Re: [PATCH] media: imx219: Report streams using frame descriptors

[Mattijs Korpershoek <mkorpershoek@kernel.org>]

Hi Tomi,

Thank you for the patch.

On Thu, Jun 11, 2026 at 12:13, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> wrote:

> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> Implement the .get_frame_desc() subdev operation to report information
> about streams to the connected CSI-2 receiver. This is required to let
> the CSI-2 receiver driver know about virtual channels and data types for
> each stream.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> [tomi.valkeinen: picked from "Generic line based metadata support, internal pads" series]
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> This patch that adds .get_frame_desc() support to imx219 driver has been
> circulating for a few years, and is currently posted in "[PATCH v12
> 00/86] Generic line based metadata support, internal pads" series.
>
> However, as some bridge drivers require modern drivers that support
> .get_frame_desc, specifically ds90ub960.c, let's pick the patch and
> queue it separately from the huge metadata series.
> ---
>  drivers/media/i2c/imx219.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)

Note: I understand that this is not the preferred solution because there
is [1]. I still found value on testing this so:

Tested-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

Details:
This is the only patch I needed on top of linux/master to get camera
working on a TI AM69-SK.

I used a AM69-SK with the Arducam FPD V3Link[2] using
the following device tree overlays:
  ti/k3-am68-sk-v3link-fusion.dtbo ti/k3-v3link-imx219-0-0.dtbo

See TI's documentation about this [3]

[1] https://lore.kernel.org/linux-media/20260518164318.3367888-1-sakari.ailus@linux.intel.com/
[2] https://www.arducam.com/arducam-v3link-camera-kit-for-ti-development-boards.html
[3]
https://software-dl.ti.com/jacinto7/esd/processor-sdk-linux-am69/11_00_10_01/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Camera/CSI2RX.html

Some review comment below.

>
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index 223d3753cc93..7829ddc115a0 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -23,6 +23,7 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
>  
> +#include <media/mipi-csi2.h>
>  #include <media/v4l2-cci.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
> @@ -661,6 +662,24 @@ static void imx219_free_controls(struct imx219 *imx219)
>   * Subdev operations
>   */
>  
> +static unsigned int imx219_format_bpp(u32 code)
> +{
> +	switch (code) {
> +	case MEDIA_BUS_FMT_SRGGB8_1X8:
> +	case MEDIA_BUS_FMT_SGRBG8_1X8:
> +	case MEDIA_BUS_FMT_SGBRG8_1X8:
> +	case MEDIA_BUS_FMT_SBGGR8_1X8:
> +		return 8;
> +
> +	case MEDIA_BUS_FMT_SRGGB10_1X10:
> +	case MEDIA_BUS_FMT_SGRBG10_1X10:
> +	case MEDIA_BUS_FMT_SGBRG10_1X10:
> +	case MEDIA_BUS_FMT_SBGGR10_1X10:
> +	default:
> +		return 10;
> +	}
> +}
> +

Do we need this function when we already have imx219_get_format_bpp()
which does the same thing?

>  static int imx219_set_framefmt(struct imx219 *imx219,
>  			       struct v4l2_subdev_state *state)
>  {
> @@ -969,6 +988,30 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
>  	return -EINVAL;
>  }
>  
> +static int imx219_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
> +				 struct v4l2_mbus_frame_desc *fd)
> +{
> +	const struct v4l2_mbus_framefmt *fmt;
> +	struct v4l2_subdev_state *state;
> +	u32 code;
> +
> +	state = v4l2_subdev_lock_and_get_active_state(sd);

Do we need error handling here? v4l2_subdev_lock_and_get_active_state()
can return NULL.

> +	fmt = v4l2_subdev_state_get_format(state, 0);
> +	code = fmt->code;
> +	v4l2_subdev_unlock_state(state);
> +
> +	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
> +	fd->num_entries = 1;
> +
> +	fd->entry[0].pixelcode = code;
> +	fd->entry[0].stream = 0;
> +	fd->entry[0].bus.csi2.vc = 0;
> +	fd->entry[0].bus.csi2.dt = imx219_format_bpp(code) == 8 ?
> +		MIPI_CSI2_DT_RAW8 : MIPI_CSI2_DT_RAW10;
> +
> +	return 0;
> +}
> +
>  static int imx219_init_state(struct v4l2_subdev *sd,
>  			     struct v4l2_subdev_state *state)
>  {
> @@ -995,6 +1038,7 @@ static const struct v4l2_subdev_pad_ops imx219_pad_ops = {
>  	.set_fmt = imx219_set_pad_format,
>  	.get_selection = imx219_get_selection,
>  	.enum_frame_size = imx219_enum_frame_size,
> +	.get_frame_desc = imx219_get_frame_desc,
>  	.enable_streams = imx219_enable_streams,
>  	.disable_streams = imx219_disable_streams,
>  };
>
> ---
> base-commit: 06cb687a5132fcffe624c0070576ab852ac6b568
> change-id: 20260611-imx219-frame-desc-9cc223b1fbd5
>
> Best regards,
> --  
> Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>