Device tree binding: can not make work my touch device
If the GPIO pin is used by another device, you will get such device busy error. Check whether any other device is using it. 

You can try either of the following :

Do not load the other driver that uses the GPIO that you are currently trying to use in your touchscreen driver by either not including the other driver at all or remove the other driver related information from device tree (dtsi)
or 
Use an alternate GPIO pin for your touchscreen that is not used for other purposes while you use the touchscreen.