Is there a standard for writing device drivers for microcontrollers?
For ARM Cortex-M processors there is the CMSIS (the Cortex-M Software Interface Standard). CMSIS is intended to provide a standard method for hardware abstraction that can be used by any Cortex-M vendor. TI almost certainly has created some software that provides CMSIS support for their processors, so you should also look for that. The CMSIS documentation and templates are available from cmsis.arm.com