+/**
+ * mdiobus_write_nested - Nested version of the mdiobus_write function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
+{
+ int err;
+
+ BUG_ON(in_interrupt());
+
+ mutex_lock_nested(&bus->mdio_lock, SINGLE_DEPTH_NESTING);
+ err = bus->write(bus, addr, regnum, val);
+ mutex_unlock(&bus->mdio_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(mdiobus_write_nested);
+