util: Add a function to render timestamp type

TLV_PORT_PROPERTIES_NP carries, among other attributes, a timestamp type
used for that port. In order to make it possible to format the value for
user consumption, introduce a new function ts_str().

Signed-off-by: Petr Machata <petrm@mellanox.com>

util.c

@@ -70,6 +70,24 @@ const char *ev_str[] = {
 	"RS_PASSIVE",
 };
 
+const char *ts_str(enum timestamp_type ts)
+{
+	switch (ts) {
+	case TS_SOFTWARE:
+		return "SOFTWARE";
+	case TS_HARDWARE:
+		return "HARDWARE";
+	case TS_LEGACY_HW:
+		return "LEGACY_HW";
+	case TS_ONESTEP:
+		return "ONESTEP";
+	case TS_P2P1STEP:
+		return "P2P1STEP";
+	}
+
+	return "???";
+}
+
 int addreq(enum transport_type type, struct address *a, struct address *b)
 {
 	void *bufa, *bufb;

util.h

@@ -41,6 +41,13 @@ extern const char *ps_str[];
  */
 extern const char *ev_str[];
 
+/**
+ * Gets a human-readable string for a given timestamp type.
+ * @param ts    Timestamp type.
+ * @return      Human-readable rendering if TS is valid, otherwise "???".
+ */
+const char *ts_str(enum timestamp_type ts);
+
 /**
  * Compares two binary addresses for equality.
  * @param type  One of the enumerated transport types.