The controller driver may be NULL if the controller device is the middle device between platform device and roothub. This middle device may not need a device driver due to all hardware control can be at platform device driver, this platform device is usually a dual-role USB controller device.
The benefit of using this middle device is we can keep both controller device's private data (known as struct usb_hcd) for USB core use, and platform device's private data for platform driver use. Signed-off-by: Peter Chen <peter.c...@nxp.com> --- Changes for v2: - Simplify the code per Alan's suggestion drivers/usb/core/hub.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 4ee2a6a..acba56b 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -4383,6 +4383,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, enum usb_device_speed oldspeed = udev->speed; const char *speed; int devnum = udev->devnum; + const char *driver_name; /* root hub ports have a slightly longer reset period * (from USB 2.0 spec, section 7.1.7.5) @@ -4450,11 +4451,23 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, else speed = usb_speed_string(udev->speed); + /* + * The controller driver may be NULL if the controller device + * is the middle device between platform device and roothub. + * This middle device may not need a device driver due to + * all hardware control can be at platform device driver, this + * platform device is usually a dual-role USB controller device. + */ + if (udev->bus->controller->driver) + driver_name = udev->bus->controller->driver->name; + else + driver_name = udev->bus->sysdev->driver->name; + if (udev->speed < USB_SPEED_SUPER) dev_info(&udev->dev, "%s %s USB device number %d using %s\n", (udev->config) ? "reset" : "new", speed, - devnum, udev->bus->controller->driver->name); + devnum, driver_name); /* Set up TT records, if needed */ if (hdev->tt) { @@ -4586,7 +4599,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, "%s SuperSpeed%s USB device number %d using %s\n", (udev->config) ? "reset" : "new", (udev->speed == USB_SPEED_SUPER_PLUS) ? "Plus" : "", - devnum, udev->bus->controller->driver->name); + devnum, driver_name); } /* cope with hardware quirkiness: -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html