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

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Message-ID: <20201117160112.GI1869941@dell>
Date:   Tue, 17 Nov 2020 16:01:12 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Thierry Reding <thierry.reding@...il.com>
Cc:     "Enrico Weigelt, metux IT consult" <info@...ux.net>,
        linux-kernel@...r.kernel.org, linus.walleij@...aro.org,
        bgolaszewski@...libre.com, andrew@...id.au, albeu@...e.fr,
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        Eugeniy.Paltsev@...opsys.com, hoan@...amperecomputing.com,
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Subject: Re: [PATCH] drivers: gpio: use of_match_ptr() and ACPI_PTR() macros

On Tue, 17 Nov 2020, Thierry Reding wrote:

> On Tue, Nov 17, 2020 at 04:43:40PM +0100, Enrico Weigelt, metux IT consult 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.
> 
> Isn't this going to cause a lot of "defined but unused" warnings when
> built without OF support, for example?

Yes, it will.

It also looks like there are some whitespace changes in the patch,
unless of course that's just Git playing tricks!

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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