libopencm3
A free/libre/open-source firmware library for various ARM Cortex-M3 microcontrollers.
LM3S
Here is a list of all modules:
[detail level 12]
 LM3SLibraries for TI Stellaris LM3S series
 General Purpose I/OLM3S General Purpose I/O
 RCC ControllerLM3S RCC Controller
 LM3S DefinesDefined Constants and Types for the LM3S series
 General Purpose I/O DefinesDefined Constants and Types for the LM3S General Purpose I/O
 System ControlDefined Constants and Types for the LM3S System Control
 RCC DefinesDefined Constants and Types for the LM3S Reset and Clock Control