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Date: Fri, 23 Feb 2024 08:26:52 +0000
From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: Mikhail Rudenko <mike.rudenko@gmail.com>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Jacopo Mondi <jacopo@jmondi.org>,
	Tommaso Merciai <tomm.merciai@gmail.com>,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>
Subject: Re: [PATCH v2 12/20] media: i2c: ov4689: Implement vflip/hflip
 controls
Message-ID: <ZdhWzCNalXnScMQy@kekkonen.localdomain>
References: <20231218174042.794012-1-mike.rudenko@gmail.com>
 <20231218174042.794012-13-mike.rudenko@gmail.com>
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In-Reply-To: <20231218174042.794012-13-mike.rudenko@gmail.com>

Hi Mikhail,

On Mon, Dec 18, 2023 at 08:40:33PM +0300, Mikhail Rudenko wrote:
> The OV4689 sensor supports horizontal and vertical flipping. Add
> appropriate controls to the driver. Toggling both array flip and
> digital flip bits allows to achieve flipping while maintaining output
> Bayer order. Note that the default value of hflip control corresponds
> to both bits set, as it was before this patch.
> 
> Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com>
> ---
>  drivers/media/i2c/ov4689.c | 24 ++++++++++++++++++++++--
>  1 file changed, 22 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
> index 06ed9d22b2c8..6cf986bf305d 100644
> --- a/drivers/media/i2c/ov4689.c
> +++ b/drivers/media/i2c/ov4689.c
> @@ -42,6 +42,14 @@
>  #define OV4689_REG_VTS			CCI_REG16(0x380e)
>  #define OV4689_VTS_MAX			0x7fff
>  
> +#define OV4689_REG_TIMING_FORMAT1	CCI_REG8(0x3820)
> +#define OV4689_REG_TIMING_FORMAT2	CCI_REG8(0x3821)
> +#define OV4689_TIMING_FLIP_MASK		GENMASK(2, 1)
> +#define OV4689_TIMING_FLIP_ARRAY	BIT(1)
> +#define OV4689_TIMING_FLIP_DIGITAL	BIT(2)
> +#define OV4689_TIMING_FLIP_BOTH		(OV4689_TIMING_FLIP_ARRAY |\
> +					 OV4689_TIMING_FLIP_DIGITAL)
> +
>  #define OV4689_REG_TEST_PATTERN		CCI_REG8(0x5040)
>  #define OV4689_TEST_PATTERN_ENABLE	0x80
>  #define OV4689_TEST_PATTERN_DISABLE	0x0
> @@ -183,7 +191,6 @@ static const struct cci_reg_sequence ov4689_2688x1520_regs[] = {
>  	{CCI_REG8(0x3811), 0x08}, /* H_WIN_OFF_L h_win_off[7:0] = 0x08*/
>  	{CCI_REG8(0x3813), 0x04}, /* V_WIN_OFF_L v_win_off[7:0] = 0x04 */
>  	{CCI_REG8(0x3819), 0x01}, /* VSYNC_END_L vsync_end_point[7:0] = 0x01 */
> -	{CCI_REG8(0x3821), 0x06}, /* TIMING_FORMAT2 array_h_mirror = 1, digital_h_mirror = 1 */
>  
>  	/* OTP control */
>  	{CCI_REG8(0x3d85), 0x36}, /* OTP_REG85 OTP_power_up_load_setting_enable = 1,
> @@ -607,6 +614,16 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>  			  (ctrl->val + ov4689->cur_mode->width) /
>  			  OV4689_HTS_DIVIDER, &ret);
>  		break;
> +	case V4L2_CID_VFLIP:
> +		cci_update_bits(regmap, OV4689_REG_TIMING_FORMAT1,
> +				OV4689_TIMING_FLIP_MASK,
> +				ctrl->val ? OV4689_TIMING_FLIP_BOTH : 0, &ret);
> +		break;
> +	case V4L2_CID_HFLIP:
> +		cci_update_bits(regmap, OV4689_REG_TIMING_FORMAT2,
> +				OV4689_TIMING_FLIP_MASK,
> +				ctrl->val ? 0 : OV4689_TIMING_FLIP_BOTH, &ret);
> +		break;
>  	default:
>  		dev_warn(dev, "%s Unhandled id:0x%x, val:0x%x\n",
>  			 __func__, ctrl->id, ctrl->val);
> @@ -637,7 +654,7 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
>  
>  	handler = &ov4689->ctrl_handler;
>  	mode = ov4689->cur_mode;
> -	ret = v4l2_ctrl_handler_init(handler, 10);
> +	ret = v4l2_ctrl_handler_init(handler, 12);
>  	if (ret)
>  		return ret;
>  
> @@ -677,6 +694,9 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
>  				     ARRAY_SIZE(ov4689_test_pattern_menu) - 1,
>  				     0, 0, ov4689_test_pattern_menu);
>  
> +	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0);
> +	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_HFLIP, 0, 1, 1, 0);

Could you take the default value from the mounting rotation?

The default should be upside-up, but this is an existing driver and
changing the flipping now could affect existing users.
<URL:https://hverkuil.home.xs4all.nl/spec/userspace-api/drivers/camera-sensor.html#rotation-orientation-and-flipping>

> +
>  	if (handler->error) {
>  		ret = handler->error;
>  		dev_err(ov4689->dev, "Failed to init controls(%d)\n", ret);

-- 
Regards,

Sakari Ailus