net: dsa: mv88e6xxx: add switch register helpers

The mixed assignments, allocations and registrations in the probe code
make it hard to follow the logic and figure out what is DSA or chip
specific.

Extract the struct dsa_switch related code in a simple
mv88e6xxx_register_switch helper function.

For symmetry in the code, add a mv88e6xxx_unregister_switch function.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx.c

@@ -3690,30 +3690,48 @@ static struct dsa_switch_driver mv88e6xxx_switch_driver = {
 	.port_fdb_dump          = mv88e6xxx_port_fdb_dump,
 };
 
+static int mv88e6xxx_register_switch(struct mv88e6xxx_priv_state *ps,
+				     struct device_node *np)
+{
+	struct device *dev = ps->dev;
+	struct dsa_switch *ds;
+
+	ds = devm_kzalloc(dev, sizeof(*ds), GFP_KERNEL);
+	if (!ds)
+		return -ENOMEM;
+
+	ds->dev = dev;
+	ds->priv = ps;
+	ds->drv = &mv88e6xxx_switch_driver;
+
+	dev_set_drvdata(dev, ds);
+
+	return dsa_register_switch(ds, np);
+}
+
+static void mv88e6xxx_unregister_switch(struct mv88e6xxx_priv_state *ps)
+{
+	dsa_unregister_switch(ps->ds);
+}
+
 static int mv88e6xxx_probe(struct mdio_device *mdiodev)
 {
 	struct device *dev = &mdiodev->dev;
 	struct device_node *np = dev->of_node;
 	struct mv88e6xxx_priv_state *ps;
 	int id, prod_num, rev;
-	struct dsa_switch *ds;
 	u32 eeprom_len;
 	int err;
 
-	ds = devm_kzalloc(dev, sizeof(*ds) + sizeof(*ps), GFP_KERNEL);
-	if (!ds)
+	ps = devm_kzalloc(dev, sizeof(*ps), GFP_KERNEL);
+	if (!ps)
 		return -ENOMEM;
 
-	ps = (struct mv88e6xxx_priv_state *)(ds + 1);
-	ds->priv = ps;
-	ds->dev = dev;
 	ps->dev = dev;
 	ps->bus = mdiodev->bus;
 	ps->sw_addr = mdiodev->addr;
 	mutex_init(&ps->smi_mutex);
 
-	ds->drv = &mv88e6xxx_switch_driver;
-
 	id = mv88e6xxx_reg_read(ps, REG_PORT(0), PORT_SWITCH_ID);
 	if (id < 0)
 		return id;
@@ -3745,9 +3763,7 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
 	if (err)
 		return err;
 
-	dev_set_drvdata(dev, ds);
-
-	err = dsa_register_switch(ds, np);
+	err = mv88e6xxx_register_switch(ps, np);
 	if (err) {
 		mv88e6xxx_mdio_unregister(ps);
 		return err;
@@ -3764,8 +3780,7 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
 	struct dsa_switch *ds = dev_get_drvdata(&mdiodev->dev);
 	struct mv88e6xxx_priv_state *ps = ds_to_priv(ds);
 
-	dsa_unregister_switch(ds);
-
+	mv88e6xxx_unregister_switch(ps);
 	mv88e6xxx_mdio_unregister(ps);
 }