Documentation sysfs-bus-usb: Document all files used by libusb

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 9c8926c5f821..0053ae262a0a 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -263,3 +263,41 @@ Description:
                 Supported values are 0 - 15.
                 More information on how besl values map to microseconds can be found in
                 USB 2.0 ECN Errata for Link Power Management, section 4.10)
+
+What:           /sys/bus/usb/devices/.../devnum
+KernelVersion:  since at least 2.6.18
+Description:
+                Device address on the USB bus.
+
+What:           /sys/bus/usb/devices/.../bConfigurationValue
+KernelVersion:  since at least 2.6.18
+Description:
+                bConfigurationValue of the *active* configuration for the
+                device. Writing 0 or -1 to bConfigurationValue will reset the
+                active configuration (unconfigure the device). Writing
+                another value will change the active configuration.
+
+                Note that some devices, in violation of the USB spec, have a
+                configuration with a value equal to 0. Writing 0 to
+                bConfigurationValue for these devices will install that
+                configuration, rather then unconfigure the device.
+
+                Writing -1 will always unconfigure the device.
+
+What:           /sys/bus/usb/devices/.../busnum
+KernelVersion:  2.6.22
+Description:
+                Bus-number of the USB-bus the device is connected to.
+
+What:           /sys/bus/usb/devices/.../descriptors
+KernelVersion:  2.6.26
+Description:
+                Binary file containing cached descriptors of the device. The
+                binary data consists of the device descriptor followed by the
+                descriptors for each configuration of the device.
+                Note that the wTotalLength of the config descriptors can not
+                be trusted, as the device may have a smaller config descriptor
+                than it advertises. The bLength field of each (sub) descriptor
+                can be trusted, and can be used to seek forward one (sub)
+                descriptor at a time until the next config descriptor is found.
+                All descriptors read from this file are in bus-endian format