On Wed, Nov 11, 2009 at 04:52:06PM +0200, Mika Westerberg wrote:
> On Wed, Nov 11, 2009 at 03:37:38PM +0100, ext Ferenc Wagner wrote:
> > Mika Westerberg <ext-mika.1.westerberg@xxxxxxxxx> writes:
> >
> > > + for (i = 0; i < pdata->nbuttons; i++) {
> > > + struct gpio_keys_button *button = &pdata->buttons[i];
> > > + struct gpio_button_data *bdata = &ddata->data[i];
> > > +
> > > + if (button->code == st->code && button->type == st->type) {
> > > + switch (st->state) {
> > > + case EVENT_STATE_DISABLE:
> > > + if (bdata->state == EVENT_STATE_ENABLE) {
> > > + bdata->state = EVENT_STATE_DISABLE;
> > > + /*
> > > + * Disable physical irq line. This is
> > > + * enough also for keeping device from
> > > + * waking up during sleep so no need
> > > + * to change wakeup flags for this irq.
> > > + */
> > > + disable_irq(gpio_to_irq(button->gpio));
> >
> > Hi Mika,
> >
> > Did you consider what would happen when several GPIO buttons share a
> > single IRQ? The current code does not support this (it uses IRQF_SHARED
> > for a different reason), but this is very much possible: see for example
> > http://thread.gmane.org/gmane.linux.kernel.input/8775 for a related
> > thread which unfortunately died off without conclusion (but the patch
> > went in).
>
> Good point! I didn't consider that at all.
>
> Maybe we disable irq only when it is not shared with anything else (even
> with other GPIO button) and otherwise return -EINVAL or something like
> that?
>
How could a driver know if it is [going to] share irq with another
driver. Dmitry's (the other one ;) ) patch was needed because he wanted
to share IRQ with another device entirely.
--
Dmitry
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