net: phy: realtek: add get_rate_matching() for rtl822xb PHYs

Uses vendor register to determine if SerDes is setup in rate-matching mode.

Rate-matching only supported when SerDes is set to 2500base-x.
Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/realtek.c

@@ -726,6 +726,27 @@ static int rtl822xb_config_init(struct phy_device *phydev)
 	return phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x6f11, 0x8020);
 }
 
+static int rtl822xb_get_rate_matching(struct phy_device *phydev,
+				      phy_interface_t iface)
+{
+	int val;
+
+	/* Only rate matching at 2500base-x */
+	if (iface != PHY_INTERFACE_MODE_2500BASEX)
+		return RATE_MATCH_NONE;
+
+	val = phy_read_mmd(phydev, MDIO_MMD_VEND1, RTL822X_VND1_SERDES_OPTION);
+	if (val < 0)
+		return val;
+
+	if ((val & RTL822X_VND1_SERDES_OPTION_MODE_MASK) ==
+	    RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX)
+		return RATE_MATCH_PAUSE;
+
+	/* RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX_SGMII */
+	return RATE_MATCH_NONE;
+}
+
 static int rtl822x_get_features(struct phy_device *phydev)
 {
 	int val;
@@ -1091,6 +1112,7 @@ static struct phy_driver realtek_drvs[] = {
 		.get_features	= rtl822x_get_features,
 		.config_aneg	= rtl822x_config_aneg,
 		.config_init    = rtl822xb_config_init,
+		.get_rate_matching = rtl822xb_get_rate_matching,
 		.read_status	= rtl822xb_read_status,
 		.suspend	= genphy_suspend,
 		.resume		= rtlgen_resume,
@@ -1114,6 +1136,7 @@ static struct phy_driver realtek_drvs[] = {
 		.get_features   = rtl822x_get_features,
 		.config_aneg    = rtl822x_config_aneg,
 		.config_init    = rtl822xb_config_init,
+		.get_rate_matching = rtl822xb_get_rate_matching,
 		.read_status    = rtl822xb_read_status,
 		.suspend        = genphy_suspend,
 		.resume         = rtlgen_resume,
@@ -1125,6 +1148,7 @@ static struct phy_driver realtek_drvs[] = {
 		.get_features   = rtl822x_get_features,
 		.config_aneg    = rtl822x_config_aneg,
 		.config_init    = rtl822xb_config_init,
+		.get_rate_matching = rtl822xb_get_rate_matching,
 		.read_status    = rtl822xb_read_status,
 		.suspend        = genphy_suspend,
 		.resume         = rtlgen_resume,
@@ -1136,6 +1160,7 @@ static struct phy_driver realtek_drvs[] = {
 		.get_features   = rtl822x_get_features,
 		.config_aneg    = rtl822x_config_aneg,
 		.config_init    = rtl822xb_config_init,
+		.get_rate_matching = rtl822xb_get_rate_matching,
 		.read_status    = rtl822xb_read_status,
 		.suspend        = genphy_suspend,
 		.resume         = rtlgen_resume,