[PATCH v3 1/1] USB: core: let USB device know device node

On Fri, Jan 15, 2016 at 12:30:41PM -0500, Alan Stern wrote:

On Fri, 15 Jan 2016, Philipp Zabel wrote:

quoted

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+- reg: the port number which this device is connecting to.

Should it be noted here that the port number range is 1-255?

Actually the range is 1 - 31 (defined by USB_MAXCHILDREN set in 
include/uapi/linux/usb/ch11.h).

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@@ -502,11 +503,14 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
 	dev->connect_time = jiffies;
 	dev->active_duration = -jiffies;
 #endif
-	if (root_hub)	/* Root hub always ok [and always wired] */
+	if (root_hub) {	/* Root hub always ok [and always wired] */
 		dev->authorized = 1;
-	else {
+		dev->of_node = bus->controller->of_node;

Why can't the root_hub reuse dev->dev.of_node?

Indeed, there's no need to add an .of_node field to struct usb_device, 
since the embedded struct device already contains an .of_node field.

No, the usb_device needs the .of_node field.

The devices belong to platform bus contains device node.
The devices (usb device) belong to USB bus which are created
dynamically do not contain device node.

-- 

Best Regards,
Peter Chen