On Wed, 1 Jul 2015, Thomas Gleixner wrote:

quoted

As I removed this kinetis_pit_enable() line, the timer did not start,
therefore the system became unusable. What could be possible reason for that?

Well, you need to move both, the init and the enable into
set_periodic().

Indeed, something like this worked:

diff --git a/drivers/clocksource/timer-kinetis.c 

b/drivers/clocksource/timer-kinetis.c
index 1424308..41ef94f 100644

--- a/drivers/clocksource/timer-kinetis.c
+++ b/drivers/clocksource/timer-kinetis.c

@@ -61,6 +61,7 @@ struct kinetis_clock_event_ddata {
         struct clock_event_device evtdev;
         void __iomem *base;
         void __iomem *mcr;
+       unsigned long rate;
         spinlock_t lock;
  };

@@ -115,6 +116,7 @@ static int kinetis_clockevent_tmr_set_state_periodic(
         struct kinetis_clock_event_ddata *pit =
                 container_of(evt, struct kinetis_clock_event_ddata, 

evtdev);

+       kinetis_pit_init(pit, (pit->rate / HZ) - 1);
         kinetis_pit_enable(pit, 1);

         return 0;

@@ -235,6 +237,7 @@ static void __init kinetis_clockevent_init(struct 

device_node *np)
                                 kinetis_clockevent_tmr_set_state_oneshot;
                 kinetis_tmr->base = base;
                 kinetis_tmr->mcr = mcr;
+               kinetis_tmr->rate = rate;
                 spin_lock_init(&kinetis_tmr->lock);

                 /*

@@ -250,9 +253,6 @@ static void __init kinetis_clockevent_init(struct 

device_node *np)

                 clockevents_register_device(&kinetis_tmr->evtdev);

-               kinetis_pit_init(kinetis_tmr, (rate / HZ) - 1);
-               kinetis_pit_enable(kinetis_tmr, 1);
-
                 if (request_irq(irq, kinetis_clockevent_tmr_irq_handler,
                                         IRQF_TIMER | IRQF_IRQPOLL,
                                         "kinetis-timer",