Hey everyone,

at LPC next week in Lisboa, there will be a BoF run by me which I want
to point out. Quoting the official description[1]:


"New hardware with modern I2C address conflicts"

For some time now, special camera setups exist having features which are
challenging for I2C address layouts as we know them in Linux: a) a
high-speed serial link which can embed I2C communication (e.g. GMSL or
FPD-Link III) and b) the ability to reprogram the client addresses of
the I2C devices on the camera.

The use case for these cameras is to run multiple of them in parallel,
and not just a single one. To be easily pluggable, they don't have a way
to configure the I2C addresses they need. They use initially all the
same I2C addresses and rely on software to reprogram them and sort out
that problem.

The really tricky thing is now that they are connected to the same
serial high speed link. As a result, all the clients with initially
equal addresses sit (more or less, depending on the link) on the same
I2C bus as well and need to be carefully reprogrammed one-by-one to a
unique address.

The camera setup above is the primary example we are facing right now.
Some early implementations for GMSL and FPD-Link exist with different
approaches to map the I2C topology. However, there might be other
hardware facing very similar problems. We definitely want to have you in
the room.

An introductory talk gives a few more details of current
implementations, and explains the current problems in abstracting all
this. From there on, we hope to have gathered enough highly interested
people for discussion, opinions, and brainstorming. The goal is, of
course, to enhance the I2C core to provide reasonable support for such
scenarios which will be beneficial for all users like these high speed


The BoF takes place 11 Sep 2019, 10:45 in the Ametista-room-I.

If you face similar problems, know other HW behaving like this, or are
simply interested, you are very welcome to join the BoF. Or contact me
beforehand at the conference.

Hope to see you there!

Happy hacking,


[1] https://linuxplumbersconf.org/event/4/contributions/542/

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