License used by Arduino

As we are also starting to publish open source hardware on the net, it is required to know about the license which is used by Arduino and other open source projects.
So i found the list of available open source license http://opensource.org/licenses

The famous Arduino project uses
Code license: GNU General Public License v2
Content license: Creative Commons 3.0 BY-SA

So to publish hardware content, we have adopted GNU General Public License v2