Re: [PATCH net-next] net: dsa: mt7530: support OF-based registration of switch MDIO bus

[Arınç ÜNAL]

On 8.01.2024 14:00, Vladimir Oltean wrote:
> On Mon, Jan 08, 2024 at 01:22:18PM +0300, Arınç ÜNAL wrote:
> > > > diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> > > > index 391c4dbdff42..39d7e7ad7154 100644
> > > > --- a/drivers/net/dsa/mt7530.c
> > > > +++ b/drivers/net/dsa/mt7530.c
> > > > @@ -2153,17 +2153,25 @@ mt7530_free_irq(struct mt7530_priv *priv)
> > > >    static int
> > > >    mt7530_setup_mdio(struct mt7530_priv *priv)
> > > >    {
> > > > +	struct device_node *mnp, *np = priv->dev->of_node;
> > > >    	struct dsa_switch *ds = priv->ds;
> > > >    	struct device *dev = priv->dev;
> > > >    	struct mii_bus *bus;
> > > >    	static int idx;
> > > > -	int ret;
> > > > +	int ret = 0;
> > > > +
> > > > +	mnp = of_get_child_by_name(np, "mdio");
> > > > +
> > > > +	if (mnp && !of_device_is_available(mnp))
> > > > +		goto out;
> > >
> > > nit: I think it would easier on the eyes to simply
> > >
> > > 		return 0;
>
> Actually "return 0" leaks "mnp". An of_node_put() is needed.

I realised that I also miss these:

- run of_node_put(mnp) if bus = devm_mdiobus_alloc(dev) fails
- don't run mt7530_free_mdio_irq if MDIO bus is described on OF

Please let me know if this addresses everything:

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 391c4dbdff42..cf2ff7680c15 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2146,24 +2146,40 @@ mt7530_free_irq_common(struct mt7530_priv *priv)
 static void
 mt7530_free_irq(struct mt7530_priv *priv)
 {
-	mt7530_free_mdio_irq(priv);
+	struct device_node *mnp, *np = priv->dev->of_node;
+
+	mnp = of_get_child_by_name(np, "mdio");
+	if (!mnp)
+		mt7530_free_mdio_irq(priv);
+	of_node_put(mnp);
+
 	mt7530_free_irq_common(priv);
 }
 
 static int
 mt7530_setup_mdio(struct mt7530_priv *priv)
 {
+	struct device_node *mnp, *np = priv->dev->of_node;
 	struct dsa_switch *ds = priv->ds;
 	struct device *dev = priv->dev;
 	struct mii_bus *bus;
 	static int idx;
-	int ret;
+	int ret = 0;
+
+	mnp = of_get_child_by_name(np, "mdio");
+
+	if (mnp && !of_device_is_available(mnp))
+		goto out;
 
 	bus = devm_mdiobus_alloc(dev);
-	if (!bus)
-		return -ENOMEM;
+	if (!bus) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (!mnp)
+		ds->user_mii_bus = bus;
 
-	ds->user_mii_bus = bus;
 	bus->priv = priv;
 	bus->name = KBUILD_MODNAME "-mii";
 	snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d", idx++);
@@ -2174,16 +2190,18 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
 	bus->parent = dev;
 	bus->phy_mask = ~ds->phys_mii_mask;
 
-	if (priv->irq)
+	if (priv->irq && !mnp)
 		mt7530_setup_mdio_irq(priv);
 
-	ret = devm_mdiobus_register(dev, bus);
+	ret = devm_of_mdiobus_register(dev, bus, mnp);
 	if (ret) {
 		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
-		if (priv->irq)
+		if (priv->irq && !mnp)
 			mt7530_free_mdio_irq(priv);
 	}
 
+out:
+	of_node_put(mnp);
 	return ret;
 }
 

Arınç