Messages in this thread | | | From | Linus Walleij <> | Date | Wed, 27 May 2020 07:31:20 +0200 | Subject | Re: [PATCH] gpiolib: add GPIO_SET_DEBOUNCE_IOCTL |
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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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