diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index fdf8221f46fa..e5c25beae21e 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -565,7 +565,10 @@ int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
 
 	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 
-	retval = bus->read(bus, addr, regnum);
+	if (bus->read)
+		retval = bus->read(bus, addr, regnum);
+	else
+		retval = -EOPNOTSUPP;
 
 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
 
@@ -590,7 +593,10 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 
 	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 
-	err = bus->write(bus, addr, regnum, val);
+	if (bus->write)
+		err = bus->write(bus, addr, regnum, val);
+	else
+		err = -EOPNOTSUPP;
 
 	trace_mdio_access(bus, 0, addr, regnum, val, err);