How to control Devices from user space (command line)

Introduction

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

Display

Touch Screen

is mapped to

/dev/input/touchscreen

pen down status can be read through

cat /sys/devices/virtual/gpio/gpio160/value

LCD

can be selected by adding "omapdss.def_disp=lcd" to the boot args. This is done by "setenv defaultdisplay lcd" in our boot.scr.

To disable/enable (power down/up) the LCD (state=0: off, state=1: on)

echo "$state" >/sys/devices/omapdss/display2/enabled

DVI - on Beagleboard only!

can be selected by adding "omapdss.def_disp=dvi" to the boot args

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

echo $state >/sys/devices/virtual/gpio/gpio170/value

Video out (can't use headset mic)

can be selected by adding "omapdss.def_disp=venc" to the boot args

To disable/enable (power down/up) the LCD (state=0: off, state=1: on) in the DSS system:

echo "$state" >/sys/devices/omapdss/display1/enabled

The video out amplifier is controlled by (state=0: off, state=1: on)

echo $state >/sys/devices/virtual/gpio/gpio23/value

Headset out / AUX in

The video amplifier is controlley 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

Backlight

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

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

GPS

power (state=0: off, state=1: on) - you may have to switch on/off/on to reset the GPS chip

echo $state >/sys/devices/virtual/gpio/gpio145/value

device file (use 9600 baud)

cat /dev/ttyS1

if the external antenna is active can be determined through

cat /sys/devices/virtual/gpio/gpio144/value  # 1=ext. ant.

AUX and Power button

button status can be read through

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

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

LEDs are switched through the TCA6507 driver

**** FIXME **** echo $state >/sys/devices/virtual/gpio/gpio70/value # AUX - red echo $state >/sys/devices/virtual/gpio/gpio71/value # AUX - green echo $state >/sys/devices/virtual/gpio/gpio78/value # POWER - red echo $state >/sys/devices/virtual/gpio/gpio79/value # POWER - green

I2C

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

Commands

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)