RIOT defines a low-level CAN device driver interface.
Suppose the MCU (for example, Espressifs ESP32) provides a CAN hardware
implementation that could be used to integrate CAN peripherals into RIOT
if there were a low-level CAN device driver for it. So I thought about
including such a low-level CAN device driver in my ESP32 port.
In accordance with the license terms of Bosch, each implementation of
the CAN protocol and the CAN FD protocol requires a license. From my
point of view, the hardware manufacturer would normally be responsible
for getting a license.
However, Espressif simply states: "Since the selling price of the ESP32
includes no such royalty fee, Espressif hereby disclaims any liability
or obligation regarding the CAN Protocol license. Users of the CAN
Protocol via the ESP32’s CAN peripheral should contact Robert Bosch GmbH
directly for the necessary license."
In this case, should no CAN device driver be available to prevent
license violation by RIOT users? Or should I implement the CAN device
driver and give an important note as it is done by Espressif?
In this case, should no CAN device driver be available to prevent
license violation by RIOT users?
We are not the patent police. Having the software in a repository is not practicing any invention that may be under patent protection. How people use this software is their decision.
(Compare the MP3 patents, which were used as a scarecrow for a while but really never have been in the way of open-source implementations.)
Or should I implement the CAN device
driver and give an important note as it is done by Espressif?
Now that is more interesting.
I am not a patent lawyer, and I have no idea if any of the patents that could potentially be relevant here are still in force in any jurisdiction we care about. I’m not sure if there are people in the RIOT project that know more. We should definitely not be making legal representations that such patents exist, are still in force or are valid in the first place. We don’t even know which jurisdiction a potential user of the software would fall under… (Note that software patents are still formally illegal in Europe [1], this is just implemented in the narrowest way possible [actually, more narrow] by the courts.)
The only valid advice would be to say that there appears to be a heavy patent thicket around CAN and users might need to find out whether their usage of CAN in conjunction with the driver might be covered by any valid, still in-force patents in their jurisdiction. That doesn’t help anyone very much (because we can’t), but at least avoids setting up a trap.
Espressif has deeper pockets and may be more in the need of “cover your ___” phrases. (They may not actually *need* them, but may follow advice by a lawyer that they should include them just in case they might turn out to be useful.)
[Besides the potential patent claims, there may also be a trademark issue around CAN.]