net: ks8851: Use 16-bit writes to program MAC address

On the SPI variant of KS8851, the MAC address can be programmed with
either 8/16/32-bit writes. To make it easier to support the 16-bit
parallel option of KS8851 too, switch both the MAC address programming
and readout to 16-bit operations.

Remove ks8851_wrreg8() as it is not used anywhere anymore.

There should be no functional change.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Petr Stetiar <ynezz@true.cz>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/micrel/ks8851.c

@@ -185,36 +185,6 @@ static void ks8851_wrreg16(struct ks8851_net *ks, unsigned reg, unsigned val)
 		netdev_err(ks->netdev, "spi_sync() failed\n");
 }
 
-/**
- * ks8851_wrreg8 - write 8bit register value to chip
- * @ks: The chip state
- * @reg: The register address
- * @val: The value to write
- *
- * Issue a write to put the value @val into the register specified in @reg.
- */
-static void ks8851_wrreg8(struct ks8851_net *ks, unsigned reg, unsigned val)
-{
-	struct spi_transfer *xfer = &ks->spi_xfer1;
-	struct spi_message *msg = &ks->spi_msg1;
-	__le16 txb[2];
-	int ret;
-	int bit;
-
-	bit = 1 << (reg & 3);
-
-	txb[0] = cpu_to_le16(MK_OP(bit, reg) | KS_SPIOP_WR);
-	txb[1] = val;
-
-	xfer->tx_buf = txb;
-	xfer->rx_buf = NULL;
-	xfer->len = 3;
-
-	ret = spi_sync(ks->spidev, msg);
-	if (ret < 0)
-		netdev_err(ks->netdev, "spi_sync() failed\n");
-}
-
 /**
  * ks8851_rdreg - issue read register command and return the data
  * @ks: The device state
@@ -349,6 +319,7 @@ static void ks8851_set_powermode(struct ks8851_net *ks, unsigned pwrmode)
 static int ks8851_write_mac_addr(struct net_device *dev)
 {
 	struct ks8851_net *ks = netdev_priv(dev);
+	u16 val;
 	int i;
 
 	mutex_lock(&ks->lock);
@@ -358,8 +329,12 @@ static int ks8851_write_mac_addr(struct net_device *dev)
 	 * 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]);
+
+	for (i = 0; i < ETH_ALEN; i += 2) {
+		val = (dev->dev_addr[i] << 8) | dev->dev_addr[i + 1];
+		ks8851_wrreg16(ks, KS_MAR(i), val);
+	}
+
 	if (!netif_running(dev))
 		ks8851_set_powermode(ks, PMECR_PM_SOFTDOWN);
 
@@ -377,12 +352,16 @@ static int ks8851_write_mac_addr(struct net_device *dev)
 static void ks8851_read_mac_addr(struct net_device *dev)
 {
 	struct ks8851_net *ks = netdev_priv(dev);
+	u16 reg;
 	int i;
 
 	mutex_lock(&ks->lock);
 
-	for (i = 0; i < ETH_ALEN; i++)
-		dev->dev_addr[i] = ks8851_rdreg8(ks, KS_MAR(i));
+	for (i = 0; i < ETH_ALEN; i += 2) {
+		reg = ks8851_rdreg16(ks, KS_MAR(i));
+		dev->dev_addr[i] = reg >> 8;
+		dev->dev_addr[i + 1] = reg & 0xff;
+	}
 
 	mutex_unlock(&ks->lock);
 }

drivers/net/ethernet/micrel/ks8851.h

@@ -19,7 +19,7 @@
 #define CCR_32PIN				(1 << 0)    /* KSZ8851SNL    */
 
 /* MAC address registers */
-#define KS_MAR(_m)				(0x15 - (_m))
+#define KS_MAR(_m)				(0x14 - (_m))
 #define KS_MARL					0x10
 #define KS_MARM					0x12
 #define KS_MARH					0x14