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    SubjectRe: [PATCH RFC] x86: Add user configurable GPIO-lib support
    Date
    Hello Michael, Ingo,

    Le Tuesday 01 July 2008 13:04:37 Ingo Molnar, vous avez écrit :
    > * 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 only reason RDC321x is not yet converted to using gpiolib is the small
    number of actually accessible GPIOs, anyway, I will do the conversion soon.

    > >
    > > 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?
    > >

    This code is inherited from MIPS/ARM before GPIO lib, where generic assembly
    headers provide prototypes for the usual GPIO functions. Boards override
    those functions with their own copy of these GPIO functions.

    > #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.

    Yes, I did not have time to investigate this, and am still wondering if we can
    have dynamic tick rate settings in early board setup code.
    --
    Cordialement, Florian Fainelli
    ------------------------------
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