net: phy: restart phy autonegotiation after EEE advertisment change

When the EEE advertisment is changed, we should restart autonegotiation
to update the link partner with the new EEE settings.  Add this trigger
but only if the advertisment has changed.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy.c

@@ -1332,7 +1332,7 @@ EXPORT_SYMBOL(phy_ethtool_get_eee);
  */
 int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data)
 {
-	int cap, adv;
+	int cap, old_adv, adv, ret;
 
 	if (!phydev->drv)
 		return -EIO;
@@ -1342,12 +1342,29 @@ int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data)
 	if (cap < 0)
 		return cap;
 
+	old_adv = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_AN_EEE_ADV);
+	if (old_adv < 0)
+		return old_adv;
+
 	adv = ethtool_adv_to_mmd_eee_adv_t(data->advertised) & cap;
 
 	/* Mask prohibited EEE modes */
 	adv &= ~phydev->eee_broken_modes;
 
-	return phy_write_mmd(phydev, MDIO_MMD_AN, MDIO_AN_EEE_ADV, adv);
+	if (old_adv != adv) {
+		ret = phy_write_mmd(phydev, MDIO_MMD_AN, MDIO_AN_EEE_ADV, adv);
+		if (ret < 0)
+			return ret;
+
+		/* Restart autonegotiation so the new modes get sent to the
+		 * link partner.
+		 */
+		ret = genphy_restart_aneg(phydev);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
 }
 EXPORT_SYMBOL(phy_ethtool_set_eee);