net: usb: ax88179_178a: allow optionally getting mac address from device tree

Adopt and integrate the feature to pass the MAC address via device tree
from asix_device.c (03fc5d4f) also to other ax88179 based asix chips.
E.g. the bootloader fills in local-mac-address and the driver will then
pick up and use this MAC address.
Signed-off-by: Peter Fink <pfink@christ-es.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/ax88179_178a.c

@@ -1214,6 +1214,29 @@ static int ax88179_led_setting(struct usbnet *dev)
 	return 0;
 }
 
+static void ax88179_get_mac_addr(struct usbnet *dev)
+{
+	u8 mac[ETH_ALEN];
+
+	/* Maybe the boot loader passed the MAC address via device tree */
+	if (!eth_platform_get_mac_address(&dev->udev->dev, mac)) {
+		netif_dbg(dev, ifup, dev->net,
+			  "MAC address read from device tree");
+	} else {
+		ax88179_read_cmd(dev, AX_ACCESS_MAC, AX_NODE_ID, ETH_ALEN,
+				 ETH_ALEN, mac);
+		netif_dbg(dev, ifup, dev->net,
+			  "MAC address read from ASIX chip");
+	}
+
+	if (is_valid_ether_addr(mac)) {
+		memcpy(dev->net->dev_addr, mac, ETH_ALEN);
+	} else {
+		netdev_info(dev->net, "invalid MAC address, using random\n");
+		eth_hw_addr_random(dev->net);
+	}
+}
+
 static int ax88179_bind(struct usbnet *dev, struct usb_interface *intf)
 {
 	u8 buf[5];
@@ -1240,8 +1263,8 @@ static int ax88179_bind(struct usbnet *dev, struct usb_interface *intf)
 	ax88179_write_cmd(dev, AX_ACCESS_MAC, AX_CLK_SELECT, 1, 1, tmp);
 	msleep(100);
 
-	ax88179_read_cmd(dev, AX_ACCESS_MAC, AX_NODE_ID, ETH_ALEN,
-			 ETH_ALEN, dev->net->dev_addr);
+	/* Read MAC address from DTB or asix chip */
+	ax88179_get_mac_addr(dev);
 	memcpy(dev->net->perm_addr, dev->net->dev_addr, ETH_ALEN);
 
 	/* RX bulk configuration */
@@ -1541,8 +1564,8 @@ static int ax88179_reset(struct usbnet *dev)
 	/* Ethernet PHY Auto Detach*/
 	ax88179_auto_detach(dev, 0);
 
-	ax88179_read_cmd(dev, AX_ACCESS_MAC, AX_NODE_ID, ETH_ALEN, ETH_ALEN,
-			 dev->net->dev_addr);
+	/* Read MAC address from DTB or asix chip */
+	ax88179_get_mac_addr(dev);
 
 	/* RX bulk configuration */
 	memcpy(tmp, &AX88179_BULKIN_SIZE[0], 5);