linux-kernel - Re: [PATCH] drivers: gpio: use of_match_ptr() and ACPI

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Message-ID: <CAHp75Vfgs=-_SZoxGf9T93sBdKb6ak_YUi8=WPPF3YeZUsxQcA@mail.gmail.com>
Date:   Tue, 17 Nov 2020 18:49:57 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     "Enrico Weigelt, metux IT consult" <info@...ux.net>,
        Jonathan Cameron <jic23@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Andrew Jeffery <andrew@...id.au>, Alban Bedel <albeu@...e.fr>,
        Florian Fainelli <f.fainelli@...il.com>,
        Scott Branden <sbranden@...adcom.com>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>,
        Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>,
        Hoan Tran <hoan@...amperecomputing.com>,
        Serge Semin <fancer.lancer@...il.com>, orsonzhai@...il.com,
        baolin.wang7@...il.com, zhang.lyra@...il.com,
        Vladimir Zapolskiy <vz@...ia.com>,
        Marek Behún <marek.behun@....cz>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, Lee Jones <lee.jones@...aro.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Sascha Hauer <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        linux-pwm@...r.kernel.org,
        Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
        linux-tegra@...r.kernel.org
Subject: Re: [PATCH] drivers: gpio: use of_match_ptr() and ACPI_PTR() macros

On Tue, Nov 17, 2020 at 6:45 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Tue, Nov 17, 2020 at 5:45 PM Enrico Weigelt, metux IT consult
> <info@...ux.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