USB: Export URB statistics for powertop

powertop currently tracks interrupts generated by uhci, ehci, and ohci,
but it has no way of telling which USB device to blame USB bus activity on.
This patch exports the number of URBs that are submitted for a given device.
Cat the file 'urbnum' in /sys/bus/usb/devices/.../

Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index e02590297d31..b04afd06e502 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -169,6 +169,16 @@ show_quirks(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);
 
+static ssize_t
+show_urbnum(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct usb_device *udev;
+
+        udev = to_usb_device(dev);
+        return sprintf(buf, "%d\n", atomic_read(&udev->urbnum));
+}
+static DEVICE_ATTR(urbnum, S_IRUGO, show_urbnum, NULL);
+
 
 #if defined(CONFIG_USB_PERSIST) || defined(CONFIG_USB_SUSPEND)
 static const char power_group[] = "power";
@@ -458,6 +468,7 @@ static struct attribute *dev_attrs[] = {
         &dev_attr_bConfigurationValue.attr,
         &dev_attr_bmAttributes.attr,
         &dev_attr_bMaxPower.attr,
+        &dev_attr_urbnum.attr,
         /* device attributes */
         &dev_attr_idVendor.attr,
         &dev_attr_idProduct.attr,