[Buildroot] Howto use capes for the Beaglebone Black?

[Buildroot] Howto use capes for the Beaglebone Black?

[Ralph Koettlitz]

I missed the development of device tree and my last information was that I
should use dtb file in /lib/firmware, but the kernel from the last stable
version 08.2014 for Beaglebone Black doesn't has a cape manager. like the
starter images from beagleboard.org. Looking at the repositories of Robert
C. Nelson gives me the idea newer kernels have something builtin.

I have a can cape and 7" lcd with touch screen and want to use them. What
must I do to activate them? I'm using the last stable version with the tI
kernel 3.12.10. Maybe I have to use a kernel from RobertCNelson?
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[Buildroot] Howto use capes for the Beaglebone Black?

[Anders Darander]

On 5 November 2014 12:32, Ralph Koettlitz <ralph.koettlitz@gmail.com> wrote:

> I missed the development of device tree and my last information was that I
> should use dtb file in /lib/firmware, but the kernel from the last stable
> version 08.2014 for Beaglebone Black doesn't has a cape manager. like the
> starter images from beagleboard.org. Looking at the repositories of
> Robert C. Nelson gives me the idea newer kernels have something builtin.
>

Yes, the TI-kernels lacks cape-manager support. The reason is that adding
dynamic reconfiguration of the DTB to the kernel, has required quite a few
re-writes to get something that's going to be accepted upstream.

The work on getting the transactional device tree support is on-going.
There was a presentation on that at ELC-E this fall. (The slides are
available at
http://events.linuxfoundation.org/sites/events/files/slides/dynamic-dt-elce14.pdf
).


> I have a can cape and 7" lcd with touch screen and want to use them. What
> must I do to activate them? I'm using the last stable version with the tI
> kernel 3.12.10. Maybe I have to use a kernel from RobertCNelson?
>

If you want to use cape-manager, this is likely the route you'll have to
take (I'm assuming that  his kernels has cape-manager support).

I would likely just patch the the dts-file to add support for the capes,
and thus get the drivers to find their bindings anyway. That would means
that you'd loose the HW-reconfigurability, though, if you're always running
with a limited set of capes, that should/could be just fine.

Cheers,
Anders

-- 
Anders Darander
EPO guidelines 1978: "If the contribution to the known art resides
solely in a computer program then the subject matter is not
patentable in whatever manner it may be presented in the claims."
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