diff --git a/drivers/net/phy/mdio-mux-bcm-iproc.c b/drivers/net/phy/mdio-mux-bcm-iproc.c
index 9b31670548433276a431458b69e515aa62debe7f..4a253c28edbc7fc91796611204ec8eab76294519 100644
--- a/drivers/net/phy/mdio-mux-bcm-iproc.c
+++ b/drivers/net/phy/mdio-mux-bcm-iproc.c
@@ -22,6 +22,9 @@
 #include <linux/mdio-mux.h>
 #include <linux/delay.h>
 
+#define MDIO_SCAN_CTRL_OFFSET		0x008
+#define MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR	28
+
 #define MDIO_PARAM_OFFSET		0x23c
 #define MDIO_PARAM_MIIM_CYCLE		29
 #define MDIO_PARAM_INTERNAL_SEL		25
@@ -53,6 +56,16 @@ struct iproc_mdiomux_desc {
 	struct mii_bus *mii_bus;
 };
 
+static void mdio_mux_iproc_config(struct iproc_mdiomux_desc *md)
+{
+	u32 val;
+
+	/* Disable external mdio master access */
+	val = readl(md->base + MDIO_SCAN_CTRL_OFFSET);
+	val |= BIT(MDIO_SCAN_CTRL_OVRIDE_EXT_MSTR);
+	writel(val, md->base + MDIO_SCAN_CTRL_OFFSET);
+}
+
 static int iproc_mdio_wait_for_idle(void __iomem *base, bool result)
 {
 	unsigned int timeout = 1000; /* loop for 1s */
@@ -216,6 +229,8 @@ static int mdio_mux_iproc_probe(struct platform_device *pdev)
 		goto out_register;
 	}
 
+	mdio_mux_iproc_config(md);
+
 	dev_info(md->dev, "iProc mdiomux registered\n");
 	return 0;