The irq_to_gpio() is old, most platforms use GENERIC_GPIO framework
and don't support this API anymore.

The i.MX6q sabrelite platform equips an egalax touchscreen controller,
and this platform already transfered to GENERIC_GPIO framework, to
support this driver, we use a more generic way to get gpio.

Add a return value checking for waking up the controller in the probe
function, this guarantee only a workable device can pass init.

[dmitry.torokhov@gmail.com: Make driver depend on CONFIG_OF as it is
 now required.]

Acked-by Zhang Jiejing <jiejing.zhang@freescale.com>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Hui Wang <jason77.wang@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

During the device tree integration of the various LPC32xx drivers,
we agreed on using non-wildcard "compatible" strings. This change
switches lpc32xx_ts touchscreen driver to use "nxp,lpc3220-tsc".

Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

This change implements device tree support for the LPC32xx SoC's touchscreen
controller.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>