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    SubjectRe: [PATCH RFC] x86: Add user configurable GPIO-lib support

    * Michael Buesch <mb@bu3sch.de> wrote:

    > So this adds user-configurable GPIO support through gpiolib on
    > subarchitectures that do not implement a GPIO implementation, yet.
    > Currently that's everything except X86_RDC321X.
    >
    > The advantage of this is to make it possible to use generic PCI (or
    > other bus) GPIO extention cards in standard PCs through the standard
    > GPIO API.
    >
    > If another subarch implements its own GPIO, it needs to add itself as
    > an inverted dependency to GPIO_USERSELECTION to make sure the user
    > does not enable two GPIO API implementations.
    >
    > About the asm-x86/gpio.h:
    > I'm not sure what this <gpio.h> include currently is.
    > Can somebody explain that to me? Where is this supposed
    > to include a gpio.h file from?
    >
    > What's your opinion on this?

    ( i've Cc:-ed Florian on this who's maintaining the RDC R-321X bits. )

    The longer-term goal is that we'd like to remove the explicit RDC
    sub-arch and just support such systems out of box on x86.

    We are almost there - Florian already moved a few special drivers out of
    arch/x86, the only missing piece is this complication in
    include/asm-x86/timex.h:

    #ifdef CONFIG_X86_ELAN
    # define PIT_TICK_RATE 1189200 /* AMD Elan has different frequency! */
    #elif defined(CONFIG_X86_RDC321X)
    # define PIT_TICK_RATE 1041667 /* Underlying HZ for R8610 */
    #else
    # define PIT_TICK_RATE 1193182 /* Underlying HZ */
    #endif

    ... once that is made dynamic/quirkable we are there.

    And we could even remove the AMD Elan subarch that way: AFAICS it's a
    486 compatible with an A20 quirk and this PIT_TICK quirk.

    ... and if we do that we'll also remove these:

    select GENERIC_GPIO
    select LEDS_CLASS
    select LEDS_GPIO
    select NEW_LEDS

    ... and thus perhaps your GPIO_USERSELECTION patch should move into
    drivers/ and be generally accessible, not special to x86?

    Ingo


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