Letux Kernel


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Table of Content

How to control Devices from user space (command line)


This page lists the most important devices and drivers that are specific to this board. And how they can be accessed from user space.


see Video


see Sound

Headset out / AUX in

The audio amplifier is controlled by (state=0: AUX IN, state=1: AUX OUT)

echo $state >/sys/devices/virtual/gpio/gpio55/value

If enabled, you can't use the AUX IN


power (state=0: off, state=1: on)

echo $state >/sys/devices/virtual/gpio/gpio57/value


see GPS

AUX and Power button

Button Status

The AUX button status can be read through

cat /sys/devices/virtual/gpio/gpio7/value  # 0=AUX pressed

The AUX button is available through a TPS GPIO button driver as an input key event. The power button is available through the TPS driver as an input key event.

?? /sys/bus/platform/devices/twl4030_pwrbutton


LEDs are switched through the TCA6507 driver ($value = 0: on, 1: off, 2..255: blinking/pulsing)

    echo $value >/sys/class/leds/tca6507.0/brightness  # AUX - red
    echo $value >/sys/class/leds/tca6507.1/brightness  # AUX - green
    echo $value >/sys/class/leds/tca6507.3/brightness  # POWER - red
    echo $value >/sys/class/leds/tca6507.4/brightness  # POWER - green


Depending on the exact version of the board there may be I2C devices (besides the touch screen controller).

You should install http://packages.debian.org/de/lenny/i2c-tools resp. http://www.lm-sensors.org/wiki/I2CTools


There should be the following commands

  • i2cdetect
  • i2cdump
  • i2cget
  • i2cset

ADCs of the TPS65950

are available through /dev/twl4030-madc and the madc driver. See e.g. http://www.jumpnowtek.com/index.php?option=com_content&view=article&id=79&Itemid=91

ADC0: BATID (default: 0V) ADC1: BATTEMP (default: 1.8V) ADC2: ADC2IN (default: 0V) ADC7: MICSENSE (no headset / short / headset)