[fedora-arm] beaglebone black GPIO questions

[Peter Robinson]

On Thu, Jan 22, 2015 at 4:48 PM, Bram Van Steenlandt <bram at diomedia.be> wrote:
> Hi,
>
> I installed fedora 21 on a beaglebone black, I was amazed how easy this was
> and how well most things work.

Good news.

> 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 [1] 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.

> 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
expansion board.

Depending on what device you're trying to configure you might just be
able to do it with a basic script.

Peter

[1] http://koji.fedoraproject.org/koji/buildinfo?buildID=604938