linux-kernel - [PATCH] net: usb: asix: allow optionally getting mac address from device tree

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Message-Id: <20180625080108.32441-1-marcel@ziswiler.com>
Date:   Mon, 25 Jun 2018 10:01:08 +0200
From:   Marcel Ziswiler <marcel@...wiler.com>
To:     netdev@...r.kernel.org
Cc:     Oliver Neukum <oneukum@...e.com>,
        Marcel Ziswiler <marcel.ziswiler@...adex.com>,
        linux-usb@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
        Dean Jenkins <Dean_Jenkins@...tor.com>,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: [PATCH] net: usb: asix: allow optionally getting mac address from device tree

From: Marcel Ziswiler <marcel.ziswiler@...adex.com>

For Embedded use where e.g. AX88772B chips may be used without external
EEPROMs the boot loader may choose to pass the MAC address to be used
via device tree. Therefore, allow for optionally getting the MAC
address from device tree data e.g. as follows (excerpt from a T30 based
board, local-mac-address to be filled in by boot loader):

/* EHCI instance 1: USB2_DP/N -> AX88772B */
usb@...04000 {
	status = "okay";
	#address-cells = <1>;
	#size-cells = <0>;
	asix@1 {
		reg = <1>;
		local-mac-address = [00 00 00 00 00 00];
	};
};

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@...adex.com>

---

 drivers/net/usb/asix.h         |  1 +
 drivers/net/usb/asix_devices.c | 39 ++++++++++++++++++++++++---------------
 2 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h
index 9a4171b90947..c8161960cef2 100644
--- a/drivers/net/usb/asix.h
+++ b/drivers/net/usb/asix.h
@@ -37,6 +37,7 @@
 #include <linux/usb/usbnet.h>
 #include <linux/slab.h>
 #include <linux/if_vlan.h>
+#include <linux/of_net.h>
 
 #define DRIVER_VERSION "22-Dec-2011"
 #define DRIVER_NAME "asix"
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 3d4f7959dabb..a88d65dfc64c 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -690,25 +690,34 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
 	u8 buf[ETH_ALEN], chipcode = 0;
 	u32 phyid;
 	struct asix_common_private *priv;
+	const u8 *mac_addr;
 
-	usbnet_get_endpoints(dev,intf);
+	usbnet_get_endpoints(dev, intf);
 
-	/* Get the MAC address */
-	if (dev->driver_info->data & FLAG_EEPROM_MAC) {
-		for (i = 0; i < (ETH_ALEN >> 1); i++) {
-			ret = asix_read_cmd(dev, AX_CMD_READ_EEPROM, 0x04 + i,
-					    0, 2, buf + i * 2, 0);
-			if (ret < 0)
-				break;
-		}
+	/* Maybe the boot loader passed the MAC address via device tree */
+	mac_addr = of_get_mac_address(dev->udev->dev.of_node);
+	if (mac_addr) {
+		memcpy(buf, mac_addr, ETH_ALEN);
 	} else {
-		ret = asix_read_cmd(dev, AX_CMD_READ_NODE_ID,
-				0, 0, ETH_ALEN, buf, 0);
-	}
+		/* Try getting the MAC address from EEPROM */
+		if (dev->driver_info->data & FLAG_EEPROM_MAC) {
+			for (i = 0; i < (ETH_ALEN >> 1); i++) {
+				ret = asix_read_cmd(dev, AX_CMD_READ_EEPROM,
+						    0x04 + i, 0, 2, buf + i * 2,
+						    0);
+				if (ret < 0)
+					break;
+			}
+		} else {
+			ret = asix_read_cmd(dev, AX_CMD_READ_NODE_ID,
+					    0, 0, ETH_ALEN, buf, 0);
+		}
 
-	if (ret < 0) {
-		netdev_dbg(dev->net, "Failed to read MAC address: %d\n", ret);
-		return ret;
+		if (ret < 0) {
+			netdev_dbg(dev->net, "Failed to read MAC address: %d\n",
+				   ret);
+			return ret;
+		}
 	}
 
 	asix_set_netdev_dev_addr(dev, buf);
-- 
2.14.4