commit 50fc7b61959af4b95fafce7fe5dd565199e0b61a upstream.

Commit 40f7090bb1b4 ("Input: elan_i2c_smbus - fix corrupted stack")
fixed most of the functions using i2c_smbus_read_block_data() to
allocate a buffer with the maximum block size.  However three
functions were left unchanged:

* In elan_smbus_initialize(), increase the buffer size in the same
  way.
* In elan_smbus_calibrate_result(), the buffer is provided by the
  caller (calibrate_store()), so introduce a bounce buffer.  Also
  name the result buffer size.
* In elan_smbus_get_report(), the buffer is provided by the caller
  but happens to be the right length.  Add a compile-time assertion
  to ensure this remains the case.

Cc: <stable@vger.kernel.org> # 3.19+
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In order to support more projects in the future, we expand the
maximum product_id value form 0xFF to 0xFFFF.

Signed-off by: Duson Lin <dusonlin@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Previously the elan_i2c touchpad driver would simply request the firmware
"/lib/firmware/elan_i2c.bin", which does not work well if there are
multiple such devices in the system.

Let's append the "product ID" (by using the same function as the sysfs
interface for consistency) to the filename.  This results in filenames of
the form "/lib/firmware/elan_i2c_72.0.bin", allowing you to support
multiple elan_i2c touchpads on the same device by simply naming each
device's FW with its corresponding product ID.  This way when you trigger a
fw update the driver will load the correct binary.

Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

In order to support multiple IC types for i2c/smbus protocol, add get ic
type command and use this data when checking firmware page count and
signature address.

Signed-off-by: Duson Lin <dusonlin@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Get pressure format flag from firmware to check if we need to normalize
pressure data before reporting it.

Signed-off-by: Duson Lin <dusonlin@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Fixes: 6696777c6506 ("Input: add driver for Elan I2C/SMbus touchpad")
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

To allow for different firmware sizes let's replace the original size check
with with checking the signature in the firmware data.

Signed-off-by: Duson Lin <dusonlin@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

This driver supports Elan I2C/SMbus touchpads found in some laptops and
also in many Chromebooks.

Signed-off-by: Duson Lin <dusonlin@emc.com.tw>
Reviewed-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>