clockevents: Adjust timer interval when frequency changes

clockevent devices in periodic mode are not updated when the frequency
of the device changes. Issue a dev->set_mode() callback which forces
the device to reevaluate the timer settings.

Signed-off-by: Soren Brinkmann <[email protected]>
Cc: [email protected]
Cc: Daniel Lezcano <[email protected]>
Cc: Michal Simek <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

Author: sorenb-xlnx

kernel/time/clockevents.c

@@ -443,10 +443,13 @@ int __clockevents_update_freq(struct clock_event_device *dev, u32 freq)
 {
 	clockevents_config(dev, freq);
 
-	if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
-		return 0;
+	if (dev->mode == CLOCK_EVT_MODE_ONESHOT)
+		return clockevents_program_event(dev, dev->next_event, false);
+
+	if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
+		dev->set_mode(CLOCK_EVT_MODE_PERIODIC, dev);
 
-	return clockevents_program_event(dev, dev->next_event, false);
+	return 0;
 }
 
 /**