ethtool: add a new command for getting PHC virtual clocks

Add an interface for getting PHC (PTP Hardware Clock)
virtual clocks, which are based on PHC physical clock
providing hardware timestamp to network packets.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index f9dcbad..798231b 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -4,6 +4,7 @@
 #include <linux/net_tstamp.h>
 #include <linux/phy.h>
 #include <linux/rtnetlink.h>
+#include <linux/ptp_clock_kernel.h>
 
 #include "common.h"
 
@@ -554,6 +555,18 @@ int __ethtool_get_ts_info(struct net_device *dev, struct ethtool_ts_info *info)
 	return 0;
 }
 
+int ethtool_get_phc_vclocks(struct net_device *dev, int **vclock_index)
+{
+	struct ethtool_ts_info info = { };
+	int num = 0;
+
+	if (!__ethtool_get_ts_info(dev, &info))
+		num = ptp_get_vclocks_index(info.phc_index, vclock_index);
+
+	return num;
+}
+EXPORT_SYMBOL(ethtool_get_phc_vclocks);
+
 const struct ethtool_phy_ops *ethtool_phy_ops;
 
 void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops)