* @reg_width: size (in bytes) of the IO accesses to the registers
* @reg_offset: offset to apply to the @addr from the start of the registers
* @reg_shift: quantity to shift the register offsets by
* @reg_width: size (in bytes) of the IO accesses to the registers
* @reg_offset: offset to apply to the @addr from the start of the registers
* @reg_shift: quantity to shift the register offsets by