net: dsa: mv88e6xxx: Refactor mv88e6352 SERDES code into an op

The mv88e6390 family has a different SERDES implementation. Refactor
the mv88e6352 code into an ops function, so we can later add the
mv88e6390 code.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/serdes.c

@@ -0,0 +1,75 @@
+/*
+ * Marvell 88E6xxx SERDES manipulation, via SMI bus
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2017 Andrew Lunn <andrew@lunn.ch>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/mii.h>
+
+#include "mv88e6xxx.h"
+#include "phy.h"
+#include "port.h"
+#include "serdes.h"
+
+static int mv88e6352_serdes_read(struct mv88e6xxx_chip *chip, int reg,
+				 u16 *val)
+{
+	return mv88e6xxx_phy_page_read(chip, MV88E6352_ADDR_SERDES,
+				       MV88E6352_SERDES_PAGE_FIBER,
+				       reg, val);
+}
+
+static int mv88e6352_serdes_write(struct mv88e6xxx_chip *chip, int reg,
+				  u16 val)
+{
+	return mv88e6xxx_phy_page_write(chip, MV88E6352_ADDR_SERDES,
+					MV88E6352_SERDES_PAGE_FIBER,
+					reg, val);
+}
+
+static int mv88e6352_serdes_power_set(struct mv88e6xxx_chip *chip, bool on)
+{
+	u16 val, new_val;
+	int err;
+
+	err = mv88e6352_serdes_read(chip, MII_BMCR, &val);
+	if (err)
+		return err;
+
+	if (on)
+		new_val = val & ~BMCR_PDOWN;
+	else
+		new_val = val | BMCR_PDOWN;
+
+	if (val != new_val)
+		err = mv88e6352_serdes_write(chip, MII_BMCR, new_val);
+
+	return err;
+}
+
+int mv88e6352_serdes_power(struct mv88e6xxx_chip *chip, int port, bool on)
+{
+	int err;
+	u8 cmode;
+
+	err = mv88e6xxx_port_get_cmode(chip, port, &cmode);
+	if (err)
+		return err;
+
+	if ((cmode == PORT_STATUS_CMODE_100BASE_X) ||
+	    (cmode == PORT_STATUS_CMODE_1000BASE_X) ||
+	    (cmode == PORT_STATUS_CMODE_SGMII)) {
+		err = mv88e6352_serdes_power_set(chip, on);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}