This macro was invented by Mattias Nilsson for the usecase where you want to set a sequence of bits inside a n-bit word, while leaving the head and tail of the sequence all zeroes. For example:
#include <linux/bitops.h> u16 mask = BITS(4, 12); Yields a mask like this: 0001111111110000 This patch moves the construct out of the MFD PRCMU driver and make it available for common use, after noticing in a review or two that it would be useful for others. Cc: Akinobu Mita <m...@miraclelinux.com> Signed-off-by: Linus Walleij <linus.wall...@linaro.org> --- drivers/mfd/dbx500-prcmu-regs.h | 2 -- include/linux/bitops.h | 1 + 2 files changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/mfd/dbx500-prcmu-regs.h b/drivers/mfd/dbx500-prcmu-regs.h index 4f6f0fa..906e75e 100644 --- a/drivers/mfd/dbx500-prcmu-regs.h +++ b/drivers/mfd/dbx500-prcmu-regs.h @@ -13,8 +13,6 @@ #ifndef __DB8500_PRCMU_REGS_H #define __DB8500_PRCMU_REGS_H -#define BITS(_start, _end) ((BIT(_end) - BIT(_start)) + BIT(_end)) - #define PRCM_ACLK_MGT (0x004) #define PRCM_SVAMMCSPCLK_MGT (0x008) #define PRCM_SIAMMDSPCLK_MGT (0x00C) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index a3b6b82..1f9d78b 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -6,6 +6,7 @@ #define BIT(nr) (1UL << (nr)) #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) +#define BITS(_start, _end) ((BIT(_end) - BIT(_start)) + BIT(_end)) #define BITS_PER_BYTE 8 #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) #endif -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/