dt-bindings: net: mdio: add reset-post-delay-us property

Add "reset-post-delay-us" parameter to MDIO bus properties,
so it's possible to add a delay after reset deassert.
This is optional in case external hardware slows down
release of the reset signal.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/mdio.yaml

@@ -39,6 +39,13 @@ properties:
       and must therefore be appropriately determined based on all devices
       requirements (maximum value of all per-device RESET pulse widths).
 
+  reset-post-delay-us:
+    description:
+      Delay after reset deassert in microseconds. It applies to all MDIO
+      devices and it's determined by how fast all devices are ready for
+      communication. This delay happens just before e.g. Ethernet PHY
+      type ID auto detection.
+
   clock-frequency:
     description:
       Desired MDIO bus clock frequency in Hz. Values greater than IEEE 802.3