For BSP 1.x to automatically apply the calibration settings upon boot proceed as follows:
root@colibri_t20:~# mkdir /etc/X11/xorg.conf.d
root@colibri_t20:~# xinput_calibrator
Calibrating EVDEV driver for "wm97xx touchscreen" id=6
current calibration values (from XInput): min_x=3991, max_x=58 and min_y=3932, max_y=351
Doing dynamic recalibration:
Setting new calibration data: 3999, 74, 4016, 296
--> Making the calibration permanent <--
copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf'
Section "InputClass"
Identifier "calibration"
MatchProduct "wm97xx touchscreen"
Option "Calibration" "3999 74 4016 296"
EndSection
Now just create the 99-calibration.conf file according to the xinput_calibrator output above:
root@colibri_t20:~# vi /etc/X11/xorg.conf.d/99-calibration.conf
:i
Section "InputClass"
Identifier "calibration"
MatchProduct "wm97xx touchscreen"
Option "Calibration" "3999 74 4016 296"
EndSection
~
:wq
root@colibri_t20:~#
To automatically apply the calibration settings upon boot one can also proceed as follows:
System - Preferences - Startup Applications
Add
Name: Touch Calibration
Command: xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 3995 88 3861 304
Comment: Apply touch calibration
As command one can just use the xinput command as output by the xinput_calibrator application. Alternatively if you require more than one xinput command for proper calibration (e.g. due to swapped axes) you can create a script /usr/bin/touch.sh and use this as above command:
#!/bin/sh
export DISPLAY=:0
xinput set-int-prop "wm97xx touchscreen" "Evdev Axes Swap" 8 1
xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 3957 148 197 3295
xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 137 4130 3147 179
Note (BSP 1.x): Somehow due to swapped axes the calibration needs to be run twice in order to get the desired result.
root@colibri_t20:~# export DISPLAY=:0
root@colibri_t20:~# xinput_calibrator
Calibrating EVDEV driver for "wm97xx touchscreen" id=6
current calibration values (from XInput): min_x=3995, max_x=88 and min_y=3861, max_y=304
Doing dynamic recalibration:
Swapping X and Y axis...
Setting new calibration data: 3957, 148, 197, 3295
If you have the 'xinput' tool installed, a simple way is to create a script that starts with your X session, containing the following command(s):
xinput set-int-prop "wm97xx touchscreen" "Evdev Axes Swap" 8 1
xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 3957 148 197 3295
If you have evdev version 2.3.0 or higher, there are 2 more ways: the traditional way (xorg.conf) and the new way (udev rule):
xorg.conf: edit /etc/X11/xorg.conf and add in the 'Section "InputDevice"' of your device:
Option "Calibration" "3957 148 197 3295"
Option "SwapAxes" "1" # unless it was already set to 1
udev rule: create the file '/etc/udev/rules.d/99_touchscreen.rules' with:
ACTION!="add|change", GOTO="xorg_touchscreen_end"
KERNEL!="event*", GOTO="xorg_touchscreen_end"
ATTRS{product}!="wm97xx touchscreen", GOTO="xorg_touchscreen_end"
ENV{x11_options.calibration}="3957 148 197 3295"
ENV{x11_options.swapxy}="1"
LABEL="xorg_touchscreen_end"
root@colibri_t20:~# export DISPLAY=:0
root@colibri_t20:~# xinput_calibrator
Calibrating EVDEV driver for "wm97xx touchscreen" id=6
current calibration values (from XInput): min_x=350, max_x=3900 and min_y=320, max_y=3750
Doing dynamic recalibration:
Setting new calibration data: 3995, 88, 3861, 304
If you have the 'xinput' tool installed, a simple way is to create a script that starts with your X session, containing the following command(s):
xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 3995 88 3861 304
If you have evdev version 2.3.0 or higher, there are 2 more ways: the traditional way (xorg.conf) and the new way (udev rule):
xorg.conf: edit /etc/X11/xorg.conf and add in the 'Section "InputDevice"' of your device:
Option "Calibration" "3995 88 3861 304"
udev rule: create the file '/etc/udev/rules.d/99_touchscreen.rules' with:
ACTION!="add|change", GOTO="xorg_touchscreen_end"
KERNEL!="event*", GOTO="xorg_touchscreen_end"
ATTRS{product}!="wm97xx touchscreen", GOTO="xorg_touchscreen_end"
ENV{x11_options.calibration}="3995 88 3861 304"
LABEL="xorg_touchscreen_end"
Please note that instead of PWM A the Tellurium uses PWM C aka PWFM2 for back light control requiring a custom kernel to be built with MECS_TELLURIUM being defined (see arch/arm/mach-tegra/board-colibri_t20-panel.c).
root@colibri_t20:~# export DISPLAY=:0
root@colibri_t20:~# xinput_calibrator
Calibrating EVDEV driver for "wm97xx touchscreen" id=6
current calibration values (from XInput): min_x=350, max_x=3900 and min_
y=320, max_y=3750
Doing dynamic recalibration:
Setting new calibration data: 107, 3959, 3939, 137
If you have the 'xinput' tool installed, a simple way is to create a script that starts with your X session, containing the following command(s):
xinput set-int-prop "wm97xx touchscreen" "Evdev Axis Calibration" 32 107 3959 3939 137
If you have evdev version 2.3.0 or higher, there are 2 more ways: the traditional way (xorg.conf) and the new way (udev rule):
xorg.conf: edit /etc/X11/xorg.conf and add in the 'Section "InputDevice"' of your device:
Option "Calibration" "107 3959 3939 137"
udev rule: create the file '/etc/udev/rules.d/99_touchscreen.rules' with:
ACTION!="add|change", GOTO="xorg_touchscreen_end"
KERNEL!="event*", GOTO="xorg_touchscreen_end"
ATTRS{product}!="wm97xx touchscreen", GOTO="xorg_touchscreen_end"
ENV{x11_options.calibration}="107 3959 3939 137"
LABEL="xorg_touchscreen_end"
[ 6.865817] wm97xx-ts 0-0:WM9711,WM9712,WM9715: detected a wm9712 codec
[ 6.880561] input: wm97xx touchscreen as /devices/platform/tegra-ac97/0-0:WM9711,WM9712,WM9715/input/input2
The Colibri VF61 uses the Wolfson WM9712 AC97 audio codec for resistive touch support. The driver has several kernel parameters which can be tuned:
| Parameter |
Data type |
Description |
| rpu |
int |
Set internal pull up resistor for pen detect. |
| pil |
int |
Set current used for pressure measurement. |
| pressure |
int |
Set threshold for pressure measurement. |
| delay |
int |
Set adc sample delay. |
| abs_x |
array of int |
Touchscreen absolute X min, max, fuzz |
| abs_y |
array of int |
Touchscreen absolute X min, max, fuzz |
| abs_p |
array of int |
Touchscreen absolute Pressure min, max, fuzz |
The source file in drivers/input/touchscreen/wm9712.c has some more hints to the exact meaning of the values.
The WM9712 driver module is built-in, to set a module parameter the kernel command line needs to be altered. Use the module name wm97xx-ts as prefix so set a parameter:
setenv defargs wm97xx-ts.pil=1
