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.
> So maybe we need to factor out the body
> and do:
>
> if (!ts->gpio_int)
> zforce_report_data(...)
> else
> while (gpiod_get_value_cansleep(ts->gpio_int))
> zforce_report_data(...);
>
> Or we could install 2 different interrupt handlers, depending on the
> presence of interrupt gpio.
Heiko
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