HID: new driver for PicoLCD device

Add basic driver for PicoLCD graphics device.
Initially support keypad with input device and provide support
for debugging communication via events file from debugfs.

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/ABI/testing/sysfs-driver-hid-picolcd b/Documentation/ABI/testing/sysfs-driver-hid-picolcd
new file mode 100644
index 0000000..6fb4f21
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-hid-picolcd
@@ -0,0 +1,17 @@
+What:		/sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/<hid-bus>:<vendor-id>:<product-id>.<num>/operation_mode
+Date:		March 2010
+Contact:	Bruno Prémont <bonbons@linux-vserver.org>
+Description:	Make it possible to switch the PicoLCD device between LCD
+		(firmware) and bootloader (flasher) operation modes.
+
+		Reading: returns list of available modes, the active mode being
+		enclosed in brackets ('[' and ']')
+
+		Writing: causes operation mode switch. Permitted values are
+		the non-active mode names listed when read, optionally followed
+		by a delay value expressed in ms.
+
+		Note: when switching mode the current PicoLCD HID device gets
+		disconnected and reconnects after above delay (default value
+		is 5 seconds though this default should not be relied on).
+