Can't calibrate capacitive touchscreen with Qt5 and EGLFS

RazZziel

I'm trying to make the following Zytronic BTC_ZXY100-U-OFF-32-A USB touchscreen with Qt5/EGLFS on a Raspberry Pi 2 with Raspian and libts-0.0-0:armhf 1.0-12:

Bus 001 Device 035: ID 14c8:0005 Zytronic 
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x14c8 Zytronic
  idProduct          0x0005 
  bcdDevice            1.00
  iManufacturer           1 Zytronic Displays Limited
  iProduct                2 Zytronic Touchscreen Controller
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           34
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         3 Human Interface Device
      bInterfaceSubClass      0 No Subclass
      bInterfaceProtocol      0 None
      iInterface              0 
        HID Device Descriptor:
          bLength                 9
          bDescriptorType        33
          bcdHID               1.01
          bCountryCode            0 Not supported
          bNumDescriptors         1
          bDescriptorType        34 Report
          wDescriptorLength     219
         Report Descriptors: 
           ** UNAVAILABLE **
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               8
Device Status:     0x0002
  (Bus Powered)
  Remote Wakeup Enabled

which is detected as:

/dev/input/event0
/dev/input/mouse0
/dev/input/by-path/platform-3f980000.usb-usb-0:1.2:1.0-event
/dev/input/by-id/usb-Zytronic_Displays_Limited_Zytronic_Touchscreen_Controller-event-if00

When I run my application, the mouse is detected and works almost perfectly: it's miscalibrated, and I don't know how to calibrate it.

I forced QT_QPA_EGLFS_TSLIB=1 (with TSLIB_TSDEVICE=/dev/input/event0) to use the tslib input plugin instead of evdev, in an attempt to calibrate with ts_calibrate but the app now doesn't recognize touchs at all. Indeed, ts_calibrate doesn't recognice touchs at all, and neither does ts_print. When I use module_raw ucb1x00 instead of module_raw input, ts_print starts recognizing activity when I slide my finger on the touchscreen, but ts_calibrate still refuses to work.

If it helps, this is the output of evtest when touching, sliding and raising my finger: https://clbin.com/dGBLI. It looks pretty standard to me:

type 1 (EV_KEY), code 330 (BTN_TOUCH), value 1
type 3 (EV_ABS), code 53 (ABS_MT_POSITION_X), value 3623
type 3 (EV_ABS), code 54 (ABS_MT_POSITION_Y), value 1298
type 1 (EV_KEY), code 330 (BTN_TOUCH), value 0

My questions:

How do I calibrate a touchscreen works almost perfectly with Qt5's evdev plugin?
How do I make this touchscreen work with tslib?

Zola

Take a look here.