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    SubjectRe: [PATCH 1/3] gpiolib: Add ability to get GPIO pin direction
    > fails and the pin is not touched.  Seems like adding a well coded
    > chip-specific request() function to drivers where necessary would
    > resolve your concern about reconfiguring pins before checking ownership?

    That seems sensible and it keeps the knowledge out of gpiolib.

    > Also, in most cases I'd think that the BIOS/U-Boot/firmware should have
    > configured the GPIO pins appropriately, which Linux should inherit in
    > general. Linux currently inherits GPIO states that were set in firmware
    > when a GPIO is requested, but it doesn't properly report those values
    > via sysfs - that's the only bug I'm trying to fix.

    Yes - however you can't fix it unless you are prepared to admit that the
    gpio has multiple states. At minimum you need to be able to report


    if you want to generalise it. Otherwise you don't solve the problem
    because you are asking a question that driver cannot answer correctly.

    > Are there many cases where people need to swap a pin from GPIO to alt
    > functionality, and back again in Linux? I have never seen them used
    > like that

    Well I'm not surprised - you can't currently do it that way. The code
    doesn't support it, instead such things are buried in arch code and
    driver specific goo. I question whether it should be buried away like

    That's really about Grant's why do we need it comment rather than about
    your bits. From the point of view of direction reporting (which I'm fully
    in favour of) the only problem that matters is the fact a pin has a
    minimum of four states to report. From that point of view "unavailable"
    is probably a better way to report it than alt_func as it covers all the
    other "unavailable" cases that may exist and haven't yet been thought of.


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