Access MMIO without going through HAL or drivers

Verification

• I searched for similar issues and found none was relevant.

Introduce the issue

I have noticed that some code accesses memory-mapped I/O (MMIO) without going through Hardware Abstraction Layer (HAL) or drivers. This type of access may have several drawbacks, including poor portability and reusability.

I would like to open this issue to investigate why some MMIO access does not follow the conventional path through HAL or drivers. Are there specific scenarios where non-conventional MMIO access is preferred or a must (e.g. because, for example, SDK does not provide the necessary API)? Is it possible to fix the code by accessing MMIO conventionally (i.e. through HAL/drivers)?

Code snippets with MMIO access that does not go through HAL or drivers:

1. NRF_TIMER2->CC[0] in https://github.com/InfiniTimeOrg/InfiniTime/blob/d968bcb1f3afd2364558e41013dbd2d6d5c286aa/src/main.cpp#L345
2. https://github.com/InfiniTimeOrg/InfiniTime/blob/d968bcb1f3afd2364558e41013dbd2d6d5c286aa/src/components/firmwarevalidator/FirmwareValidator.cpp#L8-L11
   On the contrary, FirmwareValidator::Validate() uses driver API to write to validBitAdress: https://github.com/InfiniTimeOrg/InfiniTime/blob/d968bcb1f3afd2364558e41013dbd2d6d5c286aa/src/components/firmwarevalidator/FirmwareValidator.cpp#L15

Preferred solution

No response

Version

No response

Start with the cited MMIO access in src/main.cpp and src/components/firmwarevalidator/FirmwareValidator.cpp, including FirmwareValidator::Validate() and validBitAdress. Compare these sites with the available HAL or driver paths and determine whether each direct access has a necessary exception or can be replaced conventionally; completion requires a documented decision for both examples.