KSZ8851-SNL: Fix MAC address change problem

When device is off it is under power saving mode. Changing the MAC address
in that situation will result in the device not communicating as the first
write to the MAC address register is not executed.

Signed-off-by: Tristram Ha <Tristram.Ha@micrel.com>
[ben@simtec.co.uk: cleaned up header]
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/micrel/ks8851.c b/drivers/net/ethernet/micrel/ks8851.c
index d1669bc..208e25a 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -343,6 +343,26 @@
 }
 
 /**
+ * ks8851_set_powermode - set power mode of the device
+ * @ks: The device state
+ * @pwrmode: The power mode value to write to KS_PMECR.
+ *
+ * Change the power mode of the chip.
+ */
+static void ks8851_set_powermode(struct ks8851_net *ks, unsigned pwrmode)
+{
+	unsigned pmecr;
+
+	netif_dbg(ks, hw, ks->netdev, "setting power mode %d\n", pwrmode);
+
+	pmecr = ks8851_rdreg16(ks, KS_PMECR);
+	pmecr &= ~PMECR_PM_MASK;
+	pmecr |= pwrmode;
+
+	ks8851_wrreg16(ks, KS_PMECR, pmecr);
+}
+
+/**
  * ks8851_write_mac_addr - write mac address to device registers
  * @dev: The network device
  *
@@ -358,8 +378,15 @@
 
 	mutex_lock(&ks->lock);
 
+	/*
+	 * Wake up chip in case it was powered off when stopped; otherwise,
+	 * the first write to the MAC address does not take effect.
+	 */
+	ks8851_set_powermode(ks, PMECR_PM_NORMAL);
 	for (i = 0; i < ETH_ALEN; i++)
 		ks8851_wrreg8(ks, KS_MAR(i), dev->dev_addr[i]);
+	if (!netif_running(dev))
+		ks8851_set_powermode(ks, PMECR_PM_SOFTDOWN);
 
 	mutex_unlock(&ks->lock);
 
@@ -765,26 +792,6 @@
 }
 
 /**
- * ks8851_set_powermode - set power mode of the device
- * @ks: The device state
- * @pwrmode: The power mode value to write to KS_PMECR.
- *
- * Change the power mode of the chip.
- */
-static void ks8851_set_powermode(struct ks8851_net *ks, unsigned pwrmode)
-{
-	unsigned pmecr;
-
-	netif_dbg(ks, hw, ks->netdev, "setting power mode %d\n", pwrmode);
-
-	pmecr = ks8851_rdreg16(ks, KS_PMECR);
-	pmecr &= ~PMECR_PM_MASK;
-	pmecr |= pwrmode;
-
-	ks8851_wrreg16(ks, KS_PMECR, pmecr);
-}
-
-/**
  * ks8851_net_open - open network device
  * @dev: The network device being opened.
  *