Let's settle on the following scheme for now:

 * struct name: all-caps with Reg suffix: `TIMERReg`
 * extern name: all-caps, like rust static: `TIMER0`
 * getter/setter field names: all-caps for register name: `CR()`, `set_CTCR()`

This would require a most minor refactoring over the code base and is compatible with linter.