net: ag71xx: use devm for of_mdiobus_register

Allows removing ag71xx_mdio_remove.

Removed ag.mii_bus variable. Local one can be used with devm. Easier to
reason about as mii_bus is only used here now. Also shrinks the struct
slightly.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://patch.msgid.link/20240813170516.7301-3-rosenp@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/atheros/ag71xx.c

@@ -380,7 +380,6 @@ struct ag71xx {
 	int mac_idx;
 
 	struct reset_control *mdio_reset;
-	struct mii_bus *mii_bus;
 	struct clk *clk_mdio;
 	struct clk *clk_eth;
 };
@@ -697,7 +696,6 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
 	int err;
 
 	np = dev->of_node;
-	ag->mii_bus = NULL;
 
 	ag->clk_mdio = devm_clk_get_enabled(dev, "mdio");
 	if (IS_ERR(ag->clk_mdio)) {
@@ -731,22 +729,14 @@ static int ag71xx_mdio_probe(struct ag71xx *ag)
 	}
 
 	mnp = of_get_child_by_name(np, "mdio");
-	err = of_mdiobus_register(mii_bus, mnp);
+	err = devm_of_mdiobus_register(dev, mii_bus, mnp);
 	of_node_put(mnp);
 	if (err)
 		return err;
 
-	ag->mii_bus = mii_bus;
-
 	return 0;
 }
 
-static void ag71xx_mdio_remove(struct ag71xx *ag)
-{
-	if (ag->mii_bus)
-		mdiobus_unregister(ag->mii_bus);
-}
-
 static void ag71xx_hw_stop(struct ag71xx *ag)
 {
 	/* disable all interrupts and stop the rx/tx engine */
@@ -1932,14 +1922,14 @@ static int ag71xx_probe(struct platform_device *pdev)
 	err = ag71xx_phylink_setup(ag);
 	if (err) {
 		netif_err(ag, probe, ndev, "failed to setup phylink (%d)\n", err);
-		goto err_mdio_remove;
+		return err;
 	}
 
 	err = register_netdev(ndev);
 	if (err) {
 		netif_err(ag, probe, ndev, "unable to register net device\n");
 		platform_set_drvdata(pdev, NULL);
-		goto err_mdio_remove;
+		return err;
 	}
 
 	netif_info(ag, probe, ndev, "Atheros AG71xx at 0x%08lx, irq %d, mode:%s\n",
@@ -1947,23 +1937,16 @@ static int ag71xx_probe(struct platform_device *pdev)
 		   phy_modes(ag->phy_if_mode));
 
 	return 0;
-
-err_mdio_remove:
-	ag71xx_mdio_remove(ag);
-	return err;
 }
 
 static void ag71xx_remove(struct platform_device *pdev)
 {
 	struct net_device *ndev = platform_get_drvdata(pdev);
-	struct ag71xx *ag;
 
 	if (!ndev)
 		return;
 
-	ag = netdev_priv(ndev);
 	unregister_netdev(ndev);
-	ag71xx_mdio_remove(ag);
 	platform_set_drvdata(pdev, NULL);
 }