net: dsa: Move phy page access functions into shared code

These functions could in future be used by other drivers. Move them
into the shared area.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6xxx.c b/drivers/net/dsa/mv88e6xxx.c
index 9db5b40..df727e1 100644
--- a/drivers/net/dsa/mv88e6xxx.c
+++ b/drivers/net/dsa/mv88e6xxx.c
@@ -1201,6 +1201,40 @@
 	return 0;
 }
 
+int mv88e6xxx_phy_page_read(struct dsa_switch *ds, int port, int page, int reg)
+{
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+	int ret;
+
+	mutex_lock(&ps->phy_mutex);
+	ret = mv88e6xxx_phy_write_indirect(ds, port, 0x16, page);
+	if (ret < 0)
+		goto error;
+	ret = mv88e6xxx_phy_read_indirect(ds, port, reg);
+error:
+	mv88e6xxx_phy_write_indirect(ds, port, 0x16, 0x0);
+	mutex_unlock(&ps->phy_mutex);
+	return ret;
+}
+
+int mv88e6xxx_phy_page_write(struct dsa_switch *ds, int port, int page,
+			     int reg, int val)
+{
+	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
+	int ret;
+
+	mutex_lock(&ps->phy_mutex);
+	ret = mv88e6xxx_phy_write_indirect(ds, port, 0x16, page);
+	if (ret < 0)
+		goto error;
+
+	ret = mv88e6xxx_phy_write_indirect(ds, port, reg, val);
+error:
+	mv88e6xxx_phy_write_indirect(ds, port, 0x16, 0x0);
+	mutex_unlock(&ps->phy_mutex);
+	return ret;
+}
+
 static int __init mv88e6xxx_init(void)
 {
 #if IS_ENABLED(CONFIG_NET_DSA_MV88E6131)