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Subject: Re: [RFC PATCH v2 12/18] media: tegra-video: Add support for
 selection ioctl ops
To:     Sowjanya Komatineni <skomatineni@nvidia.com>,
        thierry.reding@gmail.com, jonathanh@nvidia.com, frankc@nvidia.com,
        sakari.ailus@iki.fi, robh+dt@kernel.org, helen.koike@collabora.com
Cc:     digetx@gmail.com, sboyd@kernel.org, gregkh@linuxfoundation.org,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-i2c@vger.kernel.org
References: <1592358094-23459-1-git-send-email-skomatineni@nvidia.com>
 <1592358094-23459-13-git-send-email-skomatineni@nvidia.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <efc84cff-76d5-78a2-e84e-0342459d3756@xs4all.nl>
Date:   Thu, 2 Jul 2020 15:54:45 +0200
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On 17/06/2020 03:41, Sowjanya Komatineni wrote:
> This patch adds selection v4l2 ioctl operations to allow configuring
> a selection rectangle in the sensor through the Tegra video device
> node.
> 
> Some sensor drivers supporting crop uses try_crop rectangle from
> v4l2_subdev_pad_config during try format for computing binning.
> 
> So with selection ops support, this patch also updates try format
> to use try crop rectangle either from subdev frame size enumeration
> or from subdev crop boundary.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
>  drivers/staging/media/tegra-video/vi.c | 106 +++++++++++++++++++++++++++++++++
>  1 file changed, 106 insertions(+)
> 
> diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c
> index 506c263..f9eb96b 100644
> --- a/drivers/staging/media/tegra-video/vi.c
> +++ b/drivers/staging/media/tegra-video/vi.c
> @@ -427,6 +427,13 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan,
>  	struct v4l2_subdev *subdev;
>  	struct v4l2_subdev_format fmt;
>  	struct v4l2_subdev_pad_config *pad_cfg;
> +	struct v4l2_subdev_frame_size_enum fse = {
> +		.which = V4L2_SUBDEV_FORMAT_TRY,
> +	};
> +	struct v4l2_subdev_selection sdsel = {
> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +		.target = V4L2_SEL_TGT_CROP_BOUNDS,
> +	};
>  	int ret;
>  
>  	subdev = tegra_channel_get_remote_subdev(chan, true);
> @@ -449,6 +456,24 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan,
>  	fmt.which = V4L2_SUBDEV_FORMAT_TRY;
>  	fmt.pad = 0;
>  	v4l2_fill_mbus_format(&fmt.format, pix, fmtinfo->code);
> +
> +	/*
> +	 * Attempt to obtain the format size from subdev.
> +	 * If not available, try to get crop boundary from subdev.
> +	 */
> +	fse.code = fmtinfo->code;
> +	ret = v4l2_subdev_call(subdev, pad, enum_frame_size, pad_cfg, &fse);
> +	if (ret) {
> +		ret = v4l2_subdev_call(subdev, pad, get_selection, NULL, &sdsel);
> +		if (ret)
> +			return -EINVAL;
> +		pad_cfg->try_crop.width = sdsel.r.width;
> +		pad_cfg->try_crop.height = sdsel.r.height;
> +	} else {
> +		pad_cfg->try_crop.width = fse.max_width;
> +		pad_cfg->try_crop.height = fse.max_height;
> +	}
> +
>  	ret = v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
>  	if (ret < 0)
>  		return ret;
> @@ -540,6 +565,85 @@ static int tegra_channel_set_subdev_active_fmt(struct tegra_vi_channel *chan)
>  	return 0;
>  }
>  
> +static int tegra_channel_g_selection(struct file *file, void *priv,
> +				     struct v4l2_selection *sel)
> +{
> +	struct tegra_vi_channel *chan = video_drvdata(file);
> +	struct v4l2_subdev *subdev;
> +	struct v4l2_subdev_format fmt = {
> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +	};
> +	struct v4l2_subdev_selection sdsel = {
> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +		.target = sel->target,
> +	};
> +	int ret;
> +
> +	if (IS_ENABLED(CONFIG_VIDEO_TEGRA_TPG))
> +		return -ENOTTY;
> +
> +	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +		return -EINVAL;
> +	/*
> +	 * Try the get selection operation and fallback to get format if not
> +	 * implemented.
> +	 */
> +	subdev = tegra_channel_get_remote_subdev(chan, true);
> +	ret = v4l2_subdev_call(subdev, pad, get_selection, NULL, &sdsel);
> +	if (!ret)
> +		sel->r = sdsel.r;
> +	if (ret != -ENOIOCTLCMD)
> +		return ret;
> +
> +	ret = v4l2_subdev_call(subdev, pad, get_fmt, NULL, &fmt);
> +	if (ret < 0)
> +		return ret;
> +
> +	sel->r.left = 0;
> +	sel->r.top = 0;
> +	sel->r.width = fmt.format.width;
> +	sel->r.height = fmt.format.height;
> +
> +	return 0;
> +}
> +
> +static int tegra_channel_s_selection(struct file *file, void *fh,
> +				     struct v4l2_selection *sel)
> +{
> +	struct tegra_vi_channel *chan = video_drvdata(file);
> +	struct v4l2_subdev *subdev;
> +	int ret;
> +	struct v4l2_subdev_selection sdsel = {
> +		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +		.target = sel->target,
> +		.flags = sel->flags,
> +		.r = sel->r,
> +	};
> +

This function doesn't check if the subdev actually supports set_selection.
The imx219 is one such driver: it supports get_selection, but not set_selection.

So this code should add these lines to fix the v4l2-compliance fail:

       subdev = tegra_channel_get_remote_subdev(chan, true);

       if (!v4l2_subdev_has_op(subdev, pad, set_selection))
               return -ENOTTY;


> +	if (IS_ENABLED(CONFIG_VIDEO_TEGRA_TPG))
> +		return -ENOTTY;
> +
> +	if (sel->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
> +		return -EINVAL;
> +
> +	if (vb2_is_busy(&chan->queue))
> +		return -EBUSY;
> +
> +	subdev = tegra_channel_get_remote_subdev(chan, true);

And this line can be dropped.

Regards,

	Hans

> +	ret = v4l2_subdev_call(subdev, pad, set_selection, NULL, &sdsel);
> +	if (!ret) {
> +		sel->r = sdsel.r;
> +		/*
> +		 * Subdev active format resolution may have changed during
> +		 * set selection operation. So, update channel format to
> +		 * the sub-device active format.
> +		 */
> +		return tegra_channel_set_subdev_active_fmt(chan);
> +	}
> +
> +	return ret;
> +}
> +
>  static int tegra_channel_enum_input(struct file *file, void *fh,
>  				    struct v4l2_input *inp)
>  {
> @@ -597,6 +701,8 @@ static const struct v4l2_ioctl_ops tegra_channel_ioctl_ops = {
>  	.vidioc_streamoff		= vb2_ioctl_streamoff,
>  	.vidioc_subscribe_event		= v4l2_ctrl_subscribe_event,
>  	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
> +	.vidioc_g_selection		= tegra_channel_g_selection,
> +	.vidioc_s_selection		= tegra_channel_s_selection,
>  };
>  
>  /*
>