This is a introduction for flashlight chip LM3644

[Scope]
- Two channel for two LEDs
- Two silicon revision
	* LM3644
	* LM3644TT (Douple torch current and flash timeout)


[Hardware Interface]
- I2C
	* For general control
	* Slave address 0x63

- GPIO
	* For enable/disable chip


[Limit]
- Channel couple:
	* Torch/Strobe

- Channel decouple:
	* Enable/Disable
	* Brightness level

- Torch Mode
	* Step current: 1.4 mA (2.8 mA for LM3644TT)
	* Min currnet: 0.977 mA (1.954 mA for LM3644TT)
	* Max current: 179 mA (360 mA for LM3644TT)

- Strobe Mode
	* Step current: 11.725 mA
	* Min currnet: 10.9 mA
	* Max current: 1500 mA
	* Max current for two channel: 1500 mA
	* Min protected timeout: 10 ms (40 ms for LM3644TT)
	* Max protected timeout: 400 ms (1600 ms for LM3644TT)