Index: head/sys/dev/fdt/simplebus.c
===================================================================
--- head/sys/dev/fdt/simplebus.c
+++ head/sys/dev/fdt/simplebus.c
@@ -265,6 +265,15 @@
 
 	if ((ndi = simplebus_setup_dinfo(dev, node, di)) == NULL)
 		return (NULL);
+
+	/*
+	 * If the order is unspecified, use the cell-index field, if available.
+	 * The cell-index property is not part of any standard, but is widely
+	 * used in NXP/Freescale and Marvell device trees.
+	 */
+	if (order == -1)
+		OF_getencprop(node, "cell-index", &order, sizeof(order));
+
 	cdev = device_add_child_ordered(dev, order, name, unit);
 	if (cdev == NULL) {
 		device_printf(dev, "<%s>: device_add_child failed\n",