[Arm-netbook] Testing: GPIO

Jonathan Neuschäfer j.neuschaefer at gmx.net
Sat Mar 3 02:44:48 GMT 2018

On Sat, Mar 03, 2018 at 01:37:15AM +0000, Luke Kenneth Casson Leighton wrote:
> On Fri, Mar 2, 2018 at 10:43 PM, Jonathan Neuschäfer
> <j.neuschaefer at gmx.net> wrote:
> > Hello,
> >
> > I'm not actively working on any of this, but I'm interested in the
> > devicetree side of things.
>  excellent, can you look up the status of A20 and the devicetree fragments?

There has been some work on HDMI on the A10/A20 in October (merged in
4.15): https://www.spinics.net/lists/devicetree/msg198941.html
Reportedly, HDMI works now. I'm not sure what else was/is missing.

About DT fragments: I'm not sure what you mean exactly. Mainline support
devicetree overlays which should do (half of) the job for EOMA68, though.
The tricky part would be figuring out how the same overlay can be used
on base devicetrees for different SoCs, as the exposed busses will have
different names. This may be solved by a future iteration of this
patchset: https://www.spinics.net/lists/kernel/msg2710913.html

The other side of the DT job is the dynamic loading of a devicetree
overlay based on the EEPROM of the connected housing. Mainline Linux
doesn't have something like capemgr[1], AFAIK; But I think this could
also be handled in userspace.
And then there's the question of how the kernel/userspace is supposed to
know on which i2c bus it finds the EOMA68 EEPROM.


[1]: https://elinux.org/Capemgr

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