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usb: core: hub: controller driver name may be NULL

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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.chen@nxp.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Chen 2017-07-19 14:40:53 +08:00 committed by Greg Kroah-Hartman
parent d9241ff2f2
commit 1bb90cf046
1 changed files with 15 additions and 2 deletions
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17
drivers/usb/core/hub.c
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@ -4342,6 +4342,7 @@ 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)
@ -4409,11 +4410,23 @@ 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) {
@ -4545,7 +4558,7 @@ 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: