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

Peter Chen
2016-01-18T07:13:09Z

On Fri, Jan 15, 2016 at 12:30:41PM -0500, Alan Stern wrote:
> On Fri, 15 Jan 2016, Philipp Zabel wrote:
>
> > > +- 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).
>
> > > @@ -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