usb/core: consider link speed while looking at bMaxPower
The USB 2.0 specification says that bMaxPower is the maximum power
consumption expressed in 2 mA units and the USB 3.0 specification says
that it is expressed in 8 mA units.
This patch adds a helper function usb_get_max_power() which computes the
value based on config & usb_device's speed value. The the device descriptor
dump computes the value on its own.
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 1c528c1..fb7d8fcb 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -38,6 +38,15 @@
extern int usb_set_configuration(struct usb_device *dev, int configuration);
extern int usb_choose_configuration(struct usb_device *udev);
+static inline unsigned usb_get_max_power(struct usb_device *udev,
+ struct usb_host_config *c)
+{
+ /* SuperSpeed power is in 8 mA units; others are in 2 mA units */
+ unsigned mul = (udev->speed == USB_SPEED_SUPER ? 8 : 2);
+
+ return c->desc.bMaxPower * mul;
+}
+
extern void usb_kick_khubd(struct usb_device *dev);
extern int usb_match_one_id_intf(struct usb_device *dev,
struct usb_host_interface *intf,