clockevents: Provide combined configure and register function

All clockevent devices have the same open coded initialization
functions. Provide an interface which does all necessary
initialization in the core code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/%3C20110518210136.331975870%40linutronix.de%3E

2 files changed, 53 insertions, 0 deletions

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 9466eeb..80acc79e 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -69,6 +69,8 @@ enum clock_event_nofitiers {
  * @retries:		number of forced programming retries
  * @set_mode:		set mode function
  * @broadcast:		function to broadcast events
+ * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
+ * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
  * @name:		ptr to clock event name
  * @rating:		variable to rate clock event devices
  * @irq:		IRQ number (only for non CPU local devices)
@@ -91,6 +93,9 @@ struct clock_event_device {
 	void			(*broadcast)(const struct cpumask *mask);
 	void			(*set_mode)(enum clock_event_mode mode,
 					    struct clock_event_device *);
+	unsigned long		min_delta_ticks;
+	unsigned long		max_delta_ticks;
+
 	const char		*name;
 	int			rating;
 	int			irq;
@@ -123,6 +128,10 @@ extern u64 clockevent_delta2ns(unsigned long latch,
 			       struct clock_event_device *evt);
 extern void clockevents_register_device(struct clock_event_device *dev);
 
+extern void clockevents_config_and_register(struct clock_event_device *dev,
+					    u32 freq, unsigned long min_delta,
+					    unsigned long max_delta);
+
 extern void clockevents_exchange_device(struct clock_event_device *old,
 					struct clock_event_device *new);
 extern void clockevents_set_mode(struct clock_event_device *dev,
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 0d74b9b..c69e88c 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -194,6 +194,50 @@ void clockevents_register_device(struct clock_event_device *dev)
 }
 EXPORT_SYMBOL_GPL(clockevents_register_device);
 
+static void clockevents_config(struct clock_event_device *dev,
+			       u32 freq)
+{
+	unsigned long sec;
+
+	if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
+		return;
+
+	/*
+	 * Calculate the maximum number of seconds we can sleep. Limit
+	 * to 10 minutes for hardware which can program more than
+	 * 32bit ticks so we still get reasonable conversion values.
+	 */
+	sec = dev->max_delta_ticks;
+	do_div(sec, freq);
+	if (!sec)
+		sec = 1;
+	else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
+		sec = 600;
+
+	clockevents_calc_mult_shift(dev, freq, sec);
+	dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
+	dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
+}
+
+/**
+ * clockevents_config_and_register - Configure and register a clock event device
+ * @dev:	device to register
+ * @freq:	The clock frequency
+ * @min_delta:	The minimum clock ticks to program in oneshot mode
+ * @max_delta:	The maximum clock ticks to program in oneshot mode
+ *
+ * min/max_delta can be 0 for devices which do not support oneshot mode.
+ */
+void clockevents_config_and_register(struct clock_event_device *dev,
+				     u32 freq, unsigned long min_delta,
+				     unsigned long max_delta)
+{
+	dev->min_delta_ticks = min_delta;
+	dev->max_delta_ticks = max_delta;
+	clockevents_config(dev, freq);
+	clockevents_register_device(dev);
+}
+
 /*
  * Noop handler when we shut down an event device
  */