net: mscc: ocelot: add a type definition for REW_TAG_CFG_TAG_CFG

This is a cosmetic patch which clarifies what are the port tagging
options for Ocelot switches.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot.c

@@ -166,7 +166,7 @@ static void ocelot_port_set_native_vlan(struct ocelot *ocelot, int port,
 					struct ocelot_vlan native_vlan)
 {
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
-	u32 val = 0;
+	enum ocelot_port_tag_config tag_cfg;
 
 	ocelot_port->native_vlan = native_vlan;
 
@@ -176,16 +176,13 @@ static void ocelot_port_set_native_vlan(struct ocelot *ocelot, int port,
 
 	if (ocelot_port->vlan_aware) {
 		if (native_vlan.valid)
-			/* Tag all frames except when VID == DEFAULT_VLAN */
-			val = REW_TAG_CFG_TAG_CFG(1);
+			tag_cfg = OCELOT_PORT_TAG_NATIVE;
 		else
-			/* Tag all frames */
-			val = REW_TAG_CFG_TAG_CFG(3);
+			tag_cfg = OCELOT_PORT_TAG_TRUNK;
 	} else {
-		/* Port tagging disabled. */
-		val = REW_TAG_CFG_TAG_CFG(0);
+		tag_cfg = OCELOT_PORT_TAG_DISABLED;
 	}
-	ocelot_rmw_gix(ocelot, val,
+	ocelot_rmw_gix(ocelot, REW_TAG_CFG_TAG_CFG(tag_cfg),
 		       REW_TAG_CFG_TAG_CFG_M,
 		       REW_TAG_CFG, port);
 }

include/soc/mscc/ocelot.h

@@ -568,6 +568,17 @@ struct ocelot_vlan {
 	u16 vid;
 };
 
+enum ocelot_port_tag_config {
+	/* all VLANs are egress-untagged */
+	OCELOT_PORT_TAG_DISABLED = 0,
+	/* all VLANs except the native VLAN and VID 0 are egress-tagged */
+	OCELOT_PORT_TAG_NATIVE = 1,
+	/* all VLANs except VID 0 are egress-tagged */
+	OCELOT_PORT_TAG_TRUNK_NO_VID0 = 2,
+	/* all VLANs are egress-tagged */
+	OCELOT_PORT_TAG_TRUNK = 3,
+};
+
 enum ocelot_sb {
 	OCELOT_SB_BUF,
 	OCELOT_SB_REF,