On Mon, Nov 07, 2016 at 10:40:04AM +0100, Linus Walleij wrote: > On Wed, Nov 2, 2016 at 8:51 PM, Maxime Ripard > <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Oct 20, 2016 at 03:56:25PM +0200, Maxime Ripard wrote: > >> 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? > > My first thought: can you atleast support both? > > My preference would be to add the standard binding and use that, > and the day you realize that "howli mackarowli, this thingofabob > actually needs to specify with nanosecond precision" then we > could add the nanosecond granularity binding? That works for me. I'll resend the patch. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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