Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (260 commits)
  usb: renesas_usbhs: fixup inconsistent return from usbhs_pkt_push()
  usb/isp1760: Allow to optionally trigger low-level chip reset via GPIOLIB.
  USB: gadget: midi: memory leak in f_midi_bind_config()
  USB: gadget: midi: fix range check in f_midi_out_open()
  QE/FHCI: fixed the CONTROL bug
  usb: renesas_usbhs: tidyup for smatch warnings
  USB: Fix USB Kconfig dependency problem on 85xx/QoirQ platforms
  EHCI: workaround for MosChip controller bug
  usb: gadget: file_storage: fix race on unloading
  USB: ftdi_sio.c: Use ftdi async_icount structure for TIOCMIWAIT, as in other drivers
  USB: ftdi_sio.c:Fill MSR fields of the ftdi async_icount structure
  USB: ftdi_sio.c: Fill LSR fields of the ftdi async_icount structure
  USB: ftdi_sio.c:Fill TX field of the ftdi async_icount structure
  USB: ftdi_sio.c: Fill the RX field of the ftdi async_icount structure
  USB: ftdi_sio.c: Basic icount infrastructure for ftdi_sio
  usb/isp1760: Let OF bindings depend on general CONFIG_OF instead of PPC_OF .
  USB: ftdi_sio: Support TI/Luminary Micro Stellaris BD-ICDI Board
  USB: Fix runtime wakeup on OHCI
  xHCI/USB: Make xHCI driver have a BOS descriptor.
  usb: gadget: add new usb gadget for ACM and mass storage
  ...

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index c9ffa9ced7ee..9d85d96ec6e0 100644
--- a/Documentation/usb/power-management.txt
+++ b/Documentation/usb/power-management.txt
@@ -487,3 +487,29 @@ succeed, it may still remain active and thus cause the system to
 resume as soon as the system suspend is complete.  Or the remote
 wakeup may fail and get lost.  Which outcome occurs depends on timing
 and on the hardware and firmware design.
+
+
+        xHCI hardware link PM
+        ---------------------
+
+xHCI host controller provides hardware link power management to usb2.0
+(xHCI 1.0 feature) and usb3.0 devices which support link PM. By
+enabling hardware LPM, the host can automatically put the device into
+lower power state(L1 for usb2.0 devices, or U1/U2 for usb3.0 devices),
+which state device can enter and resume very quickly.
+
+The user interface for controlling USB2 hardware LPM is located in the
+power/ subdirectory of each USB device's sysfs directory, that is, in
+/sys/bus/usb/devices/.../power/ where "..." is the device's ID. The
+relevant attribute files is usb2_hardware_lpm.
+
+        power/usb2_hardware_lpm
+
+                When a USB2 device which support LPM is plugged to a
+                xHCI host root hub which support software LPM, the
+                host will run a software LPM test for it; if the device
+                enters L1 state and resume successfully and the host
+                supports USB2 hardware LPM, this file will show up and
+                driver will enable hardware LPM for the device. You
+                can write y/Y/1 or n/N/0 to the file to enable/disable
+                USB2 hardware LPM manually. This is for test purpose mainly.