Input: atmel_mxt_ts - Support for touchpad variant

This same driver can be used by atmel based touchscreens and touchpads
(buttonpads). Platform data may specify a device is a touchpad
using the is_tp flag.

This will cause the driver to perform some touchpad specific
initializations, such as:
  * register input device name "Atmel maXTouch Touchpad" instead of
  Touchscreen.
  * register BTN_LEFT & BTN_TOOL_* event types.
  * register axis resolution (as a fixed constant, for now)
  * register BUTTONPAD property
  * process GPIO buttons using reportid T19

Input event GPIO mapping is done by the platform data key_map array.

key_map[x] should contain the KEY or BTN code to send when processing
GPIOx from T19. To specify a GPIO as not an input source, populate
with KEY_RESERVED, or 0.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Platform: x86: chromeos_laptop : Add basic platform data for atmel devices

Add basic platform data to get the current upstream driver working
with the 224s touchpad and 1664s touchscreen.
We will be using NULL config so we will use the settings from the
devices' NVRAMs.

Signed-off-by: Benson Leung <bleung@chromium.org>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>