}
 #endif /* CONFIG_NET_DSA_HWMON */
 
-static char *mv88e6xxx_lookup_name(struct device *host_dev, int sw_addr,
+static char *mv88e6xxx_lookup_name(struct mii_bus *bus, int sw_addr,
                                   const struct mv88e6xxx_switch_id *table,
                                   unsigned int num)
 {
-       struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
        int i, ret;
 
        if (!bus)
        /* Look up only the product number */
        for (i = 0; i < num; ++i) {
                if (table[i].id == (ret & PORT_SWITCH_ID_PROD_NUM_MASK)) {
-                       dev_warn(host_dev, "unknown revision %d, using base switch 0x%x\n",
+                       dev_warn(&bus->dev,
+                                "unknown revision %d, using base switch 0x%x\n",
                                 ret & PORT_SWITCH_ID_REV_MASK,
                                 ret & PORT_SWITCH_ID_PROD_NUM_MASK);
                        return table[i].name;
                          unsigned int num)
 {
        struct mv88e6xxx_priv_state *ps;
+       struct mii_bus *bus = dsa_host_dev_to_mii_bus(host_dev);
        char *name;
 
-       name = mv88e6xxx_lookup_name(host_dev, sw_addr, table, num);
+       if (!bus)
+               return NULL;
+
+       name = mv88e6xxx_lookup_name(bus, sw_addr, table, num);
        if (name) {
                ps = devm_kzalloc(dsa_dev, sizeof(*ps), GFP_KERNEL);
                if (!ps)