I2C Touchscreen fails

      I2C Touchscreen fails

      Hi,

      I'm using a PicoModA9 board under Linux with F&S BSP V2.0.

      Up to now, I used a resistive touchscreen with the standard driver SX8655 and everything went well. The touch events had been arrived in /dev/input/event0.

      Now I switched to a capacitive touchscreen, with the I2C-driver mXT224 from Atmel. I enabled both drivers (SX and mXT) via kernel-"menuconfig" at Device drivers / Input device support / Touchscreens. But after recompilation, there was no additional entry like event1 in dev/input/, so I can not configure tslib for processing the touch events.
      I checked the I2C-bus with i2cdetect and realized, that the mXT224 is connected to I2C-2 at 0x4A:

      # i2cdetect 2
      WARNING! This program can confuse your I2C bus, cause data loss and worse!
      I will probe file /dev/i2c-2.
      I will probe address range 0x03-0x77.
      Continue? [Y/n]

      0 1 2 3 4 5 6 7 8 9 a b c d e f
      00: -- -- -- -- -- -- -- -- -- -- -- -- --
      10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      40: -- -- -- -- -- -- -- -- -- -- 4a -- -- -- -- --
      50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      70: -- -- -- -- -- -- -- --


      but there is no entry like 2-004A in /sys/bus/i2c/devices/.
      Confusing is, that there is a secondary, hidden, entry Use Atmel MXT touch controller in "menuconfig" under System Type / Freescale MXC Implementations / Support F&S Elektronik Systeme GmbH PicoMODA9. Hidden, because this entry is visible only in the case that the appropriate xMT driver entry in touchscreens is disabled. Recompiling the kernel with this alternative option results in a 2-004A entry under /sys/bus/i2c/devices/, but there is still no event1 in dev/input.

      So what should I do?
      Hello,

      it looks like an bug in configuration file. Can you modify the configuration file "(linuxroot)/arch/arm/mach-mx6/Kconfig":
      • remove exclamation mark from the line 958 (depends on !TOUCHSCREEN_ATMEL_MXT)
      • enable atmel touch via menuconfig at System Type / Freescale MXC Implementations / Support F&S Eletronik Systeme GmbH PicoMODA9
      • rebuild the image
      Hope that helps.
      F&S Elektronik Systeme GmbH
      As this is an international forum, please try to post in English.
      Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.