Provide a method to report the sync interval to the clock.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

clock.c

@@ -601,6 +601,16 @@ enum servo_state clock_synchronize(struct clock *c,
 	return state;
 }
 
+void clock_sync_interval(struct clock *c, int n)
+{
+	int shift = c->dds.freq_est_interval - n;
+
+	if (shift < 0)
+		shift = 0;
+
+	c->fest.max_count = (1 << shift);
+}
+
 struct timePropertiesDS *clock_time_properties(struct clock *c)
 {
 	return &c->tds;

clock.h

@@ -184,6 +184,13 @@ enum servo_state clock_synchronize(struct clock *c,
 				   Integer64 correction1,
 				   Integer64 correction2);
 
+/**
+ * Inform a slaved clock about the master's sync interval.
+ * @param c  The clock instance.
+ * @param n  The logarithm base two of the sync interval.
+ */
+void clock_sync_interval(struct clock *c, int n);
+
 /**
  * Obtain a clock's time properties data set.
  * @param c  The clock instance.