linux-kernel - Re: [PATCH 06/19] media: i2c: ov4689: Set gain in one 16 bit write

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Date:   Mon, 11 Dec 2023 20:11:54 +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 06/19] media: i2c: ov4689: Set gain in one 16 bit write

On Mon, Dec 11, 2023 at 08:50:09PM +0300, Mikhail Rudenko wrote:
> According to the datasheet, bits 0-7 of the AEC LONG GAIN
> register (0x3508) map to bits 8-15 of the gain value and no masking is
> required. Thus set analogue gain in a single 16-bit write instead of
> two 8-bit writes.
> 
> Signed-off-by: Mikhail Rudenko <mike.rudenko@...il.com>

You could squash it with patch 03/19.

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
>  drivers/media/i2c/ov4689.c | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
> index 42700ecfbe0e..5392f650960c 100644
> --- a/drivers/media/i2c/ov4689.c
> +++ b/drivers/media/i2c/ov4689.c
> @@ -32,11 +32,7 @@
>  #define OV4689_EXPOSURE_STEP		1
>  #define OV4689_VTS_MAX			0x7fff
>  
> -#define OV4689_REG_GAIN_H		CCI_REG8(0x3508)
> -#define OV4689_REG_GAIN_L		CCI_REG8(0x3509)
> -#define OV4689_GAIN_H_MASK		0x07
> -#define OV4689_GAIN_H_SHIFT		8
> -#define OV4689_GAIN_L_MASK		0xff
> +#define OV4689_REG_GAIN			CCI_REG16(0x3508)
>  #define OV4689_GAIN_STEP		1
>  #define OV4689_GAIN_DEFAULT		0x80
>  
> @@ -613,14 +609,7 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>  		break;
>  	case V4L2_CID_ANALOGUE_GAIN:
>  		ret = ov4689_map_gain(ov4689, val, &sensor_gain);
> -
> -		cci_write(regmap, OV4689_REG_GAIN_H,
> -			  (sensor_gain >> OV4689_GAIN_H_SHIFT) &
> -			  OV4689_GAIN_H_MASK, &ret);
> -
> -		cci_write(regmap, OV4689_REG_GAIN_L,
> -			  sensor_gain & OV4689_GAIN_L_MASK,
> -			  &ret);
> +		cci_write(regmap, OV4689_REG_GAIN, sensor_gain, &ret);
>  		break;
>  	case V4L2_CID_VBLANK:
>  		cci_write(regmap, OV4689_REG_VTS,

-- 
Regards,

Laurent Pinchart