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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2012-12-18 15:25:46 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-11 16:16:01 -0800
commit8d8479db3dde3ef7a9bc803e565842764fa21a53 (patch)
tree6c4e2b049c675b62be0fd3d65ae606f367dfb56c /drivers/usb/core/usb.h
parentece1d77ed73b335319725f1d5ffa72ca3fa9b05c (diff)
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>
Diffstat (limited to 'drivers/usb/core/usb.h')
-rw-r--r--drivers/usb/core/usb.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 1c528c1bf0be..fb7d8fcb4551 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -38,6 +38,15 @@ extern char *usb_cache_string(struct usb_device *udev, int index);
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,