op 22-01-15 18:01, Peter Robinson schreef:
On Thu, Jan 22, 2015 at 4:48 PM, Bram Van Steenlandt
> I installed fedora 21 on a beaglebone black, I was amazed how easy this was
> and how well most things work.
> I can't seem to get GPIO working, first dtc needed a patch for the -@
> option, after I finally seem to got that working
> I now find I have no
> /sys/devices/bone_capemgr* directory.
The capemgr bits are a custom kernel from BBone that never made it
upstream. The ability to do DeviceTree overlays only landed mainline
in 3.19 so you would need at 3.19rc5  or later Fedora kernel. I've
got as far as testing that the kernel boots on the BBB with the kernel
with overlays enabled but not had enough time to test them.
Ok, then I would like
to avoid them, I'm hoping to also run freebsd in
the future and I don't think they they will have the device tree overlay
> Can anyone here confirm the status of GPIO (and other cape features) ? does
> it require a custom kernel ? Am I missing someting ?
GPIO works, it doesn't need capes to do that. Basically overlays are
just a means of automating the configuration of all features on a
particular addon card whether you call it a cape, a hat or an
Depending on what device you're trying to configure you might just be
able to do it with a basic script.
output works by doing:
echo 48 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio48/direction
echo 1 > /sys/class/gpio/gpio48/value
however, for the input I need to enable the pull up resistor ( I think).
cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pins | grep "pin 46"
pin 46 (44e108b8.0) 00000008 pinctrl-single
I need to change this (00000008) but can't seem to figure out how.
The board I'm trying to use has a dts file saying:
0x030 0x37 /* INPUT MODE7 pullup */
Is there an equivalent to achieve this without a dts file ?
All information I found seems to point either to the device tree overlay
all I have here is a subdirectory board which is empty.