From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Mike Frysinger" <vapier.adi@gmail.com>
Subject: Re: [PATCH] phylib: make mdio-gpio work without OF (v2)
Date: Tue, 4 Nov 2008 19:09:05 -0500
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To: David Brownell <david-b@pacbell.net>
Cc: Grant Likely <grant.likely@secretlab.ca>, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>, netdev@vger.kernel.org, linux-arm-kernel@lists.arm.linux.org.uk, linux-embedded@vger.kernel.org, Laurent Pinchart <laurentp@cse-semaphore.com>

On Tue, Nov 4, 2008 at 19:04, David Brownell wrote:
> On Tuesday 04 November 2008, Grant Likely wrote:
>> At this point, instead of #ifdeffing the function signature, I would
>> much rather see this generalized as something like
>> 'mdio_gpio_setup()'.  Then move the OF and non-OF specific bits into
>> two new functions; mdio_ofgpio_probe() and mdio_gpio_probe().  The two
>> new functions should be placed with the appropriate bus binding in the
>> #ifdef/#else block at the bottom of the file.
>
> Or if possible something that creates a single #ifdef that
> ensures dead code elimination will remove the "other" branch,
> but ensures all platforms will build both versions:
>
>    #ifdef OF
>    #define using_of    true
>    #else
>    #define using_of    false
>    #endif
>
>    ...
>
>    static int __init mdio_gpio_init(void)
>    {
>        if (using_of)
>                return register mdio_ofgpio driver;
>        else
>                return register mdio_gpio driver;
>    }
>    subsys_initcall(mdio_gpio_init);
>
>    ...
>
> That's generally the preferred way to handle #ifdeffery.
> But I could imagine OF isn't (yet?) set up to handle it.

i agree completely with the inclination to do it all in C as you've
suggested and let the compiler do dead code elimination, but that only
works if the functions in question are defined everywhere (in other
words, there's a linux/ api for it).  i dont think that's the case for
OF (which is what you were implying?) ...
-mike