I have a galaxy note 4 that also have a touchscreen not working, but after I've tried T-Mobile and Samsung to get it fixed, I was turned down because the phone's warranty status expired last November, but Samsung wants me to pay for the repair, well I do not have the money, so I tried my own way trying to solve this problem myself.
After couple of trying, I found Check (TSP/TSK firmware update: *#2663# ) which got my fixed by myself. So I decided to post this to help others that have the same problem, please read this simple step by step guide.
( PLEASE USE YOUR BRAIN AND TAKE CAUTION WHEN DOING THESE, I AM RESPONSIBLE FOR YOUR BROKEN OR BRICKED DEVICE, IF YOU CALL ME OR SEND MSG TO ME THAT YOU DO SOMETHING CRAZY, I WILL LAUGH AT YOU , I AM NOT A DEVELOPERS OR A TECHNICIAN I DO NOT KNOW ANYTHING ABOUT FIXING DEVICE, THIS IS ONLY A TEST AND IT WORKED FOR ME, I HOPE IT WORKED FOR YOU TOO.
1) Open the calling app
2) Dial these secret codes *#2663# and you will have a Firmware version screen pop up
3) Touch to run all all update tabs one by one, if it says (failed to update: FAIL) don't even worry about it
4) When these updates running you will see... (Now updating... Warning! Do not Turn Off) if you turn it off, you will break things.
5) The last you wanna do is Refresh Wifi Version, this will restart your device.
6) After device is restarted, Run only Touch key FW update/Touch key FW update (Kernel Binary) even if they say FAILED:
7) Double tap the back key and it will take you back to calling screen, restart your phone and you should be ready to go.
THANKS FOR READING TO THE END, I HOPE I HOPE I'VE HELPED SOMEONE TODAY., IF THIS WORKED FOR YOU, PLEASE DON'T HESITATE TO SAY THANK YOU
THANK YOU AND GOD BLESS.