Input: wm97xx-core - only schedule interrupt handler if not already scheduled

As well as clarifying the fact that the driver can cope if a second
interrupt occurs before the IRQ work is scheduled this also ensures
that calls to the machine irq_enable() are balanced, making that easier
to implement.  Normally this is redundant due to the interrupt disabling
but some unusal board configurations can trigger it.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
index 2910999e05a068ee6dfb8615a5fa92c0b401d405..e27b1e060b33c4e39ff04298011d1b487a65e0d0 100644 (file)
--- a/drivers/input/touchscreen/wm97xx-core.c
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -328,18 +328,18 @@ static void wm97xx_pen_irq_worker(struct work_struct *work)
  *
  * We have to disable the codec interrupt in the handler because it
  * can take upto 1ms to clear the interrupt source. We schedule a task
- * in a work queue to do the actual interaction with the chip (it
- * doesn't matter if we end up reenqueing it before it is executed
- * since we don't touch the chip until it has run).  The interrupt is
- * then enabled again in the slow handler when the source has been
- * cleared.
+ * in a work queue to do the actual interaction with the chip.  The
+ * interrupt is then enabled again in the slow handler when the source
+ * has been cleared.
  */
 static irqreturn_t wm97xx_pen_interrupt(int irq, void *dev_id)
 {
        struct wm97xx *wm = dev_id;
 
-       wm->mach_ops->irq_enable(wm, 0);
-       queue_work(wm->ts_workq, &wm->pen_event_work);
+       if (!work_pending(&wm->pen_event_work)) {
+               wm->mach_ops->irq_enable(wm, 0);
+               queue_work(wm->ts_workq, &wm->pen_event_work);
+       }
 
        return IRQ_HANDLED;
 }