Re: [Outreachy kernel] [PATCH] Staging: media: imx: Prefer using BIT macro

From: Sean Paul
Date: Fri Sep 08 2017 - 11:30:02 EST


On Fri, Sep 8, 2017 at 11:11 AM, Srishti Sharma <srishtishar@xxxxxxxxx> wrote:
> Use BIT(x) instead of (1<<x).
>
> Signed-off-by: Srishti Sharma <srishtishar@xxxxxxxxx>
> ---
> drivers/staging/media/imx/imx-media.h | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/staging/media/imx/imx-media.h b/drivers/staging/media/imx/imx-media.h
> index d409170..e5b8d29 100644
> --- a/drivers/staging/media/imx/imx-media.h
> +++ b/drivers/staging/media/imx/imx-media.h
> @@ -310,16 +310,16 @@ void imx_media_capture_device_set_format(struct imx_media_video_dev *vdev,
> void imx_media_capture_device_error(struct imx_media_video_dev *vdev);
>
> /* subdev group ids */
> -#define IMX_MEDIA_GRP_ID_SENSOR (1 << 8)
> -#define IMX_MEDIA_GRP_ID_VIDMUX (1 << 9)
> -#define IMX_MEDIA_GRP_ID_CSI2 (1 << 10)
> +#define IMX_MEDIA_GRP_ID_SENSOR BIT(8)
> +#define IMX_MEDIA_GRP_ID_VIDMUX BIT(9)
> +#define IMX_MEDIA_GRP_ID_CSI2 BIT(10)
> #define IMX_MEDIA_GRP_ID_CSI_BIT 11
> #define IMX_MEDIA_GRP_ID_CSI (0x3 << IMX_MEDIA_GRP_ID_CSI_BIT)
> -#define IMX_MEDIA_GRP_ID_CSI0 (1 << IMX_MEDIA_GRP_ID_CSI_BIT)
> +#define IMX_MEDIA_GRP_ID_CSI0 BIT(IMX_MEDIA_GRP_ID_CSI_BIT)
> #define IMX_MEDIA_GRP_ID_CSI1 (2 << IMX_MEDIA_GRP_ID_CSI_BIT)
> -#define IMX_MEDIA_GRP_ID_VDIC (1 << 13)
> -#define IMX_MEDIA_GRP_ID_IC_PRP (1 << 14)
> -#define IMX_MEDIA_GRP_ID_IC_PRPENC (1 << 15)
> -#define IMX_MEDIA_GRP_ID_IC_PRPVF (1 << 16)
> +#define IMX_MEDIA_GRP_ID_VDIC BIT(13)
> +#define IMX_MEDIA_GRP_ID_IC_PRP BIT(14)
> +#define IMX_MEDIA_GRP_ID_IC_PRPENC BIT(15)
> +#define IMX_MEDIA_GRP_ID_IC_PRPVF BIT(16)

Hi Srishti,
Thanks for your patch.

Perhaps this is just personal preference, but I find the previous
version more readable. Since IMX_MEDIA_GRP_ID_CSI and
IMX_MEDIA_GRP_ID_CSI1 are multi-bit fields, you can't fully eliminate
the bit shift operations, so you end up with a mix, which is kind of
ugly.

Sean

>
> #endif
> --
> 2.7.4
>
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