# Development Documentation

This directory contains development notes, implementation decisions, and technical details.

## Contents

### Implementation Notes
- Driver development progress
- Hardware integration challenges
- Performance optimization notes

### Protocol Documentation
- I2C communication protocol
- Register maps
- Command sequences

### Testing Reports
- Hardware validation results
- Performance measurements
- Compatibility testing

## Completed Features

- [x] Project structure and templates
- [x] I2C communication layer with validation
- [x] Fan controller driver implementation
- [x] Basic examples and tests
- [x] Input validation and bounds checking
- [x] Configuration lock race condition fix
- [x] Magic numbers replaced with named constants

## Technical Decisions

Document key technical decisions here as the project evolves:

1. **I2C Locking Strategy**: Using filelock for cross-process locking (following luminex pattern)
2. **Configuration Format**: YAML for human readability
3. **Driver Architecture**: Layered design (I2C -> Driver -> API)
4. **Input Validation**: Comprehensive validation at I2C layer (addresses, registers, block lengths) with clear error messages
5. **Constants Strategy**: All hardware values extracted to constants.py for maintainability and single source of truth
6. **Thread Safety**: Atomic hardware reads for configuration lock to prevent race conditions

## Known Issues

Track known issues and workarounds here.

## Future Enhancements

List potential future features and improvements.
