phylib: Add device reset delay support

Some PHYs need a minimum time after the reset gpio was asserted and/or
deasserted. To ensure we meet these timing requirements add two new
optional devicetree parameters for the phy: reset-delay-us and
reset-post-delay-us.

Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/of/of_mdio.c

@@ -77,6 +77,10 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
 	if (of_property_read_bool(child, "broken-turn-around"))
 		mdio->phy_ignore_ta_mask |= 1 << addr;
 
+	of_property_read_u32(child, "reset-delay-us", &phy->mdio.reset_delay);
+	of_property_read_u32(child, "reset-post-delay-us",
+			     &phy->mdio.reset_post_delay);
+
 	/* Associate the OF node with the device structure so it
 	 * can be looked up later */
 	of_node_get(child);