On Wed, Jul 29, 2015 at 08:17:10PM +0200, Heiko Stübner wrote:
> Hi Dmitry,
>
> Am Mittwoch, 29. Juli 2015, 10:53:04 schrieb Dmitry Torokhov:
> > On Tue, Jul 28, 2015 at 11:43:20PM +0200, Heiko Stübner wrote:
>
> [snip]
>
> > > > > @@ -510,7 +511,18 @@ static irqreturn_t zforce_irq_thread(int irq,
> > > > > void
> > > > > *dev_id)>
> > > > >
> > > > > if (!ts->suspending && device_may_wakeup(&client->dev))
> > > > >
> > > > > pm_stay_awake(&client->dev);
> > > > >
> > > > > - while (gpiod_get_value_cansleep(ts->gpio_int)) {
> > > > > + while (run) {
> > > > > + /*
> > > > > + * Exit the loop if either
> > > > > + * - the optional interrupt GPIO isn't specified
> > > > > + * (there is only one packet read per ISR invocation,
> then)
> > > > > + * or
> > > > > + * - the GPIO isn't active any more
> > > > > + * (packet read until the level GPIO indicates that there
> is
> > > > > + * no IRQ any more)
> > > > > + */
> > > > > + run = gpiod_get_value_cansleep(ts->gpio_int);
> > > > > +
> > >
> > > alteratively you could simply convert to a
> > >
> > > /* Run at least once, or as long as the interrupt gpio is active. */
> > > do {
> > >
> > > ...
> > >
> > > } while(gpiod_get_value_cansleep(ts->gpio_int));
> > >
> > > saving the additional variable run and a lot of lines, while still running
> > > at least once.
> >
> > But I think that means that we'll try to read even if gpio is not active
> > anymore on the first iteration.
>
> I don't think this is a possible scenario :-)
>
> The interrupt is only used for transmission of touch-data and is pulled low as
> long as the host hasn't fetched all touch-packages. So if nothing else except
> the zforce-driver talks to the chip, the gpio will stay on.
>
> And when we're entering the interrupt handler, there is at least one touch-
> data package waiting.
I see. Then please ignore me ;)
--
Dmitry
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