  >>  +               .name =3D "adc-joystick",
>>  >
>>  >>  +               .of_match_table =3D
>>  >> of_match_ptr(adc_joystick_of_match),
>>  >
>>  > Drop this a bit harmful of_match_ptr() macro. It should go with=20
>> ugly
>>  > #ifdeffery. Here you simple introduced a compiler warning.
>>=20
>>  I assume you mean #ifdef around the of_device_id + module table=20
>> macro?
>=20
> Yes.
>=20
>>  > On top of that, you are using device property API, OF use in this=20
>> case
>>  > is contradictory (at lest to some extend).
>>=20
>>  I don't see why. The fact that the driver can work when probed from
>>  platform code
>=20
> Ha-ha, tell me how. I would like to be very surprised.

iio_map_array_register(),
pinctrl_register_mappings(),
platform_add_devices(),

you're welcome.

>>  doesn't mean that it shouldn't have a table to probe
>>  from devicetree.
>=20
> I didn't get what you are talking about here. The idea of _unified_
> device property API is to get rid of OF-centric code in favour of more
> generic approach. Mixing those two can be done only in specific cases
> (here is not the one).

And how are we mixing those two here? The only OF-centric thing here is=20
the device table, which is required if we want the driver to probe from=20
devicetree.

-Paul

>=20
> --
> With Best Regards,
> Andy Shevchenko