[Arm-netbook] devicetree and testing

Richard Wilbur richard.wilbur at gmail.com
Wed Apr 18 13:46:55 BST 2018

On Apr 17, 2018, at 16:17, Luke Kenneth Casson Leighton <lkcl at lkcl.net>

On Tue, Apr 17, 2018 at 11:12 PM, Richard Wilbur
<richard.wilbur at gmail.com> wrote:

In my estimation the tasks that can be completed relatively quickly are 1
and 3 as they don't require convincing anyone else of the importance of the
goal or merit of the implementation.

it is slightly more complex (3 that is) because a library and
associated linux kernel device-driver has to also be written that
reads from the I2C EEPROM (to be added to both u-boot and the linux
kernel), in order to use the devicetree fragment merging... overlay!
that's what it's called.

it is *not* going to be okay to just blop in one devicetree file for
eoma68-a20-with-microdesktop, one devicetree file for
eoma68-rk3288-with-microdesktop, one devicetree file for
eoma68-a20-with-laptop-housing, one devicetree file for
eoma68-rk3288-with-laptop-housing etc. etc.

preventing that kind of insane O(N * M) devicetree proliferation and
reducing it down to O(N + M)  *IS* the entire point of the EOMA68

I agree wholeheartedly with the modular mix and match overlay fragment
design but saw the software support for it in what I had labelled as
priority 4.  Whereas I understood priority 3 to entail creating the
devicetree fragments for the EOMA hardware that already exists.

1.  Hack together some tests under 3.4.104 that we can run on the extant


2.  Work on getting extant A20 drivers mainlined in the linux kernel.

3.  Create devicetree [fragments] for DS113 v2.7.4 and v2.7.5, … (all
extant versions

of DS113 and microdesktop case).

4.  Work on getting devicetree with [fragment] add/remove overlay support
mainlined in

the linux kernel (and u-boot?).

Let me restate without relying only on numbers to identify the tasks:
We can create the tests to run on 3.4.104 kernel (priority 1) and the
devicetree overlays or fragments for each version of the processor card and
microdesktop case (priority 3) without buy in from anyone else.

Getting the A20 drivers mainlined in the linux kernel (priority 2) and
devicetree fragment overlay add/remove support in the linux kernel and
u-boot (priority 4) will require continued collaboration with those who
maintain the linux kernel and u-boot.  Others have already been working on
this effort for several years.

More information about the arm-netbook mailing list