linux-kernel - Re: [PATCH 05/19] media: i2c: ov4689: Refactor ov4689_set

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Message-ID: <20231211181106.GD27535@pendragon.ideasonboard.com>
Date:   Mon, 11 Dec 2023 20:11:06 +0200
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Mikhail Rudenko <mike.rudenko@...il.com>
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Jacopo Mondi <jacopo@...ndi.org>,
        Tommaso Merciai <tommaso.merciai@...rulasolutions.com>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Subject: Re: [PATCH 05/19] media: i2c: ov4689: Refactor ov4689_set_ctrl

Hi Mikhail,

Thank you for the patch.

On Mon, Dec 11, 2023 at 08:50:08PM +0300, Mikhail Rudenko wrote:
> Introduces local variables for regmap and the control value within the
> ov4689_set_ctrl function. This adjustment eliminates repetition within
> the function.
> 
> Signed-off-by: Mikhail Rudenko <mike.rudenko@...il.com>
> ---
>  drivers/media/i2c/ov4689.c | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
> index 8c120d7f7830..42700ecfbe0e 100644
> --- a/drivers/media/i2c/ov4689.c
> +++ b/drivers/media/i2c/ov4689.c
> @@ -584,7 +584,9 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>  {
>  	struct ov4689 *ov4689 =
>  		container_of(ctrl->handler, struct ov4689, ctrl_handler);
> +	struct regmap *regmap = ov4689->regmap;
>  	struct device *dev = ov4689->dev;
> +	s32 val = ctrl->val;

For ctrl->val, I think the code is clearer without this change. When
reading the function, seeing "val", I need to look up what it is, while
seeing "ctrl->val" gives me more context and makes (in my opinion) the
code more readable.

>  	int sensor_gain;
>  	s64 max_expo;
>  	int ret;
> @@ -593,7 +595,7 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>  	switch (ctrl->id) {
>  	case V4L2_CID_VBLANK:
>  		/* Update max exposure while meeting expected vblanking */
> -		max_expo = ov4689->cur_mode->height + ctrl->val - 4;
> +		max_expo = ov4689->cur_mode->height + val - 4;
>  		__v4l2_ctrl_modify_range(ov4689->exposure,
>  					 ov4689->exposure->minimum, max_expo,
>  					 ov4689->exposure->step,
> @@ -607,36 +609,34 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>  	switch (ctrl->id) {
>  	case V4L2_CID_EXPOSURE:
>  		/* 4 least significant bits of exposure are fractional part */
> -		ret = cci_write(ov4689->regmap, OV4689_REG_EXPOSURE,
> -				ctrl->val << 4, NULL);
> +		cci_write(regmap, OV4689_REG_EXPOSURE, val << 4, &ret);
>  		break;
>  	case V4L2_CID_ANALOGUE_GAIN:
> -		ret = ov4689_map_gain(ov4689, ctrl->val, &sensor_gain);
> +		ret = ov4689_map_gain(ov4689, val, &sensor_gain);
>  
> -		cci_write(ov4689->regmap, OV4689_REG_GAIN_H,
> +		cci_write(regmap, OV4689_REG_GAIN_H,
>  			  (sensor_gain >> OV4689_GAIN_H_SHIFT) &
>  			  OV4689_GAIN_H_MASK, &ret);
>  
> -		cci_write(ov4689->regmap, OV4689_REG_GAIN_L,
> +		cci_write(regmap, OV4689_REG_GAIN_L,
>  			  sensor_gain & OV4689_GAIN_L_MASK,
>  			  &ret);
>  		break;
>  	case V4L2_CID_VBLANK:
> -		ret = cci_write(ov4689->regmap, OV4689_REG_VTS,
> -				ctrl->val + ov4689->cur_mode->height, NULL);
> +		cci_write(regmap, OV4689_REG_VTS,
> +			  val + ov4689->cur_mode->height, &ret);
>  		break;
>  	case V4L2_CID_TEST_PATTERN:
> -		ret = ov4689_enable_test_pattern(ov4689, ctrl->val);
> +		ret = ov4689_enable_test_pattern(ov4689, val);
>  		break;
>  	default:
>  		dev_warn(dev, "%s Unhandled id:0x%x, val:0x%x\n",
> -			 __func__, ctrl->id, ctrl->val);
> +			 __func__, ctrl->id, val);
>  		ret = -EINVAL;
>  		break;
>  	}
>  
>  	pm_runtime_put(dev);
> -
>  	return ret;
>  }
>  
> -- 
> 2.43.0
> 

-- 
Regards,

Laurent Pinchart