[tslib] Questions regard whether tslib can work with driverless touchscreen

[JC Yang]

Hi, I’m new to tslib and have questions.
I’ve got a touchscreen connected via serial port and no known kernel drivers for it.
>From the tslib introduction and tutorial, it seems that it support any devices generate Linux input events and multitouch events, but you also stated “in case the operating system doesn't provide driver support.”  Doesn’t it suggest it support driverless touchscreens(at least for a list of known work models, I guess?).
But all related information about “How To connect a serial port touchscreen without driver/How to use tslib as userspace driver daemon for your TS” are vague at best(not even google help). I know I can read the source code and get the conclusion but I’m not permitted to take long time to do it.
So I do my experiments, simply invoke a properly configured(hopefully understand your tutorial correctly) ts_calibrate with TSLIB_TSDEVICE=/dev/ttyConnectedToTouch does not work at all. It says “Selected device is not a Linux input event device”
 
Anything wrong with my approach? Or maybe the fact is that tslib does not implement any userspace daemon to interpret RealRaw touch signals for any models? Is the real meaning of “drivers” within “in case the operating system doesn't provide driver support.” same as any calibration and filtering tools from vendors(but tslib do rely on vendor provided /in kernel tree/userspace daemon to present a /dev/input/eventX)? Is calibration/filtering the real meaning of “access touchscreen devices” in your introduction?
 
Thanks and hope that in anyway this subject should be better documented rather than rely on user investigations.