diff --git a/drivers/net/dsa/mt7530-mdio.c b/drivers/net/dsa/mt7530-mdio.c
index 088533663b83..fa3ee85a99c1 100644
--- a/drivers/net/dsa/mt7530-mdio.c
+++ b/drivers/net/dsa/mt7530-mdio.c
@@ -81,17 +81,14 @@ static const struct regmap_bus mt7530_regmap_bus = {
 };
 
 static int
-mt7531_create_sgmii(struct mt7530_priv *priv, bool dual_sgmii)
+mt7531_create_sgmii(struct mt7530_priv *priv)
 {
 	struct regmap_config *mt7531_pcs_config[2] = {};
 	struct phylink_pcs *pcs;
 	struct regmap *regmap;
 	int i, ret = 0;
 
-	/* MT7531AE has two SGMII units for port 5 and port 6
-	 * MT7531BE has only one SGMII unit for port 6
-	 */
-	for (i = dual_sgmii ? 0 : 1; i < 2; i++) {
+	for (i = priv->p5_sgmii ? 0 : 1; i < 2; i++) {
 		mt7531_pcs_config[i] = devm_kzalloc(priv->dev,
 						    sizeof(struct regmap_config),
 						    GFP_KERNEL);
diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 436d5c311be0..ab9b291c7a5f 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -487,15 +487,6 @@ mt7530_pad_clk_setup(struct dsa_switch *ds, phy_interface_t interface)
 	return 0;
 }
 
-static bool mt7531_dual_sgmii_supported(struct mt7530_priv *priv)
-{
-	u32 val;
-
-	val = mt7530_read(priv, MT7531_TOP_SIG_SR);
-
-	return (val & PAD_DUAL_SGMII_EN) != 0;
-}
-
 static int
 mt7531_pad_setup(struct dsa_switch *ds, phy_interface_t interface)
 {
@@ -510,9 +501,6 @@ mt7531_pll_setup(struct mt7530_priv *priv)
 	u32 xtal;
 	u32 val;
 
-	if (mt7531_dual_sgmii_supported(priv))
-		return;
-
 	val = mt7530_read(priv, MT7531_CREV);
 	top_sig = mt7530_read(priv, MT7531_TOP_SIG_SR);
 	hwstrap = mt7530_read(priv, MT7531_HWTRAP);
@@ -920,8 +908,6 @@ static const char *p5_intf_modes(unsigned int p5_interface)
 		return "PHY P4";
 	case P5_INTF_SEL_GMAC5:
 		return "GMAC5";
-	case P5_INTF_SEL_GMAC5_SGMII:
-		return "GMAC5_SGMII";
 	default:
 		return "unknown";
 	}
@@ -2470,6 +2456,12 @@ mt7531_setup(struct dsa_switch *ds)
 		return -ENODEV;
 	}
 
+	/* MT7531AE has got two SGMII units. One for port 5, one for port 6.
+	 * MT7531BE has got only one SGMII unit which is for port 6.
+	 */
+	val = mt7530_read(priv, MT7531_TOP_SIG_SR);
+	priv->p5_sgmii = !!(val & PAD_DUAL_SGMII_EN);
+
 	/* all MACs must be forced link-down before sw reset */
 	for (i = 0; i < MT7530_NUM_PORTS; i++)
 		mt7530_write(priv, MT7530_PMCR_P(i), MT7531_FORCE_LNK);
@@ -2479,21 +2471,18 @@ mt7531_setup(struct dsa_switch *ds)
 		     SYS_CTRL_PHY_RST | SYS_CTRL_SW_RST |
 		     SYS_CTRL_REG_RST);
 
-	mt7531_pll_setup(priv);
-
-	if (mt7531_dual_sgmii_supported(priv)) {
-		priv->p5_intf_sel = P5_INTF_SEL_GMAC5_SGMII;
-
+	if (!priv->p5_sgmii) {
+		mt7531_pll_setup(priv);
+	} else {
 		/* Let ds->user_mii_bus be able to access external phy. */
 		mt7530_rmw(priv, MT7531_GPIO_MODE1, MT7531_GPIO11_RG_RXD2_MASK,
 			   MT7531_EXT_P_MDC_11);
 		mt7530_rmw(priv, MT7531_GPIO_MODE1, MT7531_GPIO12_RG_RXD3_MASK,
 			   MT7531_EXT_P_MDIO_12);
-	} else {
-		priv->p5_intf_sel = P5_INTF_SEL_GMAC5;
 	}
-	dev_dbg(ds->dev, "P5 support %s interface\n",
-		p5_intf_modes(priv->p5_intf_sel));
+
+	if (!dsa_is_unused_port(ds, 5))
+		priv->p5_intf_sel = P5_INTF_SEL_GMAC5;
 
 	mt7530_rmw(priv, MT7531_GPIO_MODE0, MT7531_GPIO0_MASK,
 		   MT7531_GPIO0_INTERRUPT);
@@ -2553,11 +2542,6 @@ static void mt7530_mac_port_get_caps(struct dsa_switch *ds, int port,
 	}
 }
 
-static bool mt7531_is_rgmii_port(struct mt7530_priv *priv, u32 port)
-{
-	return (port == 5) && (priv->p5_intf_sel != P5_INTF_SEL_GMAC5_SGMII);
-}
-
 static void mt7531_mac_port_get_caps(struct dsa_switch *ds, int port,
 				     struct phylink_config *config)
 {
@@ -2570,7 +2554,7 @@ static void mt7531_mac_port_get_caps(struct dsa_switch *ds, int port,
 		break;
 
 	case 5: /* 2nd cpu port supports either rgmii or sgmii/8023z */
-		if (mt7531_is_rgmii_port(priv, port)) {
+		if (!priv->p5_sgmii) {
 			phy_interface_set_rgmii(config->supported_interfaces);
 			break;
 		}
@@ -2637,7 +2621,7 @@ static int mt7531_rgmii_setup(struct mt7530_priv *priv, u32 port,
 {
 	u32 val;
 
-	if (!mt7531_is_rgmii_port(priv, port)) {
+	if (priv->p5_sgmii) {
 		dev_err(priv->dev, "RGMII mode is not available for port %d\n",
 			port);
 		return -EINVAL;
@@ -2881,7 +2865,7 @@ mt7531_cpu_port_config(struct dsa_switch *ds, int port)
 
 	switch (port) {
 	case 5:
-		if (mt7531_is_rgmii_port(priv, port))
+		if (!priv->p5_sgmii)
 			interface = PHY_INTERFACE_MODE_RGMII;
 		else
 			interface = PHY_INTERFACE_MODE_2500BASEX;
@@ -3033,7 +3017,7 @@ mt753x_setup(struct dsa_switch *ds)
 		mt7530_free_irq_common(priv);
 
 	if (priv->create_sgmii) {
-		ret = priv->create_sgmii(priv, mt7531_dual_sgmii_supported(priv));
+		ret = priv->create_sgmii(priv);
 		if (ret && priv->irq)
 			mt7530_free_irq(priv);
 	}
diff --git a/drivers/net/dsa/mt7530.h b/drivers/net/dsa/mt7530.h
index 9cbf18efa416..80060cc740d2 100644
--- a/drivers/net/dsa/mt7530.h
+++ b/drivers/net/dsa/mt7530.h
@@ -687,7 +687,6 @@ enum p5_interface_select {
 	P5_INTF_SEL_PHY_P0,
 	P5_INTF_SEL_PHY_P4,
 	P5_INTF_SEL_GMAC5,
-	P5_INTF_SEL_GMAC5_SGMII,
 };
 
 struct mt7530_priv;
@@ -756,6 +755,8 @@ struct mt753x_info {
  *			registers
  * @p6_interface	Holding the current port 6 interface
  * @p5_intf_sel:	Holding the current port 5 interface select
+ * @p5_sgmii:		Flag for distinguishing if port 5 of the MT7531 switch
+ *			has got SGMII
  * @irq:		IRQ number of the switch
  * @irq_domain:		IRQ domain of the switch irq_chip
  * @irq_enable:		IRQ enable bits, synced to SYS_INT_EN
@@ -777,6 +778,7 @@ struct mt7530_priv {
 	phy_interface_t		p6_interface;
 	phy_interface_t		p5_interface;
 	enum p5_interface_select p5_intf_sel;
+	bool			p5_sgmii;
 	u8			mirror_rx;
 	u8			mirror_tx;
 	struct mt7530_port	ports[MT7530_NUM_PORTS];
@@ -786,7 +788,7 @@ struct mt7530_priv {
 	int irq;
 	struct irq_domain *irq_domain;
 	u32 irq_enable;
-	int (*create_sgmii)(struct mt7530_priv *priv, bool dual_sgmii);
+	int (*create_sgmii)(struct mt7530_priv *priv);
 	u8 active_cpu_ports;
 };
 
