SMC911X: Add chip auto detection

Refactor the smc911x driver to allow for detecting when the chip is missing.
I.e. the detect_chip() function is called earlier and will abort gracefully
when the Chip ID read returns all 1's.

Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Dirk Behme <dirk.behme@googlemail.com>
Acked-by: Ben Warren <biggerbadderben@gmail.com>

drivers/net/smc911x.c

@@ -146,10 +146,9 @@ static void smc911x_enable(struct eth_device *dev)
 
 static int smc911x_init(struct eth_device *dev, bd_t * bd)
 {
-	printf(DRIVERNAME ": initializing\n");
+	struct chip_id *id = dev->priv;
 
-	if (smc911x_detect_chip(dev))
-		goto err_out;
+        printf(DRIVERNAME ": detected %s controller\n", id->name);
 
 	smc911x_reset(dev);
 
@@ -162,9 +161,6 @@ static int smc911x_init(struct eth_device *dev, bd_t * bd)
 	smc911x_enable(dev);
 
 	return 0;
-
-err_out:
-	return -1;
 }
 
 static int smc911x_send(struct eth_device *dev,
@@ -268,6 +264,12 @@ int smc911x_initialize(u8 dev_num, int base_addr)
 	dev->recv = smc911x_rx;
 	sprintf(dev->name, "%s-%hu", DRIVERNAME, dev_num);
 
+	/* Try to detect chip. Will fail if not present. */
+	if (smc911x_detect_chip(dev)) {
+		free(dev);
+		return 0;
+	}
+
 	eth_register(dev);
 	return 0;
 }

drivers/net/smc911x.h

@@ -441,7 +441,10 @@ static int smc911x_detect_chip(struct eth_device *dev)
 	unsigned long val, i;
 
 	val = smc911x_reg_read(dev, BYTE_TEST);
-	if (val != 0x87654321) {
+	if (val == 0xffffffff) {
+		/* Special case -- no chip present */
+		return -1;
+	} else if (val != 0x87654321) {
 		printf(DRIVERNAME ": Invalid chip endian 0x%08lx\n", val);
 		return -1;
 	}
@@ -455,7 +458,7 @@ static int smc911x_detect_chip(struct eth_device *dev)
 		return -1;
 	}
 
-	printf(DRIVERNAME ": detected %s controller\n", chip_ids[i].name);
+	dev->priv = (void *)&chip_ids[i];
 
 	return 0;
 }