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    SubjectRe: [PATCH 1/3] platform: add common resource requesting and mapping helper
    hi Wolfram,

    2012/1/31 Wolfram Sang <w.sang@pengutronix.de>:
    > Barry,
    >
    >> > 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.
    >
    > I agree about the implicit thing (keep in mind the function is new). But
    > calling a function "not smart" because it checks its arguments? I do
    > like the NULL check of kfree() for example.

    i didn't mean it is not smart for devm_request_and_ioremap() to check
    its param. that is definitely ok.
    i mean it is not smart for people to depend on another function to do
    implicit check on what they should check by themselves.
    >
    >> actually, no people by now really use the implicit checking. that
    >> shows people don't really think that is a good programming way.
    >
    > I'd think most people just copy&paste and don't have an opinion either
    > way, so the quantity doesn't show much.
    >
    >> > 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
    >
    > I am not sure using 'platform_devm_request_and_ioremap' and later using
    > plain 'devm_*' functions (without platform_-prefix) is less confusing.
    > The alternative would be to check which helper functions also use
    > 'struct resource' and if they do checks on that. If all do that, you
    > would have the simple rule, that you only need to check yourself if you
    > access it yourself.

    it is just a helper, just like clk_disable_unprepare() which do
    clk_disable() + clk_unprepare().

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