CC-BY-SA 3.0 license compatibility with LGPL & GPL license.

[bperrybap]

It is my understanding that CC-BY-SA 3.0 is not compatible with LGPL & GPL code and that
CC-BY-SA 4.0 was created to address this.
Overall, it looks very tricky to comply with CC-BY-SA licensing given that there is so much LGPL and GPL code that will likely be linked into a given Arduino project that might also use this library.
Would you consider modifying your license to CC-BY-SA 4.0 or LGPL or GPL ?
If the goal is to ensure that the source always remains open source then GPL v3 will ensure that.

Here is more on the subject.
In terms of mixing s/w with different licenses,
there appears to be license compatibility issues when trying to mix CC BY-SA code
with LGPL or GPL code.

From these links:
https://creativecommons.org/compatiblelicenses/
https://wiki.creativecommons.org/wiki/ShareAlike_compatibility:_GPLv3
https://wiki.creativecommons.org/wiki/ShareAlike_compatibility_process_and_criteria

It appears that CC BY-SA 3.0 is only compatible with itself and cannot be used/linked
with LGPL or GPL code.
CC BY-SA 4.0 was created to allow merging & linking CC BY-SA code with LGPL/GPL code and in particular GPLv3.
However, if BY-SA 4.0 code is linked with LGPL or GPL code, the overall work is
licensed based on the other code license (LGPL or GPL).
i.e. if you compile and link CC BY-SA 4.0 code with LGPL 2.1 the entire project
(including the CC BY-SA 4.0 code) will be licensed as LGPL 2.1
i.e. the CC BY-SA 4.0 code converts to LGPL 2.1 for that project.
Likewise when linked against GPLv3, it becomes GPLv3 code.
Essentially it looks like CC BY-SA code is incompatible with LGPL & GPL code and the only way to use CC BY-SA code with LGPL/GPL code is to use CC BY-SA 4.0 and to use the one way convert clause to convert it to LGPL/GPL for the specific project at which point the code in that specific project is no longer CC BY-SA 4.0 and so any improvements/derivatives made to that code by someone else within that project are now LGPL/GPL and cannot go back into the original CC BY-SA 4.0 version of the code.

The person is free to contribute the changes back to the CC BY-SA 4.0 code parent instead to put the changes back into the CC BY-SA code, but it is not a requirement.

Overall, it looks like CC BY-SA licensing is very difficult to work with for s/w, and in particular for s/w that is linking against LGPL and/or GPL code.

In other words, it looks to me like CC BY-SA is a license that was intended for standalone "blobs" that do not incorporate other components, and in particular components that have a different license.
In the case of s/w library, that isn't the case.

[cfobel]

Based on the points raised by @bperrybap, @todbot would you consider re-licensing under a more common software license, such as LGPL or BSD?

[todbot]

Apologies @bperrybap for not getting back to you on this. And thank you @cfobel for poking the issue. I've updated the license to be GPLv3.