net: phy: tja11xx: add SQI support

This patch implements reading of the Signal Quality Index for better
cable/link troubleshooting.
Signed-off-by: NOleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/nxp-tja11xx.c

@@ -53,6 +53,8 @@
 
 #define MII_COMMSTAT			23
 #define MII_COMMSTAT_LINK_UP		BIT(15)
+#define MII_COMMSTAT_SQI_STATE		GENMASK(7, 5)
+#define MII_COMMSTAT_SQI_MAX		7
 
 #define MII_GENSTAT			24
 #define MII_GENSTAT_PLL_LOCKED		BIT(14)
@@ -329,6 +331,22 @@ static int tja11xx_read_status(struct phy_device *phydev)
 	return 0;
 }
 
+static int tja11xx_get_sqi(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = phy_read(phydev, MII_COMMSTAT);
+	if (ret < 0)
+		return ret;
+
+	return FIELD_GET(MII_COMMSTAT_SQI_STATE, ret);
+}
+
+static int tja11xx_get_sqi_max(struct phy_device *phydev)
+{
+	return MII_COMMSTAT_SQI_MAX;
+}
+
 static int tja11xx_get_sset_count(struct phy_device *phydev)
 {
 	return ARRAY_SIZE(tja11xx_hw_stats);
@@ -683,6 +701,8 @@ static struct phy_driver tja11xx_driver[] = {
 		.config_aneg	= tja11xx_config_aneg,
 		.config_init	= tja11xx_config_init,
 		.read_status	= tja11xx_read_status,
+		.get_sqi	= tja11xx_get_sqi,
+		.get_sqi_max	= tja11xx_get_sqi_max,
 		.suspend	= genphy_suspend,
 		.resume		= genphy_resume,
 		.set_loopback   = genphy_loopback,
@@ -699,6 +719,8 @@ static struct phy_driver tja11xx_driver[] = {
 		.config_aneg	= tja11xx_config_aneg,
 		.config_init	= tja11xx_config_init,
 		.read_status	= tja11xx_read_status,
+		.get_sqi	= tja11xx_get_sqi,
+		.get_sqi_max	= tja11xx_get_sqi_max,
 		.suspend	= genphy_suspend,
 		.resume		= genphy_resume,
 		.set_loopback   = genphy_loopback,
@@ -715,6 +737,8 @@ static struct phy_driver tja11xx_driver[] = {
 		.config_aneg	= tja11xx_config_aneg,
 		.config_init	= tja11xx_config_init,
 		.read_status	= tja11xx_read_status,
+		.get_sqi	= tja11xx_get_sqi,
+		.get_sqi_max	= tja11xx_get_sqi_max,
 		.match_phy_device = tja1102_p0_match_phy_device,
 		.suspend	= genphy_suspend,
 		.resume		= genphy_resume,
@@ -736,6 +760,8 @@ static struct phy_driver tja11xx_driver[] = {
 		.config_aneg	= tja11xx_config_aneg,
 		.config_init	= tja11xx_config_init,
 		.read_status	= tja11xx_read_status,
+		.get_sqi	= tja11xx_get_sqi,
+		.get_sqi_max	= tja11xx_get_sqi_max,
 		.match_phy_device = tja1102_p1_match_phy_device,
 		.suspend	= genphy_suspend,
 		.resume		= genphy_resume,