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Resistive touch screen on A20 micro


frspin

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I am using an A20 micro with an old 10" LCD from Olimex, now discontinued, A13-LCD10TS

All is working without problem but no touch screen.

 

In old Olimex Wheezy image, touch screen was working with tslib.

In new Armbian Jessie image there is no tslib and touch screen is not working.

 

Also using

 

modprobe ft5x_ts

 

as suggested in this forum give an error message

 

modprobe: ERROR: could not insert 'ft5x_ts': Operation not permitted

 

FEX file seem correct and is same as old FEX used with Wheezy

 

What I am missing?

 

Regards

Franco Spinelli

 

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I also have this problem and found the following solution for trusty release 110 which works for me:

 

At start-up, the module a20_tp is loaded (see /etc/modules)

The Olimex "Wheezy" configuration however uses the "sun4i-ts" module for the resistive touch screen of Olinuxino.

 

a20_tp and sun4i-ts are not compatible. If you try to load sun4i-ts via modprobe, you get the information that sun4i-ts cannot get the required IRQ-ressource since this ressource is already occupied by a20_tp.

 

So my solution was to recompile Igors kernel with sun4i-ts as kernel module and not as a loadable module. To do that, change Igor's "compile.sh" from KERNEL_CONFIGURE="no" to KERNEL_CONFIGURE="yes" and change later the module sun4i-ts from <M> to <*>.

 

First success:

After booting, you enter sudo cat /dev/input/event0 and you see strange characters on your screen, if you press your touchscreen.

 

However, this is not sufficient. You have to compile tslib and arrange things, that your new driver is recognized by x11. These procedures are wonderfully described in http://www.dimrobotics.com/2013/06/olinuxino-a13-touchscreen-support-in.html.

 

You will find a similar description on the Olimex site

https://www.olimex.com/wiki/RK3188-SOM#Calibrate_touchscreen

however, the mentioned URL for downloading xf86-input has gone the last days, when I tried to find a solution. Thus, use the download mentioned in dimrobotics.

 

ts_calibrate is working, after you have compiled tslib. The cursor however will go in the inverse horizontal direction. This will be fixed with the xf86-input library.

 

I would be glad, if anyone could find a more simple solution.

In my opinion, the Debian wheezy image was made with a lot of patches to get the Olinuxino working.

On the other hand, Igor made his wonderful images in a more Linux-friendly way as he supports many modules. But note, his main interest seems to focus on headless system without graphical desktop interfaces.

 

Didier

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After your post I commented out a20_tp module from /etc/modules and inserted sun4i-ts in same file

 

After a reboot I was able to work with resistive touch.

 

So problem solved

 

Regards

Franco Spinelli

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