Introduce the gmCapable flag for use with 802.1AS clocks.

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

clock.c

@@ -76,6 +76,7 @@ struct clock {
 	int nports; /* does not include the UDS port */
 	int free_running;
 	int freq_est_interval;
+	int grand_master_capable; /* for 802.1AS only */
 	int utc_timescale;
 	int leap_set;
 	int kernel_leap;
@@ -587,6 +588,7 @@ struct clock *clock_create(int phc_index, struct interface *iface, int count,
 
 	c->free_running = dds->free_running;
 	c->freq_est_interval = dds->freq_est_interval;
+	c->grand_master_capable = dds->grand_master_capable;
 	c->kernel_leap = dds->kernel_leap;
 	c->utc_offset = CURRENT_UTC_OFFSET;
 	c->time_source = dds->time_source;
@@ -745,6 +747,11 @@ void clock_follow_up_info(struct clock *c, struct follow_up_info_tlv *f)
 	       sizeof(c->status.lastGmPhaseChange));
 }
 
+int clock_gm_capable(struct clock *c)
+{
+	return c->grand_master_capable;
+}
+
 struct ClockIdentity clock_identity(struct clock *c)
 {
 	return c->dds.clockIdentity;

clock.h

@@ -100,6 +100,14 @@ UInteger8 clock_domain_number(struct clock *c);
  */
 void clock_follow_up_info(struct clock *c, struct follow_up_info_tlv *f);
 
+/**
+ * Obtain the gmCapable flag from a clock's default data set.
+ * This function is specific to the 802.1AS standard.
+ * @param c  The clock instance.
+ * @return One if the clock is capable of becoming grand master, zero otherwise.
+ */
+int clock_gm_capable(struct clock *c);
+
 /**
  * Obtain a clock's identity from its default data set.
  * @param c  The clock instance.

ds.h

@@ -53,6 +53,7 @@ struct default_ds {
 	struct defaultDS dds;
 	int free_running;
 	int freq_est_interval; /*log seconds*/
+	int grand_master_capable; /*802.1AS only*/
 	int stats_interval; /*log seconds*/
 	int kernel_leap;
 	int sanity_freq_limit;

ptp4l.c

@@ -53,6 +53,7 @@ static struct config cfg_settings = {
 		},
 		.free_running = 0,
 		.freq_est_interval = 1,
+		.grand_master_capable = 1,
 		.stats_interval = 0,
 		.kernel_leap = 1,
 		.sanity_freq_limit = 200000000,