diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index 8e1574c63954..252089929eb9 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -666,6 +666,15 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 		goto err_read_skb;
 	}
 
+	/* It seems that accessing the switch's internal PHYs via management
+	 * packets still uses the MDIO bus within the switch internally, and
+	 * these accesses can conflict with external MDIO accesses to other
+	 * devices on the MDIO bus.
+	 * We therefore need to lock the MDIO bus onto which the switch is
+	 * connected.
+	 */
+	mutex_lock(&priv->bus->mdio_lock);
+
 	/* Actually start the request:
 	 * 1. Send mdio master packet
 	 * 2. Busy Wait for mdio master command
@@ -678,6 +687,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 	mgmt_master = priv->mgmt_master;
 	if (!mgmt_master) {
 		mutex_unlock(&mgmt_eth_data->mutex);
+		mutex_unlock(&priv->bus->mdio_lock);
 		ret = -EINVAL;
 		goto err_mgmt_master;
 	}
@@ -765,6 +775,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 				    QCA8K_ETHERNET_TIMEOUT);
 
 	mutex_unlock(&mgmt_eth_data->mutex);
+	mutex_unlock(&priv->bus->mdio_lock);
 
 	return ret;