All drivers in this fold are stm32f429 oem driver, which base stm32 libirary.

ioctol cmd:
	All driver should use the same rule to generate cmd,
	#define xx_MAJOR
	#define xx_IOCTL_MAGIC 'x'
	#define GENERATE_CMD(__MAGIC__, __MAJOR__, __CMD__) \
		((0x3<<30) | (__MAJOR__<<16) | (__MAGIC__<<8) | __CMD__)

	#define CMD0	GENERATE_CMD(xx_IOCTL_MAGIC, xx_MAJOR, 0)
	#define CMD1	GENERATE_CMD(xx_IOCTL_MAGIC, xx_MAJOR, 1)
	...				...
	#define CMDn	GENERATE_CMD(xx_IOCTL_MAGIC, xx_MAJOR, n)


interrupt:
	Interrupt group is NVIC_PRIORITYGROUP_4, 4 bits for pre-emption priority, 0 bits for subpriority. (set in platform module).
	
	i2c1,i2c2,i2c3 event interrupt pre-emption priority is 2, subpriority is 0.
	i2c1,i2c2,i2c3 error interrupt pre-emption priority is 15, subpriority is 0.

	gpio exti interrupt pre-emption priority is 3.