If you are looking for more information about tenure and academic freedom, the American Association of University Professors has a very comprehensive page about how students and professors have academic freedom: AAUP.
Tierney and Lanford (2014) tierney-lanford-2014 have a nice review of the origins and present state of academic freedom in numerous areas of the world.
Trower (2009) trower-2009 speaks about inequality in tenure practice in that minority faculty earn tenure at lower rates than white faculty.
Someone in class tonight mentioned that it would be nice to add more emphasis on service in order to earn tenure instead of mostly a focus on research. I could see that greater use of advocacy work could allow faculty to better advocate for minority faculty and students. Could this be a controversial topic that faculty could utilize their academic freedom to pursue with research, teaching, and service in order to create more equality?