diff --git a/include/linux/phy.h b/include/linux/phy.h
index 60d2b26026a2..852743f07e3e 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -496,6 +496,11 @@ struct macsec_ops;
  * @mac_managed_pm: Set true if MAC driver takes of suspending/resuming PHY
  * @state: State of the PHY for management purposes
  * @dev_flags: Device-specific flags used by the PHY driver.
+ *		Bits [15:0] are free to use by the PHY driver to communicate
+ *			    driver specific behavior.
+ *		Bits [23:16] are currently reserved for future use.
+ *		Bits [31:24] are reserved for defining generic
+ *			     PHY driver behavior.
  * @irq: IRQ number of the PHY's interrupt (-1 if none)
  * @phy_timer: The timer for handling the state machine
  * @phylink: Pointer to phylink instance for this PHY