Re: [PATCH] drivers: gpio: use of_match_ptr() and ACPI_PTR() macros

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Enrico Weigelt, metux IT consult" <info@metux.net>,
	Jonathan Cameron <jic23@kernel.org>
Cc: "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
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Subject: Re: [PATCH] drivers: gpio: use of_match_ptr() and ACPI_PTR() macros
Date: Tue, 17 Nov 2020 18:49:57 +0200	[thread overview]
Message-ID: <CAHp75Vfgs=-_SZoxGf9T93sBdKb6ak_YUi8=WPPF3YeZUsxQcA@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VfPio=TacTTrY=vZp8vZ7qst_7zWeXKDpYvJ6q7oh2Hdw@mail.gmail.com>

On Tue, Nov 17, 2020 at 6:45 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Tue, Nov 17, 2020 at 5:45 PM Enrico Weigelt, metux IT consult
> <info@metux.net> wrote:
> >
> > The of_match_ptr(foo) macro evaluates to foo, only if
> > CONFIG_OF is set, otherwise to NULL. Same does ACPI_PTR with
> > CONFIG_ACPI. That's very helpful for drivers that can be used
> > with or without oftree / acpi.
> >
> > Even though most of the drivers touched here probably don't
> > actually need that, it's also nice for consistency to make it
> > the de-facto standard and change all drivers to use the
> > of_match_ptr() and ACPI_PTR() macros.
> >
> > A nice side effect: in some situations, when compiled w/o
> > CONFIG_OF/CONFIG_ACPI, the corresponding match tables could
> > automatically become unreferenced and optimized-away by the
> > compiler, w/o explicitly cluttering the code w/ ifdef's.
>
> NAK.
>
> It prevents using DT-enabled drivers on ACPI based platforms.
>
> +Cc: Jonathan who had done the opposite in the entire IIO subsystem.

And a side note: use of_match_ptr() and ACPI_PTR() in 99% is a mistake.

-- 
With Best Regards,
Andy Shevchenko