On 03/06/2017 02:19 PM, Alison Schofield wrote:
On Mon, Mar 06, 2017 at 08:04:21AM +0000, Jonathan Cameron wrote:
On 5 March 2017 23:52:04 GMT+00:00, Alison Schofield <amsfield22@xxxxxxxxx> wrote:
Hi IIO Community,
I attended the Linux Foundation's Embedded Linux and OpenIoT Summit in
Portland, Oregon recently.
I've appended a few excerpts from my blog write-up below and the full
text of my report is available here:
https://outreachyiio.blogspot.com/2017/03/embedded-linux-conference-openiot.html
alisons
8< ......... snipped a bunch to focus on the ev3 sensor ...............
IIO Community Hindsight: David Lechner
When I met David displaying his ev3 devices at the technical showcase,
I
didn't know of him from the IIO community. David has some drivers he
wants upstreamed to IIO. Potential Outreachy projects? I'm fuzzy on
this. Can we add support for sensors that basically have no datasheet,
but that David has reverse engineered?
Sure we can. Lots of drivers in the wider kernel are reverse engineered. A few in IIO may well have been.
Hmm would take a slightly brave outreach y candidate perhaps.
I'm going to try to pull David in here, so he can fill in & correct me.
I think David has kernel drivers he has written (loadable kernel
modules - not user space drivers) that could be pushed upstream.
(still could take significant bravery I guess)
David, Am I getting anything right here? And, are there any destined for IIO?
Mostly right. ;-)
When I started hacking on LEGO Mindstorms, I didn't know about the IIO
subsystem (or about Linux drivers in general). So, I create my own
subsystem that is very similar to IIO. The TL;DR; is that these drivers
need to be converted to the IIO subsystem. It is a bit more involved
than just "cleaning it up".
If you want to learn more about what I have done so far you can find the
code at
<https://github.com/ev3dev/lego-linux-drivers/tree/master/sensors> and
some documentation at <http://www.ev3dev.org/docs/sensors/>.
There are a couple of things needed that I don't think exist in the IIO
subsystem yet though (I asked Matt during his talk and he didn't know of
any).
These sensors have "modes". When you change the mode of a sensor, it
changes the data being received. For example, there is a color sensor
that can measure ambient light, reflected light or color. But it can't
do all of these at the same time. You have to set the mode first and
interpret the data received based on the mode. I have a hunch that if I
dug into it some more, I could figure out a way to do this using the
existing iio code though.
Some of these sensors also have "commands". Commands can do things like
trigger a sensor calibration. This is the part I am not so sure about.
And, FYI, most of these sensors do have some sort of technical
documentation from the manufacturer.
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