Re: [PATCH 11/11] media: i2c: imx290: Add support for H & V Flips

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi Dave,

thanks for the patch.

Am Dienstag, 31. Januar 2023, 20:20:16 CET schrieb Dave Stevenson:
> The sensor supports H & V flips, so add the relevant hooks for
> V4L2_CID_HFLIP and V4L2_CID_VFLIP to configure them.
> 
> Note that the Bayer order is maintained as the readout area
> shifts by 1 pixel in the appropriate direction (note the
> comment about the top margin being 8 pixels whilst the bottom
> margin is 9). The V4L2_SEL_TGT_CROP region is therefore
> adjusted appropriately.
> 
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> ---
>  drivers/media/i2c/imx290.c | 37 ++++++++++++++++++++++++++++++++++---
>  1 file changed, 34 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c
> index 7f6746f74040..d2b7534f2c51 100644
> --- a/drivers/media/i2c/imx290.c
> +++ b/drivers/media/i2c/imx290.c
> @@ -227,6 +227,8 @@ struct imx290 {
>  	struct v4l2_ctrl *hblank;
>  	struct v4l2_ctrl *vblank;
>  	struct v4l2_ctrl *exposure;
> +	struct v4l2_ctrl *hflip;
> +	struct v4l2_ctrl *vflip;
>  };
> 
>  static inline struct imx290 *to_imx290(struct v4l2_subdev *_sd)
> @@ -801,6 +803,24 @@ static int imx290_set_ctrl(struct v4l2_ctrl *ctrl)
>  				   NULL);
>  		break;
> 
> +	case V4L2_CID_HFLIP:
> +	case V4L2_CID_VFLIP:
> +	{
> +		u32 reg;
> +
> +		/* WINMODE is in bits [6:4], so need to read-modify-write 
*/
> +		ret = imx290_read(imx290, IMX290_CTRL_07, &reg);
> +		if (ret)
> +			break;
> +		reg &= ~(IMX290_HREVERSE | IMX290_VREVERSE);
> +		if (imx290->hflip->val)
> +			reg |= IMX290_HREVERSE;
> +		if (imx290->vflip->val)
> +			reg |= IMX290_VREVERSE;
> +		ret = imx290_write(imx290, IMX290_CTRL_07, reg, NULL);
> +		break;
> +	}

Given the grab while streaming is on, it can't be changed while streaming. But 
then again the pm_runtime check above will prevent setting the registers while 
streaming is off.

> +
>  	default:
>  		ret = -EINVAL;
>  		break;
> @@ -853,7 +873,7 @@ static int imx290_ctrl_init(struct imx290 *imx290)
>  	if (ret < 0)
>  		return ret;
> 
> -	v4l2_ctrl_handler_init(&imx290->ctrls, 9);
> +	v4l2_ctrl_handler_init(&imx290->ctrls, 11);
> 
>  	/*
>  	 * The sensor has an analog gain and a digital gain, both controlled
> @@ -909,6 +929,11 @@ static int imx290_ctrl_init(struct imx290 *imx290)
>  	imx290->vblank = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
>  					   V4L2_CID_VBLANK, 1, 1, 1, 
1);
> 
> +	imx290->hflip = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
> +					  V4L2_CID_HFLIP, 0, 1, 1, 
0);
> +	imx290->vflip = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
> +					  V4L2_CID_VFLIP, 0, 1, 1, 
0);
> +
>  	v4l2_ctrl_new_fwnode_properties(&imx290->ctrls, &imx290_ctrl_ops,
>  					&props);
> 
> @@ -1030,6 +1055,9 @@ static int imx290_set_stream(struct v4l2_subdev *sd,
> int enable) pm_runtime_put_autosuspend(imx290->dev);
>  	}
> 
> +	/* vflip and hflip cannot change during streaming */
> +	__v4l2_ctrl_grab(imx290->vflip, enable);
> +	__v4l2_ctrl_grab(imx290->hflip, enable);

Why is this grab necessary? While trying to remove these lines, I can flip the 
image while streaming.

Best regards,
Alexander

>  unlock:
>  	v4l2_subdev_unlock_state(state);
>  	return ret;
> @@ -1115,6 +1143,7 @@ static int imx290_get_selection(struct v4l2_subdev
> *sd, struct v4l2_subdev_state *sd_state,
>  				struct v4l2_subdev_selection *sel)
>  {
> +	struct imx290 *imx290 = to_imx290(sd);
>  	struct v4l2_mbus_framefmt *format;
> 
>  	switch (sel->target) {
> @@ -1122,9 +1151,11 @@ static int imx290_get_selection(struct v4l2_subdev
> *sd, format = v4l2_subdev_get_pad_format(sd, sd_state, 0);
> 
>  		sel->r.top = IMX920_PIXEL_ARRAY_MARGIN_TOP
> -			   + (IMX290_PIXEL_ARRAY_RECORDING_HEIGHT - 
format->height) / 2;
> +			   + (IMX290_PIXEL_ARRAY_RECORDING_HEIGHT - 
format->height) / 2
> +			   + imx290->vflip->val;
>  		sel->r.left = IMX920_PIXEL_ARRAY_MARGIN_LEFT
> -			    + (IMX290_PIXEL_ARRAY_RECORDING_WIDTH - 
format->width) / 2;
> +			    + (IMX290_PIXEL_ARRAY_RECORDING_WIDTH - 
format->width) / 2
> +			    + imx290->hflip->val;
>  		sel->r.width = format->width;
>  		sel->r.height = format->height;