usbcore: add sysfs support to xHCI usb2 hardware LPM

This patch adds sysfs support to xHCI usb2 hardware LPM, so developer can
enable and disable usb2 hardware LPM manually for test purpose.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 15 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 294aa864a60..e647378e9e8 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -142,3 +142,18 @@ Description:
                 such devices.
 Users:
                 usb_modeswitch
+
+What:           /sys/bus/usb/devices/.../power/usb2_hardware_lpm
+Date:           September 2011
+Contact:        Andiry Xu <andiry.xu@amd.com>
+Description:
+                If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device
+                is plugged in to a xHCI host which support link PM, it will
+                perform a LPM test; if the test is passed and host supports
+                USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will
+                be enabled for the device and the USB device directory will
+                contain a file named power/usb2_hardware_lpm.  The file holds
+                a string value (enable or disable) indicating whether or not
+                USB2 hardware LPM is enabled for the device. Developer can
+                write y/Y/1 or n/N/0 to the file to enable/disable the
+                feature.