usb: core: add support for USB_REQ_SET_ISOCH_DELAY
USB SS and SSP hubs provide wHubDelay values on their hub descriptor
which we should inform the USB Device about.
The USB Specification 3.0 explains, on section 9.4.11, how to
calculate the value and how to issue the request. Note that a
USB_REQ_SET_ISOCH_DELAY is valid on all device states (Default,
Address, Configured), we just *chose* to issue it from Address state
right after successfully fetching the USB Device Descriptor.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 2bee08d..149cc74 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -40,6 +40,7 @@ extern int usb_remove_device(struct usb_device *udev);
extern int usb_get_device_descriptor(struct usb_device *dev,
unsigned int size);
+extern int usb_set_isoch_delay(struct usb_device *dev);
extern int usb_get_bos_descriptor(struct usb_device *dev);
extern void usb_release_bos_descriptor(struct usb_device *dev);
extern char *usb_cache_string(struct usb_device *udev, int index);