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MityARM-335x Development Kit touch screen
Added by Jesse Johnston about 11 years ago
I am having trouble using the touch screen on the MityARM-335x Development Kit wit the mityarm-linux-v3.2 branch of the kernel repository.
I built the boot loader using instructions from : http://support.criticallink.com/redmine/projects/armc8-platforms/wiki/Das_U-Boot_Port. Then I built the kernel using the AM335XPSP_04.06.00.02 branch and following the instructions on : http://support.criticallink.com/redmine/projects/armc8-platforms/wiki/Linux_Kernel. When I loaded this on the MityARM-335x Development Kit everything seemed to run fine.
Next I build the kernel from the mityarm-linux-v3.2 branch. When I load this on the dev kit, the touch screen does not work. It looks like the device and driver were loaded correctly, but I dont seem to be getting any touchscreen events. For instance, when I run ts_test and touch the screen, I get no output.
Replies (6)
RE: MityARM-335x Development Kit touch screen - Added by Jonathan Cormier about 11 years ago
Jesse,
This is a known issue with the current 3.2 kernel. Noted here: http://support.criticallink.com/redmine/projects/armc8-platforms/wiki/Cl_v32_AM335XPSP_#Known-Issues
I was unable to determine why the touch events were coming in during my initial testing. Is there any specific reason for changing to the 3.2 kernel for your application?
I'm not familiar with how the touch screen works. If anyone else could chime in. Could this line be related to the touch screen, it has the letters lcd in it? If so then maybe we aren't giving it power...
_regulator_get: deviceless supply vdd_vlcd not found, using dummy regulator
RE: MityARM-335x Development Kit touch screen - Added by Jonathan Cormier about 11 years ago
Jesse,
It also looks like when we switched from 3.1 to 3.2, we switched from the touchscreen driver we wrote to the one that TI added in 3.2. If you could switch back to ours and report whether it starts working that would be a good first step.
In the .config file enable CONFIG_TOUCHSCREEN_TI_ADC and disable CONFIG_TOUCHSCREEN_TI_TSCADC.
RE: MityARM-335x Development Kit touch screen - Added by Jesse Johnston about 11 years ago
When I diff the config file between the two branches ( git difftool mityarm-linux-v3.2 AM335XPSP_04.06.00.02 -- arch/arm/configs/mityarm-335x-devkit_defconfig ), I don't see any changes to CONFIG_TOUCHSCREEN_TI_ADC or CONFIG_TOUCHSCREEN_TI_TSCADC. So I don't think that's the issue.
RE: MityARM-335x Development Kit touch screen - Added by Jonathan Cormier about 11 years ago
Jesse,
I agree that doesn't look like it would be the problem.
RE: MityARM-335x Development Kit touch screen - Added by Jonathan Cormier about 11 years ago
Jesse,
I just pushed an update to the 3.2 branch.
Upon further investigation it was found that the 3.2 change included some behind the scenes changes to how ti was initializing the touchscreen. A new omap_hwmod interface was added that was responsible for setting up a devices clocks. The am335xevm code had been updated to use it. I updated our tsc code to match theirs.
http://support.criticallink.com/gitweb/?p=linux-mityarm-335x.git;a=commitdiff;h=8f0c75dcd09fe8c1bdd412119cf17c0127dcfb5d
http://support.criticallink.com/gitweb/?p=linux-mityarm-335x.git;a=commitdiff;h=e3794df7258c9b4a1c3cd78963be1119de6d393b
Please let me know if this works for you.
RE: MityARM-335x Development Kit touch screen - Added by Jesse Johnston about 11 years ago
Thanks Jonathan.
I just pulled down the latest from the mityarm-linux-v3.2 branch and the touchscreen is working.
