clockevents: Add helpers to check the state of a clockevent device

Some clockevent drivers, once migrated to use per-state callbacks,
need to check the state of the clockevent device in their callbacks or
interrupt handler.

Add accessor functions clockevent_state_*() to get this information.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/04a717d490335c688dd7af899fbcede97e1bb8ee.1432192527.git.viresh.kumar@linaro.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/clockchips.h

@@ -149,6 +149,32 @@ struct clock_event_device {
 	struct module		*owner;
 } ____cacheline_aligned;
 
+/* Helpers to verify state of a clockevent device */
+static inline bool clockevent_state_detached(struct clock_event_device *dev)
+{
+	return dev->state == CLOCK_EVT_STATE_DETACHED;
+}
+
+static inline bool clockevent_state_shutdown(struct clock_event_device *dev)
+{
+	return dev->state == CLOCK_EVT_STATE_SHUTDOWN;
+}
+
+static inline bool clockevent_state_periodic(struct clock_event_device *dev)
+{
+	return dev->state == CLOCK_EVT_STATE_PERIODIC;
+}
+
+static inline bool clockevent_state_oneshot(struct clock_event_device *dev)
+{
+	return dev->state == CLOCK_EVT_STATE_ONESHOT;
+}
+
+static inline bool clockevent_state_oneshot_stopped(struct clock_event_device *dev)
+{
+	return dev->state == CLOCK_EVT_STATE_ONESHOT_STOPPED;
+}
+
 /*
  * Calculate a multiplication factor for scaled math, which is used to convert
  * nanoseconds based values to clock ticks: