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 <soren.brinkmann@xilinx.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Link: http://lkml.kernel.org/r/1391466877-28908-3-git-send-email-soren.brinkmann@xilinx.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 6 insertions, 3 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 641d91003a45..f85e5fda9c66 100644
--- a/kernel/time/clockevents.c
+++ b/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;
 }
 
 /**