C Macros for field addressing

macb.h

#define MACB_RMII_OFFSET			0
#define MACB_RMII_SIZE				1
#define GEM_RGMII_OFFSET			0 /* GEM gigabit mode */
#define GEM_RGMII_SIZE				1
#define MACB_CLKEN_OFFSET			1
#define MACB_CLKEN_SIZE	1

<...>

/* Bit manipulation macros */
#define MACB_BIT(name)					\
	(1 << MACB_##name##_OFFSET)
#define MACB_BF(name,value)				\
	(((value) & ((1 << MACB_##name##_SIZE) - 1))	\
	 << MACB_##name##_OFFSET)
#define MACB_BFEXT(name,value)\
	(((value) >> MACB_##name##_OFFSET)		\
	 & ((1 << MACB_##name##_SIZE) - 1))
#define MACB_BFINS(name,value,old)			\
	(((old) & ~(((1 << MACB_##name##_SIZE) - 1)	\
		    << MACB_##name##_OFFSET))		\
| MACB_BF(name,value))