net: dsa: mv88e6xxx: add EEPROM support to 6390

The Marvell 6352 chip has a 8-bit address/16-bit data EEPROM access.
The Marvell 6390 chip has a 16-bit address/8-bit data EEPROM access.

This patch implements the 8-bit data EEPROM access in the mv88e6xxx
driver and adds its support to chips of the 6390 family.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/global2.c

@@ -218,7 +218,8 @@ static int mv88e6xxx_g2_clear_pot(struct mv88e6xxx_chip *chip)
 }
 
 /* Offset 0x14: EEPROM Command
- * Offset 0x15: EEPROM Data
+ * Offset 0x15: EEPROM Data (for 16-bit data access)
+ * Offset 0x15: EEPROM Addr (for 8-bit data access)
  */
 
 static int mv88e6xxx_g2_eeprom_wait(struct mv88e6xxx_chip *chip)
@@ -239,6 +240,50 @@ static int mv88e6xxx_g2_eeprom_cmd(struct mv88e6xxx_chip *chip, u16 cmd)
 	return mv88e6xxx_g2_eeprom_wait(chip);
 }
 
+static int mv88e6xxx_g2_eeprom_read8(struct mv88e6xxx_chip *chip,
+				     u16 addr, u8 *data)
+{
+	u16 cmd = GLOBAL2_EEPROM_CMD_OP_READ;
+	int err;
+
+	err = mv88e6xxx_g2_eeprom_wait(chip);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g2_write(chip, GLOBAL2_EEPROM_ADDR, addr);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g2_eeprom_cmd(chip, cmd);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g2_read(chip, GLOBAL2_EEPROM_CMD, &cmd);
+	if (err)
+		return err;
+
+	*data = cmd & 0xff;
+
+	return 0;
+}
+
+static int mv88e6xxx_g2_eeprom_write8(struct mv88e6xxx_chip *chip,
+				      u16 addr, u8 data)
+{
+	u16 cmd = GLOBAL2_EEPROM_CMD_OP_WRITE | GLOBAL2_EEPROM_CMD_WRITE_EN;
+	int err;
+
+	err = mv88e6xxx_g2_eeprom_wait(chip);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_g2_write(chip, GLOBAL2_EEPROM_ADDR, addr);
+	if (err)
+		return err;
+
+	return mv88e6xxx_g2_eeprom_cmd(chip, cmd | data);
+}
+
 static int mv88e6xxx_g2_eeprom_read16(struct mv88e6xxx_chip *chip,
 				      u8 addr, u16 *data)
 {
@@ -273,6 +318,52 @@ static int mv88e6xxx_g2_eeprom_write16(struct mv88e6xxx_chip *chip,
 	return mv88e6xxx_g2_eeprom_cmd(chip, cmd);
 }
 
+int mv88e6xxx_g2_get_eeprom8(struct mv88e6xxx_chip *chip,
+			     struct ethtool_eeprom *eeprom, u8 *data)
+{
+	unsigned int offset = eeprom->offset;
+	unsigned int len = eeprom->len;
+	int err;
+
+	eeprom->len = 0;
+
+	while (len) {
+		err = mv88e6xxx_g2_eeprom_read8(chip, offset, data);
+		if (err)
+			return err;
+
+		eeprom->len++;
+		offset++;
+		data++;
+		len--;
+	}
+
+	return 0;
+}
+
+int mv88e6xxx_g2_set_eeprom8(struct mv88e6xxx_chip *chip,
+			     struct ethtool_eeprom *eeprom, u8 *data)
+{
+	unsigned int offset = eeprom->offset;
+	unsigned int len = eeprom->len;
+	int err;
+
+	eeprom->len = 0;
+
+	while (len) {
+		err = mv88e6xxx_g2_eeprom_write8(chip, offset, *data);
+		if (err)
+			return err;
+
+		eeprom->len++;
+		offset++;
+		data++;
+		len--;
+	}
+
+	return 0;
+}
+
 int mv88e6xxx_g2_get_eeprom16(struct mv88e6xxx_chip *chip,
 			      struct ethtool_eeprom *eeprom, u8 *data)
 {