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    SubjectRe: [PATCH] gpiolib: add GPIO_SET_DEBOUNCE_IOCTL
    On Mon, May 25, 2020 at 5:17 PM Kent Gibson <warthog618@gmail.com> wrote:

    > > I suppose gpiolib would have to steal or intercept the interrupt
    > > by using e.g. IRQF_SHARED and then just return IRQ_HANDLED
    > > on the first IRQ so the underlying irq handler does not get called.
    >
    > And how would gpiolib ensure that it was first in the chain?

    I don't know.

    > Totally agree with the concept - just trying to work out how to
    > implement it seemlessly given the existing API and usage, and given my
    > limited knowledge of the kernel internals.

    The irqchip maintainers certainly know the answer for the question
    of shared interrupts at least.

    > > Failure is an option! Sorry if I push too complex ideas.
    >
    > I'm not as concerned about complexity as I am about fragility.
    >
    > I don't see any problem adding debounce for gpiolib-cdev.
    > Adding a more complete solution to gpiolib itself is certainly
    > non-trivial, if it is possible at all.

    I agree. It's just that I perceive it as more elegant if we can do that.

    > The path I'll probably be taking is adding a debouncer to gpiolib-cdev,
    > so at least we have a solution for userspace, then take a longer look at
    > the more general solution.

    That's fine! Thanks for looking into this.

    Linus Walleij

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