Re: [Patch v2 1/3] media: ov5640: add PIXEL_RATE control

Jacopo Mondi
2019-10-03T07:15:35Z

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Hi Benoit,

On Wed, Oct 02, 2019 at 08:51:32AM -0500, Benoit Parrot wrote:
> Add v4l2 controls to report the pixel rates of each mode. This is
> needed by some CSI2 receiver in order to perform proper DPHY
> configuration.
>
> Signed-off-by: Benoit Parrot <bparrot@ti.com>
> ---
> drivers/media/i2c/ov5640.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> index 500d9bbff10b..5198dc887400 100644
> --- a/drivers/media/i2c/ov5640.c
> +++ b/drivers/media/i2c/ov5640.c
> @@ -193,6 +193,9 @@ struct ov5640_mode_info {
>
> struct ov5640_ctrls {
> struct v4l2_ctrl_handler handler;
> + struct {
> + struct v4l2_ctrl *pixel_rate;
> + };

Do you need to wrap this v4l2_ctrl in it's own unnamed struct? Other
controls here declared in this way are clustered and, if I'm not
mistaken, using unnamed struct to wrap them is just a typographically
nice way to convey that. I think your new control could be declared
without a wrapping struct { }.

> struct {
> struct v4l2_ctrl *auto_exp;
> struct v4l2_ctrl *exposure;
> @@ -2194,6 +2197,16 @@ static int ov5640_try_fmt_internal(struct v4l2_subdev *sd,
> return 0;
> }
>
> +static u64 ov5640_calc_pixel_rate(struct ov5640_dev *sensor)
> +{
> + u64 rate;
> +
> + rate = sensor->current_mode->vtot * sensor->current_mode->htot;
> + rate *= ov5640_framerates[sensor->current_fr];
> +
> + return rate;
> +}
> +

Just to point out this is the -theoretical- pixel rate, and might be
quite different from the one calculated by the clock tree tuning
procedure (which should be updated to match Hugues' latest findings).

> static int ov5640_set_fmt(struct v4l2_subdev *sd,
> struct v4l2_subdev_pad_config *cfg,
> struct v4l2_subdev_format *format)
> @@ -2233,6 +2246,8 @@ static int ov5640_set_fmt(struct v4l2_subdev *sd,
> if (mbus_fmt->code != sensor->fmt.code)
> sensor->pending_fmt_change = true;
>
> + __v4l2_ctrl_s_ctrl_int64(sensor->ctrls.pixel_rate,
> + ov5640_calc_pixel_rate(sensor));
> out:
> mutex_unlock(&sensor->lock);
> return ret;
> @@ -2657,6 +2672,13 @@ static int ov5640_init_controls(struct ov5640_dev *sensor)
> /* we can use our own mutex for the ctrl lock */
> hdl->lock = &sensor->lock;
>
> + /* Clock related controls */
> + ctrls->pixel_rate =
> + v4l2_ctrl_new_std(hdl, ops,

If you like it better, this could fit in 1 line

ctrls->pixel_rate = v4l2_ctrl_new_std(hdl, ops, V4L2_CID_PIXEL_RATE,
0, INT_MAX, 1,
ov5640_calc_pixel_rate(sensor)

Thanks
j

> + V4L2_CID_PIXEL_RATE, 0, INT_MAX, 1,
> + ov5640_calc_pixel_rate(sensor));

> + ctrls->pixel_rate->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> +
> /* Auto/manual white balance */
> ctrls->auto_wb = v4l2_ctrl_new_std(hdl, ops,
> V4L2_CID_AUTO_WHITE_BALANCE,
> @@ -2816,6 +2838,9 @@ static int ov5640_s_frame_interval(struct v4l2_subdev *sd,
> sensor->frame_interval = fi->interval;
> sensor->current_mode = mode;
> sensor->pending_mode_change = true;
> +
> + __v4l2_ctrl_s_ctrl_int64(sensor->ctrls.pixel_rate,
> + ov5640_calc_pixel_rate(sensor));
> }
> out:
> mutex_unlock(&sensor->lock);
> --
> 2.17.1
>

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