The existing implementation which encodes the configuration as a binary
blob in platform data is unsatisfactory since it requires a kernel
recompile for the configuration to be changed, and it doesn't deal well
with firmware changes that move values around on the chip.

Atmel define an ASCII format for the configuration which can be exported
from their tools. This patch implements a parser for that format which
loads the configuration via the firmware loader and sends it to the MXT
chip.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NBenson Leung <bleung@chromium.org>
Acked-by: NYufeng Shen <miletus@chromium.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

By reading the touchscreen configuration from the settings that the
maXTouch chip is actually using, we can remove some platform data.

The matrix size is not used for anything, and results in some rather
confusing code to re-read it because it may change when configuration
is downloaded, so don't print it out.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NBenson Leung <bleung@chromium.org>
Acked-by: NYufeng Shen <miletus@chromium.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

The configuration is stored in NVRAM on the maXTouch chip. When the device
is reset it reports a CRC of the stored configuration values. Therefore it
isn't necessary to send the configuration on each probe - we can check the
CRC matches and avoid a timeconsuming backup/reset cycle.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NBenson Leung <bleung@chromium.org>
Acked-by: NYufeng Shen <miletus@chromium.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

 * The mapping of the GPIO numbers into the T19 status byte varies between
   different maXTouch chips. Some have up to 7 GPIOs. Allowing a keycode array
   of up to 8 items is simpler and more generic. So replace #define with
   configurable number of keys which also allows the removal of is_tp.
 * Rename platform data parameters to include "t19" to prevent confusion with
   T15 key array.
 * Probe aborts early on when pdata is NULL, so no need to check.
 * Move "int i" to beginning of function (mixed declarations and code)
 * Use API calls rather than __set_bit()
 * Remove unused dev variable.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NYufeng Shen <miletus@chromium.org>
Reviewed-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

It is not necessary to download these values to the maXTouch chip on every
probe, since they are stored in NVRAM. It makes life difficult when tuning
the device to keep them in sync with the config array/file, and requires a
new kernel build for minor tweaks.

These parameters only represent a tiny subset of the available
configuration options, tracking all of these options in platform data would
be a endless task. In addition, different versions of maXTouch chips may
have these values in different places or may not even have them at all.

Having these values also makes life more complex for device tree and other
platforms where having to define a static configuration isn't helpful.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NBenson Leung <bleung@chromium.org>
Acked-by: NYufeng Shen <miletus@chromium.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

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: NDaniel Kurtz <djkurtz@chromium.org>
Signed-off-by: NBenson Leung <bleung@chromium.org>
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Tested-by: NOlof Johansson <olof@lixom.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Different board have different requirements/setups so let's be more
flexible.
Signed-off-by: NIiro Valkonen <iiro.valkonen@atmel.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

As there is no common configuration settings that would work in every
situation, remove the fixed config data from driver code and add
config data to platform data.
Signed-off-by: NIiro Valkonen <iiro.valkonen@atmel.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

Change prefixes from qt602240 to mxt to reflect that the driver supports
whole line of mXT touchscreens.
Signed-off-by: NIiro Valkonen <iiro.valkonen@atmel.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

Since the driver will be supporting whole range of Atmels mXT touchscreen
controllers we better rename it to atmel_mxt_ts.
Acked-by: NIiro Valkonen <iiro.valkonen@atmel.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>

The chip's full name is AT42QT602240 or ATMXT224. This is a capacitive
touchscreen supporting 10-contact multitouch and using I2C interface.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Acked-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>