net: dsa: mv88e6xxx: lookup switch name

All the mv88e6xxx drivers use the exact same code in their probe
function to lookup the switch name given its ID. Thus introduce a
mv88e6xxx_switch_id structure and a mv88e6xxx_lookup_name function in
the common mv88e6xxx code.

In the meantime make __mv88e6xxx_reg_{read,write} static since we do not
need to expose these low-level r/w routines anymore.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6171.c b/drivers/net/dsa/mv88e6171.c
index 1bd876e..54aa000 100644
--- a/drivers/net/dsa/mv88e6171.c
+++ b/drivers/net/dsa/mv88e6171.c
@@ -17,27 +17,17 @@
 #include <net/dsa.h>
 #include "mv88e6xxx.h"
 
+static const struct mv88e6xxx_switch_id mv88e6171_table[] = {
+	{ PORT_SWITCH_ID_6171, "Marvell 88E6171" },
+	{ PORT_SWITCH_ID_6175, "Marvell 88E6175" },
+	{ PORT_SWITCH_ID_6350, "Marvell 88E6350" },
+	{ PORT_SWITCH_ID_6351, "Marvell 88E6351" },
+};
+
 static char *mv88e6171_probe(struct device *host_dev, int sw_addr)
 {
-	struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
-	int ret;
-
-	if (bus == NULL)
-		return NULL;
-
-	ret = __mv88e6xxx_reg_read(bus, sw_addr, REG_PORT(0), PORT_SWITCH_ID);
-	if (ret >= 0) {
-		if ((ret & 0xfff0) == PORT_SWITCH_ID_6171)
-			return "Marvell 88E6171";
-		if ((ret & 0xfff0) == PORT_SWITCH_ID_6175)
-			return "Marvell 88E6175";
-		if ((ret & 0xfff0) == PORT_SWITCH_ID_6350)
-			return "Marvell 88E6350";
-		if ((ret & 0xfff0) == PORT_SWITCH_ID_6351)
-			return "Marvell 88E6351";
-	}
-
-	return NULL;
+	return mv88e6xxx_lookup_name(host_dev, sw_addr, mv88e6171_table,
+				     ARRAY_SIZE(mv88e6171_table));
 }
 
 static int mv88e6171_setup_global(struct dsa_switch *ds)