STM32 Libraries not GPL compatible

[mlyle]

Need to add appropriate exception to our license to allow linking with STM32 libraries. Need to make best-effort to clear with existing contributors. (But should be OK). Need to be careful going forward-- it'll be difficult to bring in any third-party GPL code.

[mlyle]

The issue is this clause:

1. This software, including modifications and/or derivative works of this software, must execute solely and exclusively on microcontroller or microprocessor devices manufactured by or for STMicroelectronics.

which is an incompatible restriction on use.

The GPLv3 says:

A “Standard Interface” means an interface that either is an official standard defined by a recognized standards body, or, in the case of interfaces specified for a particular programming language, one that is widely used among developers working in that language.

The “System Libraries” of an executable work include anything, other than the work as a whole, that (a) is included in the normal form of packaging a Major Component, but which is not part of that Major Component, and (b) serves only to enable use of the work with that Major Component, or to implement a Standard Interface for which an implementation is available to the public in source code form. A “Major Component”, in this context, means a major essential component (kernel, window system, and so on) of the specific operating system (if any) on which the executable work runs, or a compiler used to produce the work, or an object code interpreter used to run it.

The ST libraries probably do not qualify under the system library exception as written.

But I think this is the best path-- to clarify that we consider the STM32 libraries and CMSIS components included within the source as "System Libraries" under the terms of the GPL, in our licensing document and contributing.md file.

[mlyle]

http://debian.2.n7.nabble.com/MCD-ST-Liberty-SW-License-Agreement-td3526097.html

[tracernz]

There is a 3rd party GPL ST lib out there.

[mlyle]

If it's this thing -- https://github.com/MaJerle/stm32fxxx_hal_libraries --- it's ostensibly under the GPL but contains the ST code :/