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From: Barry Song <21cnbao@gmail.com>
Date: Tue, 31 Jan 2012 19:04:34 +0800
Message-ID: <CAGsJ_4wyJ6Wymy4AWoW1eHubZX=W7GT_Fbow9ofXoY1RrcHzgA@mail.gmail.com>
Subject: Re: [PATCH 1/3] platform: add common resource requesting and mapping helper
To: Wolfram Sang <w.sang@pengutronix.de>
Cc: Barry Song <Barry.Song@csr.com>, Linus Walleij <linus.walleij@linaro.org>,
        Greg Kroah-Hartman <gregkh@suse.de>, linux-kernel@vger.kernel.org,
        workgroup.linux@csr.com, Erik Gilling <konkers@google.com>,
        Grant Likely <grant.likely@secretlab.ca>,
        linux-mtd@lists.infradead.org, Barry Song <Baohua.Song@csr.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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2012/1/31 Wolfram Sang <w.sang@pengutronix.de>:
> On Tue, Jan 31, 2012 at 06:00:00PM +0800, Barry Song wrote:
>> From: Barry Song <Baohua.Song@csr.com>
>>
>> this patch helps to move the common pattern from
>>
>> "
>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> if (!res) {
>>       ret = -ENODEV;
>>       goto err;
>> }
>
> You don't need to do the error checking for 'res'. You can simply do
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> base = devm_request_and_ioremap(&dev->dev, res);

i do know  devm_request_and_ioremap() does res checking. but that is
implicit, confused and not a smart way actually.
actually, no people by now really use the implicit checking. that
shows people don't really think that is a good programming way.

>
> devm_request_and_ioremap() will check res. Given that, I don't think
> we can save a lot with another wrapper.

i think we can save some.
The story begins from Grant's feedback in:
http://www.spinics.net/lists/arm-kernel/msg157644.html

>
> Thanks,
>
>   Wolfram
>
> --
> Pengutronix e.K.                           | Wolfram Sang                |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |

-barry