So I was following another one of Derek Molloy’s videos on using the BBB, this time on GPIO’s:
Beaglebone: GPIO Programming on ARM Embedded Linux
Around 8:00, he goes into a directory called omap_mux in the sys/kernel/debug directory, but I don’t see it in my BBB. I’ve Googled around and found that a lot of people have this problem, but couldn’t find a real solution.
As far as I understand this directory is supposed to have all the pins for GPIO. Is that correct? How can I get around this to access GPIO? Thanks for any help with this! 
FYI, when I run uname -a I get the following output:
Linux beaglebone 3.8.13 #1 SMP Wed Sep 4 09:09:32 CEST 2013 armv7l GNU/Linux
I have the same problem, and i use the same version of angstrom. But no have the solution.
I have the same problem, and i use the same version of angstrom. But no have the solution.
So I was following another one of Derek Molloy’s videos on using the BBB, this time on GPIO’s:
Beaglebone: GPIO Programming on ARM Embedded Linux
Around 8:00, he goes into a directory called omap_mux in the sys/kernel/debug directory, but I don’t see it in my BBB. I’ve Googled around and found that a lot of people have this problem, but couldn’t find a real solution.
mount -t debugfs none /sys/kernel/debug
Regards,
John
The BBB uses 3.8 or higher version kernel. It does not have any omap_mux, but it has Device Tree Overlays instead.
For me all of the capable pins were in GPIO mode (mode 7), however you can change their modes by passing arguments to “/sys/devices/bone_capemgr*/slots” For example the
echo cape-bone-iio > /sys/devices/bone_capemgr.*/slots will enable the “cape analog input mode”.
You can disable cape modes with echo -N >/sys/devices/bone_capemgr*/slots N is the number of a particular mode. You can see them, if you cat out the slots file.
If you programming with C (very good decision) you should use fprintf(FILE_pointer_to_slots, “cape-bone-iio”) with the popper context of course (like opening the file for reading etc…).
For more info: http://elinux.org/BeagleBone_and_the_3.8_Kernel#Cape_Manager_and_Device_Tree_Overlays
I see your question is old, but when I searched this problem I also read this thread… for nothing. So maybe it will helpful to others as well.