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

Alan Stern stern at rowland.harvard.edu
Mon Jan 18 08:39:06 PST 2016


On Mon, 18 Jan 2016, Peter Chen wrote:

> > > 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.

It already _has_ an .of_node field, in its embedded struct device.

> 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.

I don't know what you mean.  struct usb_device _does_ contain an 
embedded struct device.  It doesn't matter the structures are created 
dynamically, statically, or any other way; this field is part of the 
structure definition.

Suppose udev is a pointer to struct usb_device.  Then udev->dev is a
struct device and udev->dev.of_node is a pointer to struct device_node.  
You don't need to add a new udev->of_node field; just use
udev->dev.of_node instead.

Alan Stern




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