net: phy: dp83869: Update port-mirroring to read straps

The device tree may not have the property set for port mirroring
because the hardware may have it strapped. If the property is not in the
DT then check the straps and set the port mirroring bit appropriately.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/dp83869.c

@@ -66,6 +66,7 @@
 
 /* STRAP_STS1 bits */
 #define DP83869_STRAP_STS1_RESERVED		BIT(11)
+#define DP83869_STRAP_MIRROR_ENABLED           BIT(12)
 
 /* PHYCTRL bits */
 #define DP83869_RX_FIFO_SHIFT	12
@@ -191,10 +192,18 @@ static int dp83869_of_init(struct phy_device *phydev)
 	else if (of_property_read_bool(of_node, "ti,min-output-impedance"))
 		dp83869->io_impedance = DP83869_IO_MUX_CFG_IO_IMPEDANCE_MIN;
 
-	if (of_property_read_bool(of_node, "enet-phy-lane-swap"))
+	if (of_property_read_bool(of_node, "enet-phy-lane-swap")) {
+		dp83869->port_mirroring = DP83869_PORT_MIRRORING_EN;
+	} else {
+		/* If the lane swap is not in the DT then check the straps */
+		ret = phy_read_mmd(phydev, DP83869_DEVADDR, DP83869_STRAP_STS1);
+		if (ret < 0)
+			return ret;
+		if (ret & DP83869_STRAP_MIRROR_ENABLED)
 			dp83869->port_mirroring = DP83869_PORT_MIRRORING_EN;
 		else
 			dp83869->port_mirroring = DP83869_PORT_MIRRORING_DIS;
+	}
 
 	if (of_property_read_u32(of_node, "rx-fifo-depth",
 				 &dp83869->rx_fifo_depth))