--- zzzz-none-000/linux-4.9.276/drivers/net/phy/at803x.c	2021-07-20 14:21:16.000000000 +0000
+++ falcon-5530-750/linux-4.9.276/drivers/net/phy/at803x.c	2023-04-05 08:19:01.000000000 +0000
@@ -44,6 +44,7 @@
 #define AT803X_FUNC_DATA			0x4003
 #define AT803X_REG_CHIP_CONFIG			0x1f
 #define AT803X_BT_BX_REG_SEL			0x8000
+#define AT803X_SGMII_ANEG_EN 0x1000
 
 #define AT803X_DEBUG_ADDR			0x1D
 #define AT803X_DEBUG_DATA			0x1E
@@ -277,6 +278,26 @@
 static int at803x_config_init(struct phy_device *phydev)
 {
 	int ret;
+	u32 v;
+
+	if (phydev->drv->phy_id == ATH8031_PHY_ID &&
+	    phydev->interface == PHY_INTERFACE_MODE_SGMII) {
+		v = phy_read(phydev, AT803X_REG_CHIP_CONFIG);
+		/* select SGMII/fiber page */
+		ret = phy_write(phydev, AT803X_REG_CHIP_CONFIG,
+				v & ~AT803X_BT_BX_REG_SEL);
+		if (ret)
+			return ret;
+		/* enable SGMII autonegotiation */
+		ret = phy_write(phydev, MII_BMCR, AT803X_SGMII_ANEG_EN);
+		if (ret)
+			return ret;
+		/* select copper page */
+		ret = phy_write(phydev, AT803X_REG_CHIP_CONFIG,
+				v | AT803X_BT_BX_REG_SEL);
+		if (ret)
+			return ret;
+	}
 
 	ret = genphy_config_init(phydev);
 	if (ret < 0)