[Ltib] [Fwd: Touch screen problem for Phytec LPC3250 development board.]

[Stuart Hughes]

FYI, maybe this can help others.  Thanks Dmitry

--- Begin Message --- Subject: Touch screen problem for Phytec LPC3250 development board. Date: Tue, 4 Aug 2009 09:52:44 +0300

    Hi, Stuart

I working with Phytec development board.
My  application (GUI, GTK with DirectFB) working with touch screen.

I want to tell what problems I encountered and how to solve them.

 Touch screen driver "LPC32xx Touchscreen" in Linux this is device event0.

1. Touch screen driver not working if started as module, built-in it's working good.

2. event0 need to move from /dev/event0 to /dev/input/event0, because DirectFB search it in this directory.

3. Need make enviroment variales for ts_calibration util.
    export TSLIB_TSDEVICE=/dev/input/event0

    export TSLIB_CALIBFILE=/etc/pointercal

4. DirectFB not working correct with "LPC32xx Touchscreen" driver, because use raw data - not calibrated values.
    To solve this problem:
    1. Need extract /opt/ltib/pkgs/DirectFB-1.1.0.tar.gz to your directory of ltib ../ltib/rpm/BUILD
    2. Copy file tsc_correct.c (see attachment) to ltib/rpm/BUILD/DirectFB-1.1.0/inputdrivers/linux_input
    3. Edit source code of linux_input.c file. (see below comment "Dima")
    4. Rebuild the file system of target linux (cd ltib && ./ltib )

How it's work.

After screen calibration with ts_calibration util will be created file with name that contain in TSLIB_CALIBFILE enviroment variable.

In run time of  linux_input_EventThread function tsc_get_calib_file() get the values from the TSLIB_CALIBFILE.

After each driver event tsc_correct_ts_data( &devt ); function do calculation for screen values.



--------------- linux_input.c file. Fragment ----------------------


/* Dima */
#include "tsc_correct.c"
/*  */
/*
 * Input thread reading from device.
 * Generates events on incoming data.
 */
static void*
linux_input_EventThread( DirectThread *thread, void *driver_data )
{
     LinuxInputData    *data = "" driver_data;
     int                readlen, status, i;
     struct input_event levt[64];
     fd_set             set;
     struct touchpad_fsm_state fsm_state;

     /* Query min/max coordinates. */
     if (data->touchpad) {
          touchpad_fsm_init( &fsm_state );

          struct input_absinfo absinfo;

          ioctl( data->fd, EVIOCGABS(ABS_X), &absinfo );
          fsm_state.x.min = absinfo.minimum;
          fsm_state.x.max = absinfo.maximum;

          ioctl( data->fd, EVIOCGABS(ABS_Y), &absinfo );
          fsm_state.y.min = absinfo.minimum;
          fsm_state.y.max = absinfo.maximum;
     }

      /* Dima */
      tsc_get_calib_file();
      /*  */

     while (1)
      {
          FD_ZERO( &set );
          FD_SET( data->fd, &set );

          if (data->touchpad && timeout_is_set( &fsm_state.timeout )) {
              struct timeval time;
              gettimeofday( &time, NULL );

              if (!timeout_passed( &fsm_state.timeout, &time )) {
                  struct timeval timeout = fsm_state.timeout;
                  timeout_sub( &timeout, &time );
                  status = select( data->fd + 1, &set, NULL, NULL, &timeout );
              } else {
                  status = 0;
              }
          }
          else {
              status = select( data->fd + 1, &set, NULL, NULL, NULL );
          }

          if (status < 0 && errno != EINTR)
              break;

          direct_thread_testcancel( thread );

          if (status < 0)
              continue;

          /* timeout? */
          if (status == 0) {
              DFBInputEvent devt;

              if (data->touchpad && touchpad_fsm( &fsm_state, NULL, &devt ) > 0)
                  dfb_input_dispatch( data->device, &devt );

              continue;
          }

          readlen = read( data->fd, levt, sizeof(levt) );

          if (readlen < 0 && errno != EINTR)
              break;

          direct_thread_testcancel( thread );

          if (readlen <= 0)
              continue;

          for (i=0; i<readlen / sizeof(levt[0]); i++) {
              DFBInputEvent devt;

              if (data->touchpad) {
                  status = touchpad_fsm( &fsm_state, &levt[i], &devt );
                  if (status < 0) {
                      /* Not handled. Try the direct approach. */
                      if (!translate_event( &levt[i], &devt ))
                          continue;
                  }
                  else if (status == 0) {
                      /* Handled but no further processing is necessary. */
                      continue;
                  }
              }
              else {
                  if (!translate_event( &levt[i], &devt ))
                      continue;
              }

              if (devt.type == DIET_AXISMOTION && (devt.flags & DIEF_AXISREL)) {
                  switch (devt.axis) {
                      case DIAI_X:
                          data->dx += devt.axisrel;
                          continue;

                      case DIAI_Y:
                          data->dy += devt.axisrel;
                          continue;

                      default:
                          break;
                  }
              }

              flush_xy( data );

                    
              /* Dima */
              tsc_correct_ts_data( &devt );
             /*  */
                    

              dfb_input_dispatch( data->device, &devt );

              if (data->has_leds && (devt.locks != data->locks)) {
                  set_led( data, LED_SCROLLL, devt.locks & DILS_SCROLL );
                  set_led( data, LED_NUML, devt.locks & DILS_NUM );
                  set_led( data, LED_CAPSL, devt.locks & DILS_CAPS );
                  data->locks = devt.locks;
              }
          }

          flush_xy( data );
     }

     if (status <= 0)
          D_PERROR ("linux_input thread died\n");

     return NULL;
}

--
Best Regards,
Dmitry.
Embedded Development Engineer
Israel.
Mobile:
  052 6 144 338
  0507 63 53 10

tsc_correct.c
Description: Binary data

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