net: fec: add phy-reset-duration for device tree probe

Different boards may require different phy reset duration. Add property
phy-reset-duration for device tree probe, so that the boards that need
a longer reset duration can specify it in their device tree.

Signed-off-by: Shawn Guo <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/fsl-fec.txt

···
 Optional properties:
 - local-mac-address : 6 bytes, mac address
 - phy-reset-gpios : Should specify the gpio for phy reset
+- phy-reset-duration : Reset duration in milliseconds.  Should present
+  only if property "phy-reset-gpios" is available.  Missing the property
+  will have the duration be 1 millisecond.  Numbers greater than 1000 are
+  invalid and 1 millisecond will be used instead.
 
 Example:
 

drivers/net/ethernet/freescale/fec.c

···
 static void __devinit fec_reset_phy(struct platform_device *pdev)
 {
 	int err, phy_reset;
+	int msec = 1;
 	struct device_node *np = pdev->dev.of_node;
 
 	if (!np)
 		return;
+
+	of_property_read_u32(np, "phy-reset-duration", &msec);
+	/* A sane reset duration should not be longer than 1s */
+	if (msec > 1000)
+		msec = 1;
 
 	phy_reset = of_get_named_gpio(np, "phy-reset-gpios", 0);
 	err = devm_gpio_request_one(&pdev->dev, phy_reset,
···
 		pr_debug("FEC: failed to get gpio phy-reset: %d\n", err);
 		return;
 	}
-	msleep(1);
+	msleep(msec);
 	gpio_set_value(phy_reset, 1);
 }
 #else /* CONFIG_OF */