Hi Linus, On Thu, Oct 20, 2016 at 03:56:25PM +0200, Maxime Ripard wrote: > Hi Linus, > > On Thu, Oct 20, 2016 at 03:04:46PM +0200, Linus Walleij wrote: > > On Wed, Oct 19, 2016 at 11:15 AM, Maxime Ripard > > <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > > > > > The pin controller found in the Allwinner SoCs has support for interrupts > > > debouncing. > > > > > > However, this is not done per-pin, preventing us from using the generic > > > pinconf binding for that, > > > > How typical. > > > > > but per irq bank, which, depending on the SoC, > > > ranges from one to five. > > > > > > Introduce a device-wide property to deal with this using a nanosecond > > > resolution. > > > > > > Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> > > (...) > > > +Note: For backward compatibility reasons, the hosc and losc clocks are > > > +only required if you need to use the optional > > > +allwinner,debounce-time-ns property. Any new device tree should set them. > > > + > > > +Optional properties: > > > + - allwinner,debounce-time-ns: Array of debouncing periods in > > > + nanoseconds. One period per irq bank found in the controller > > > > Do you really *need* to specify this with nanosecond resolution? > > > > Else I would suggest to use microsecond resolution and just use > > the generic binding (input-debounce) but on the device node instead > > of the specific handler. > > Theorically, the debouncing clock can be set at 24MHz, which means a > 42ns resolution. > > I've seen that the other bindings usually use microseconds, but in our > case, we can really go lower than that. > > I don't really know if it makes sense though. Any comments on this? Thanks, Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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