EBC Exercise 11a Device Trees

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thumb‎ Embedded Linux Class by Mark A. Yoder


The Device Tree (DT), and Device Tree Overlay are a way to describe hardware in a system. This introduction is heavily based on Adafruit's Introduction to the BeagleBone Black Device Tree using Derek Molloy's gpio example.

Compile

beagle$ dtc -O dtb -o DM-GPIO-Test-00A0.dtbo -b 0 -@ DM-GPIO-Test.dts

Compiling the overlay from .dts to .dtbo

Install

beagle$ cp DM-GPIO-Test-00A0.dtbo /lib/firmware
beagle$ echo DM-GPIO-Test > $SLOTS

Verify

Check to be sure it worked

beagle$ cat $SLOTS
 0: 54:PF--- 
 1: 55:PF--- 
 2: 56:PF--- 
 3: 57:PF--- 
 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
 5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
 7: ff:P-O-L Override Board Name,00A0,Override Manuf,DM-GPIO-Test

It's appeard in slot 7. You can remove it with

beagle$ echo -7 > $SLOTS

Be careful though, the current versions appear unstable when removing this way.




thumb‎ Embedded Linux Class by Mark A. Yoder