[PATCH net-next v2 08/10] net: dsa: Add support for platform data

On 01/13/2017 06:11 AM, Andrew Lunn wrote:

quoted

 static int _dsa_register_switch(struct dsa_switch *ds, struct device *dev)
 {
+	struct dsa_chip_data *pdata = dev->platform_data;
 	struct device_node *np = dev->of_node;
 	struct dsa_switch_tree *dst;
 	struct device_node *ports;
 	u32 tree, index;
 	int i, err;
 
-	err = dsa_parse_member_dn(np, &tree, &index);
-	if (err)
-		return err;
+	if (np) {
+		err = dsa_parse_member_dn(np, &tree, &index);
+		if (err)
+			return err;
 
-	ports = dsa_get_ports(ds, np);
-	if (IS_ERR(ports))
-		return PTR_ERR(ports);
+		ports = dsa_get_ports(ds, np);
+		if (IS_ERR(ports))
+			return PTR_ERR(ports);
 
-	err = dsa_parse_ports_dn(ports, ds);
-	if (err)
-		return err;
+		err = dsa_parse_ports_dn(ports, ds);
+		if (err)
+			return err;
+	} else {
+		err = dsa_parse_member(pdata, &tree, &index);

Hello Andrew,

Hi Florian

Maybe it is hiding, but i don't see anywhere you check that pdata !=
NULL.

You are right, there is not such a check, it should probably be added
early on.

At least for x86 platforms, i don't expect we are booting using
platform data like ARM systems used to do. I think it is more likely a
glue module will be loaded. It looks up the MDIO bus and appends a
platform data to an MDIO device. The switch driver then needs to load
and use the platform data. But if things happen in a different order,
it could be the switch driver probes before the glue driver, meaning
pdata is NULL.

That's very valid, I will fix this, thanks!

Do we even want to return -EPROBE_DEFERED?

I was trying to exercise that code path a little bit, but could not
quite make sense of what I was seeing, let me try again with more tracing.
-- 
Florian