Re: [Outreachy kernel] [PATCH 2/2] media: zoran: replace bit shifts by BIT() macro

From: Julia Lawall
Date: Thu Apr 08 2021 - 17:15:28 EST




On Fri, 9 Apr 2021, Mitali Borkar wrote:

> Added #include <linux/bitops.h> and replaced bit shifts by BIT() macro.
> This BIT() macro from linux/bitops.h is used to define ZR36057_VFESPFR_* bitmasks.
> Use of macro is better and neater. It maintains consistency.
> Reported by checkpatch.
>
> Signed-off-by: Mitali Borkar <mitaliborkar810@xxxxxxxxx>
> ---
> drivers/staging/media/zoran/zr36057.h | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/media/zoran/zr36057.h b/drivers/staging/media/zoran/zr36057.h
> index a2a75fd9f535..93075459f910 100644
> --- a/drivers/staging/media/zoran/zr36057.h
> +++ b/drivers/staging/media/zoran/zr36057.h
> @@ -8,6 +8,8 @@
> #ifndef _ZR36057_H_
> #define _ZR36057_H_
>
> +#include <linux/bitops.h>
> +
> /* Zoran ZR36057 registers */
>
> #define ZR36057_VFEHCR 0x000 /* Video Front End, Horizontal Configuration Register */
> @@ -31,12 +33,12 @@
> #define ZR36057_VFESPFR_VER_DCM 8
> #define ZR36057_VFESPFR_DISP_MODE 6
> #define ZR36057_VFESPFR_YUV422 (0 << 3)
> -#define ZR36057_VFESPFR_RGB888 (1 << 3)
> +#define ZR36057_VFESPFR_RGB888 BIT(3)

Uniformity is generally considered to be more important than using BIT.
Having only a few constants defined using BIT is a bit strange.

julia

> #define ZR36057_VFESPFR_RGB565 (2 << 3)
> #define ZR36057_VFESPFR_RGB555 (3 << 3)
> -#define ZR36057_VFESPFR_ERR_DIF (1 << 2)
> -#define ZR36057_VFESPFR_PACK24 (1 << 1)
> -#define ZR36057_VFESPFR_LITTLE_ENDIAN (1 << 0)
> +#define ZR36057_VFESPFR_ERR_DIF BIT(2)
> +#define ZR36057_VFESPFR_PACK24 BIT(1)
> +#define ZR36057_VFESPFR_LITTLE_ENDIAN BIT(0)
>
> #define ZR36057_VDTR 0x00c /* Video Display "Top" Register */
>
> --
> 2.30.2
>
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