Messages in this thread | | | From | Linus Walleij <> | Date | Wed, 29 Apr 2020 14:38:13 +0200 | Subject | Re: [PATCH] gpiolib: add GPIO_SET_DEBOUNCE_IOCTL |
| |
On Wed, Apr 29, 2020 at 2:06 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> I understand the need to set debounce time to make line events > reliable. As I see it: there'll be a couple steps to add this.
I think there is a serious user-facing problem here though, because not all GPIO controllers supports debounce, so the call may return "nope" (error code).
I think that is unavoidable with things like pull-up/down or drive strength, but for debounce I think we could do better. drivers/input/keyboard/gpio_keys.c contains generic debounce code using kernel timers if the GPIO driver cannot provide debouncing, and I have thought for a long time that it would be nice if we could do this generic, so that we always provide debouncing if requested, even for in-kernel consumers but most certainly for userspace consumers, else userspace will just start to reinvent this too.
Yours, Linus Walleij
| |