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. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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