[v4,18/20] media: i2c: imx219: Calculate crop rectangle dynamically

Calculate the crop rectangle size and location dynamically when setting
the format, instead of storing it in the imx219_mode structure. This
removes duplicated information from the mode, to guarantee consistency.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
Changes since v2:

- Handle horizontal and vertical binning separately
---
 drivers/media/i2c/imx219.c | 45 +++++++++++++-------------------------
 1 file changed, 15 insertions(+), 30 deletions(-)

Hi Laurent

On Sun, 24 Sept 2023 at 16:33, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Calculate the crop rectangle size and location dynamically when setting
> the format, instead of storing it in the imx219_mode structure. This
> removes duplicated information from the mode, to guarantee consistency.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> ---
> Changes since v2:
>
> - Handle horizontal and vertical binning separately
> ---
>  drivers/media/i2c/imx219.c | 45 +++++++++++++-------------------------
>  1 file changed, 15 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index bf1c2a1dad95..2b88c5b8a7bf 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -18,6 +18,7 @@
>  #include <linux/delay.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
> +#include <linux/minmax.h>
>  #include <linux/module.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
> @@ -153,9 +154,6 @@ struct imx219_mode {
>         /* Frame height */
>         unsigned int height;
>
> -       /* Analog crop rectangle. */
> -       struct v4l2_rect crop;
> -
>         /* V-timing */
>         unsigned int vts_def;
>  };
> @@ -292,48 +290,24 @@ static const struct imx219_mode supported_modes[] = {
>                 /* 8MPix 15fps mode */
>                 .width = 3280,
>                 .height = 2464,
> -               .crop = {
> -                       .left = IMX219_PIXEL_ARRAY_LEFT,
> -                       .top = IMX219_PIXEL_ARRAY_TOP,
> -                       .width = 3280,
> -                       .height = 2464
> -               },
>                 .vts_def = 3526,
>         },
>         {
>                 /* 1080P 30fps cropped */
>                 .width = 1920,
>                 .height = 1080,
> -               .crop = {
> -                       .left = 688,
> -                       .top = 700,
> -                       .width = 1920,
> -                       .height = 1080
> -               },
>                 .vts_def = 1763,
>         },
>         {
>                 /* 2x2 binned 30fps mode */
>                 .width = 1640,
>                 .height = 1232,
> -               .crop = {
> -                       .left = IMX219_PIXEL_ARRAY_LEFT,
> -                       .top = IMX219_PIXEL_ARRAY_TOP,
> -                       .width = 3280,
> -                       .height = 2464
> -               },
>                 .vts_def = 1763,
>         },
>         {
>                 /* 640x480 30fps mode */
>                 .width = 640,
>                 .height = 480,
> -               .crop = {
> -                       .left = 1008,
> -                       .top = 760,
> -                       .width = 1280,
> -                       .height = 960
> -               },
>                 .vts_def = 1763,
>         },
>  };
> @@ -844,6 +818,7 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>         int exposure_max, exposure_def, hblank;
>         struct v4l2_mbus_framefmt *format;
>         struct v4l2_rect *crop;
> +       unsigned int bin_h, bin_v;
>
>         mode = v4l2_find_nearest_size(supported_modes,
>                                       ARRAY_SIZE(supported_modes),
> @@ -853,10 +828,20 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>         imx219_update_pad_format(imx219, mode, &fmt->format, fmt->format.code);
>
>         format = v4l2_subdev_get_pad_format(sd, sd_state, 0);
> -       crop = v4l2_subdev_get_pad_crop(sd, sd_state, 0);
> -
>         *format = fmt->format;
> -       *crop = mode->crop;
> +
> +       /*
> +        * Use binning to maximize the crop rectangle size, and centre it in the
> +        * sensor.
> +        */
> +       bin_h = min(IMX219_PIXEL_ARRAY_WIDTH / format->width, 2U);
> +       bin_v = min(IMX219_PIXEL_ARRAY_HEIGHT / format->height, 2U);

This patch missed 6.6 as the previous LTS, so we've only just noticed
this regression with 6.12. It's also present in 6.15-rc2.

The 1920x1080 mode will give you bin_h of 1, but bin_v of 2 as 1080 <
(2480/2). You therefore get a weirdly stretched image from the sensor.

I accept that having a nicely generic cropping/binning configuration
is ideal, but currently this is a mode based driver, and there is no
API to allow for configuring generic cropping/binning configuration.
Until that API exists and can be implemented for previously mode-based
drivers without regression, I see the only real options being either
- move the binning setup back into struct imx219_mode and defined in
supported modes
- set the two binning values to be the same as the minimum of the two
computed values.
Which would be preferred?

Thanks
  Dave

> +
> +       crop = v4l2_subdev_get_pad_crop(sd, sd_state, 0);
> +       crop->width = format->width * bin_h;
> +       crop->height = format->height * bin_v;
> +       crop->left = (IMX219_NATIVE_WIDTH - crop->width) / 2;
> +       crop->top = (IMX219_NATIVE_HEIGHT - crop->height) / 2;
>
>         if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
>                 /* Update limits and set FPS to default */
> --
> Regards,
>
> Laurent Pinchart
>