diff --git a/target/linux/ath79/dts/ar7100.dtsi b/target/linux/ath79/dts/ar7100.dtsi
index 8994a7d688..6402657841 100644
--- a/target/linux/ath79/dts/ar7100.dtsi
+++ b/target/linux/ath79/dts/ar7100.dtsi
@@ -182,6 +182,7 @@
 
 	resets = <&rst 9>;
 	reset-names = "mac";
+	qca,mac-idx = <0>;
 };
 
 &mdio1 {
@@ -201,4 +202,5 @@
 
 	resets = <&rst 13>;
 	reset-names = "mac";
+	qca,mac-idx = <1>;
 };
diff --git a/target/linux/ath79/dts/ar9132.dtsi b/target/linux/ath79/dts/ar9132.dtsi
index 9d8ddcf9ba..2264994279 100644
--- a/target/linux/ath79/dts/ar9132.dtsi
+++ b/target/linux/ath79/dts/ar9132.dtsi
@@ -193,4 +193,5 @@
 	pll-handle = <&pll>;
 	resets = <&rst 9>;
 	reset-names = "mac";
+	qca,mac-idx = <0>;
 };
diff --git a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
index 377b9f8fe2..9aac1998a8 100644
--- a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
+++ b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
@@ -154,6 +154,8 @@ struct ag71xx {
 	struct ag71xx_ring	rx_ring ____cacheline_aligned;
 	struct ag71xx_ring	tx_ring ____cacheline_aligned;
 
+	int			mac_idx;
+
 	u16			desc_pktlen_mask;
 	u16			rx_buf_size;
 	u8			rx_buf_offset;
diff --git a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
index 1e0bb6937f..d029197d4c 100644
--- a/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
+++ b/target/linux/ath79/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
@@ -529,6 +529,60 @@ static void ath79_set_pll(struct ag71xx *ag)
 	udelay(100);
 }
 
+static void ath79_mii_ctrl_set_if(struct ag71xx *ag, unsigned int mii_if)
+{
+	u32 t;
+
+	t = __raw_readl(ag->mii_base);
+	t &= ~(AR71XX_MII_CTRL_IF_MASK);
+	t |= (mii_if & AR71XX_MII_CTRL_IF_MASK);
+	__raw_writel(t, ag->mii_base);
+}
+
+static void ath79_mii0_ctrl_set_if(struct ag71xx *ag)
+{
+	unsigned int mii_if;
+
+	switch (ag->phy_if_mode) {
+	case PHY_INTERFACE_MODE_MII:
+		mii_if = AR71XX_MII0_CTRL_IF_MII;
+		break;
+	case PHY_INTERFACE_MODE_GMII:
+		mii_if = AR71XX_MII0_CTRL_IF_GMII;
+		break;
+	case PHY_INTERFACE_MODE_RGMII:
+		mii_if = AR71XX_MII0_CTRL_IF_RGMII;
+		break;
+	case PHY_INTERFACE_MODE_RMII:
+		mii_if = AR71XX_MII0_CTRL_IF_RMII;
+		break;
+	default:
+		WARN(1, "Impossible PHY mode defined.\n");
+		return;
+	}
+
+	ath79_mii_ctrl_set_if(ag, mii_if);
+}
+
+static void ath79_mii1_ctrl_set_if(struct ag71xx *ag)
+{
+	unsigned int mii_if;
+
+	switch (ag->phy_if_mode) {
+	case PHY_INTERFACE_MODE_RMII:
+		mii_if = AR71XX_MII1_CTRL_IF_RMII;
+		break;
+	case PHY_INTERFACE_MODE_RGMII:
+		mii_if = AR71XX_MII1_CTRL_IF_RGMII;
+		break;
+	default:
+		WARN(1, "Impossible PHY mode defined.\n");
+		return;
+	}
+
+	ath79_mii_ctrl_set_if(ag, mii_if);
+}
+
 static void ath79_mii_ctrl_set_speed(struct ag71xx *ag)
 {
 	unsigned int mii_speed;
@@ -1427,6 +1481,20 @@ static int ag71xx_probe(struct platform_device *pdev)
 		goto err_free;
 	}
 
+	if (of_property_read_u32(np, "qca,mac-idx", &ag->mac_idx))
+		ag->mac_idx = -1;
+	if (ag->mii_base)
+		switch (ag->mac_idx) {
+		case 0:
+			ath79_mii0_ctrl_set_if(ag);
+			break;
+		case 1:
+			ath79_mii1_ctrl_set_if(ag);
+			break;
+		default:
+			break;
+		}
+
 	netif_napi_add(dev, &ag->napi, ag71xx_poll, AG71XX_NAPI_WEIGHT);
 
 	ag71xx_wr(ag, AG71XX_REG_MAC_CFG1, 0);