Re: [PATCH v6 02/15] media: i2c: imx219: Add internal image sink pad

[Jacopo Mondi <jacopo.mondi@ideasonboard.com>]

Hi Laurent

On Fri, Mar 01, 2024 at 11:32:17PM +0200, Laurent Pinchart wrote:
> Use the newly added internal pad API to expose the internal
> configuration of the sensor to userspace in a standard manner. This also
> paves the way for adding support for embedded data with an additional
> internal pad.
>
> To maintain compatibility with existing userspace that may operate on
> pad 0 unconditionally, keep the source pad numbered 0 and number the
> internal image pad 1.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/i2c/imx219.c | 169 +++++++++++++++++++++++++++++--------
>  1 file changed, 133 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index 3878da50860e..817bf192e4d9 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -140,6 +140,7 @@
>  #define IMX219_DEFAULT_LINK_FREQ_4LANE	363000000
>
>  /* IMX219 native and active pixel array size. */
> +#define IMX219_NATIVE_FORMAT		MEDIA_BUS_FMT_SRGGB10_1X10
>  #define IMX219_NATIVE_WIDTH		3296U
>  #define IMX219_NATIVE_HEIGHT		2480U
>  #define IMX219_PIXEL_ARRAY_LEFT		8U
> @@ -312,9 +313,15 @@ static const struct imx219_mode supported_modes[] = {
>  	},
>  };
>
> +enum imx219_pad_ids {
> +	IMX219_PAD_SOURCE,
> +	IMX219_PAD_IMAGE,

Feels a bit weird for the internal source pad to be named "Image" as
it will (if I understand correctly) host both the image and metadata
streams.

However, I have an hard time proposing a different name, but we should
find something that should be used in all drivers ported to this new
API.

Enough with bikeshedding anyway, this is a tiny detail.

> +	IMX219_NUM_PADS,
> +};
> +
>  struct imx219 {
>  	struct v4l2_subdev sd;
> -	struct media_pad pad;
> +	struct media_pad pads[IMX219_NUM_PADS];
>
>  	struct regmap *regmap;
>  	struct clk *xclk; /* system clock to IMX219 */
> @@ -374,7 +381,7 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
>  	int ret = 0;
>
>  	state = v4l2_subdev_get_locked_active_state(&imx219->sd);
> -	format = v4l2_subdev_state_get_format(state, 0);
> +	format = v4l2_subdev_state_get_format(state, IMX219_PAD_SOURCE);
>
>  	if (ctrl->id == V4L2_CID_VBLANK) {
>  		int exposure_max, exposure_def;
> @@ -593,8 +600,8 @@ static int imx219_set_framefmt(struct imx219 *imx219,
>  	u64 bin_h, bin_v;
>  	int ret = 0;
>
> -	format = v4l2_subdev_state_get_format(state, 0);
> -	crop = v4l2_subdev_state_get_crop(state, 0);
> +	format = v4l2_subdev_state_get_format(state, IMX219_PAD_SOURCE);
> +	crop = v4l2_subdev_state_get_crop(state, IMX219_PAD_IMAGE);
>
>  	switch (format->code) {
>  	case MEDIA_BUS_FMT_SRGGB8_1X8:
> @@ -764,10 +771,25 @@ static int imx219_enum_mbus_code(struct v4l2_subdev *sd,
>  {
>  	struct imx219 *imx219 = to_imx219(sd);
>
> -	if (code->index >= (ARRAY_SIZE(imx219_mbus_formats) / 4))
> -		return -EINVAL;
> +	if (code->pad == IMX219_PAD_IMAGE) {
> +		/* The internal image pad is hardwired to the native format. */
> +		if (code->index)
> +			return -EINVAL;
>
> -	code->code = imx219_get_format_code(imx219, imx219_mbus_formats[code->index * 4]);
> +		code->code = IMX219_NATIVE_FORMAT;

If you return 0 here you can spare the else {} branch. Same in the
function below.

> +	} else {
> +		/*
> +		 * On the source pad, the sensor supports multiple raw formats
> +		 * with different bit depths.
> +		 */
> +		u32 format;
> +
> +		if (code->index >= (ARRAY_SIZE(imx219_mbus_formats) / 4))
> +			return -EINVAL;
> +
> +		format = imx219_mbus_formats[code->index * 4];
> +		code->code = imx219_get_format_code(imx219, format);
> +	}
>
>  	return 0;
>  }
> @@ -777,19 +799,25 @@ static int imx219_enum_frame_size(struct v4l2_subdev *sd,
>  				  struct v4l2_subdev_frame_size_enum *fse)
>  {
>  	struct imx219 *imx219 = to_imx219(sd);
> -	u32 code;
>
> -	if (fse->index >= ARRAY_SIZE(supported_modes))
> -		return -EINVAL;
> +	if (fse->pad == IMX219_PAD_IMAGE) {
> +		if (fse->code != IMX219_NATIVE_FORMAT || fse->index > 0)
> +			return -EINVAL;
>
> -	code = imx219_get_format_code(imx219, fse->code);
> -	if (fse->code != code)
> -		return -EINVAL;
> +		fse->min_width = IMX219_NATIVE_WIDTH;
> +		fse->max_width = IMX219_NATIVE_WIDTH;
> +		fse->min_height = IMX219_NATIVE_HEIGHT;
> +		fse->max_height = IMX219_NATIVE_HEIGHT;
> +	} else {
> +		if (fse->code != imx219_get_format_code(imx219, fse->code) ||
> +		    fse->index >= ARRAY_SIZE(supported_modes))
> +			return -EINVAL;
>
> -	fse->min_width = supported_modes[fse->index].width;
> -	fse->max_width = fse->min_width;
> -	fse->min_height = supported_modes[fse->index].height;
> -	fse->max_height = fse->min_height;
> +		fse->min_width = supported_modes[fse->index].width;
> +		fse->max_width = fse->min_width;
> +		fse->min_height = supported_modes[fse->index].height;
> +		fse->max_height = fse->min_height;
> +	}
>
>  	return 0;
>  }
> @@ -801,9 +829,17 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>  	struct imx219 *imx219 = to_imx219(sd);
>  	const struct imx219_mode *mode;
>  	struct v4l2_mbus_framefmt *format;
> +	struct v4l2_rect *compose;
>  	struct v4l2_rect *crop;
>  	unsigned int bin_h, bin_v;
>
> +	/*
> +	 * The driver is mode-based, the format can be set on the source pad
> +	 * only.
> +	 */
> +	if (fmt->pad != IMX219_PAD_SOURCE)
> +		return v4l2_subdev_get_fmt(sd, state, fmt);
> +
>  	/*
>  	 * Adjust the requested format to match the closest mode. The Bayer
>  	 * order varies with flips.
> @@ -822,22 +858,51 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>  	fmt->format.quantization = V4L2_QUANTIZATION_FULL_RANGE;
>  	fmt->format.xfer_func = V4L2_XFER_FUNC_NONE;
>
> -	format = v4l2_subdev_state_get_format(state, 0);
> +	/* Propagate the format through the sensor. */
> +
> +	/* The image pad models the pixel array, and thus has a fixed size. */
> +	format = v4l2_subdev_state_get_format(state, IMX219_PAD_IMAGE);
>  	*format = fmt->format;

Is this assignment needed ?

Isn't 'fmt' meant to be applied at pad #0 ? Also, you overwrite the
code and size below, do the rest of the 'struct v4l2_mbus_framefmt'
fields apply to pad #1 (field, colorspace, quantization etc ? If pad
#1 represents the pixel array, I don't think they do).

Also, can't the pad #1 format be initialized by .init_state() and never
touched again ?


> +	format->code = IMX219_NATIVE_FORMAT;
> +	format->width = IMX219_NATIVE_WIDTH;
> +	format->height = IMX219_NATIVE_HEIGHT;
>
>  	/*
>  	 * 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);
> +	bin_h = min(IMX219_PIXEL_ARRAY_WIDTH / fmt->format.width, 2U);
> +	bin_v = min(IMX219_PIXEL_ARRAY_HEIGHT / fmt->format.height, 2U);
>
> -	crop = v4l2_subdev_state_get_crop(state, 0);
> -	crop->width = format->width * bin_h;
> -	crop->height = format->height * bin_v;
> +	crop = v4l2_subdev_state_get_crop(state, IMX219_PAD_IMAGE);
> +	crop->width = fmt->format.width * bin_h;
> +	crop->height = fmt->format.height * bin_v;
>  	crop->left = (IMX219_NATIVE_WIDTH - crop->width) / 2;
>  	crop->top = (IMX219_NATIVE_HEIGHT - crop->height) / 2;

This is no different than before, but I now wonder if VGA is actually
obtained by cropping down to 1280x960 and then by a 2x2 binning, or is
there a 4x4 binning mode. I presume this is correct though, as this has been
validated by many people.

>
> +	/*
> +	 * The compose rectangle models binning, its size is the sensor output
> +	 * size.
> +	 */
> +	compose = v4l2_subdev_state_get_compose(state, IMX219_PAD_IMAGE);
> +	compose->left = 0;
> +	compose->top = 0;
> +	compose->width = fmt->format.width;
> +	compose->height = fmt->format.height;
> +
> +	/*
> +	 * No mode use digital crop, the source pad crop rectangle size and
> +	 * format are thus identical to the image pad compose rectangle.
> +	 */
> +	crop = v4l2_subdev_state_get_crop(state, IMX219_PAD_SOURCE);
> +	crop->left = 0;
> +	crop->top = 0;
> +	crop->width = fmt->format.width;
> +	crop->height = fmt->format.height;
> +
> +	format = v4l2_subdev_state_get_format(state, IMX219_PAD_SOURCE);
> +	*format = fmt->format;
> +
>  	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
>  		int exposure_max;
>  		int exposure_def;
> @@ -874,13 +939,13 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
>  				struct v4l2_subdev_state *state,
>  				struct v4l2_subdev_selection *sel)
>  {
> -	switch (sel->target) {
> -	case V4L2_SEL_TGT_CROP: {
> -		sel->r = *v4l2_subdev_state_get_crop(state, 0);
> -		return 0;
> -	}
> +	struct v4l2_rect *compose;
>
> +	switch (sel->target) {
>  	case V4L2_SEL_TGT_NATIVE_SIZE:
> +		if (sel->pad != IMX219_PAD_IMAGE)
> +			return -EINVAL;
> +
>  		sel->r.top = 0;
>  		sel->r.left = 0;
>  		sel->r.width = IMX219_NATIVE_WIDTH;
> @@ -890,11 +955,35 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
>
>  	case V4L2_SEL_TGT_CROP_DEFAULT:
>  	case V4L2_SEL_TGT_CROP_BOUNDS:
> -		sel->r.top = IMX219_PIXEL_ARRAY_TOP;
> -		sel->r.left = IMX219_PIXEL_ARRAY_LEFT;
> -		sel->r.width = IMX219_PIXEL_ARRAY_WIDTH;
> -		sel->r.height = IMX219_PIXEL_ARRAY_HEIGHT;
> +		switch (sel->pad) {
> +		case IMX219_PAD_IMAGE:
> +			sel->r.top = IMX219_PIXEL_ARRAY_TOP;
> +			sel->r.left = IMX219_PIXEL_ARRAY_LEFT;
> +			sel->r.width = IMX219_PIXEL_ARRAY_WIDTH;
> +			sel->r.height = IMX219_PIXEL_ARRAY_HEIGHT;
> +			return 0;
>
> +		case IMX219_PAD_SOURCE:
> +			compose = v4l2_subdev_state_get_compose(state,
> +								IMX219_PAD_IMAGE);
> +			sel->r.top = 0;
> +			sel->r.left = 0;
> +			sel->r.width = compose->width;
> +			sel->r.height = compose->height;
> +			return 0;
> +		}
> +
> +		break;
> +
> +	case V4L2_SEL_TGT_CROP:
> +		sel->r = *v4l2_subdev_state_get_crop(state, sel->pad);
> +		return 0;
> +
> +	case V4L2_SEL_TGT_COMPOSE:
> +		if (sel->pad != IMX219_PAD_IMAGE)
> +			return -EINVAL;
> +
> +		sel->r = *v4l2_subdev_state_get_compose(state, sel->pad);
>  		return 0;

Do we need to support TGT_COMPOSE_BOUNDS for PAD_IMAGE ? I would have
suggested V4L2_SEL_TGT_COMPOSE_DEFAULT too, but according to the spec
it does not apply to subdevices.

>  	}
>
> @@ -906,7 +995,7 @@ static int imx219_init_state(struct v4l2_subdev *sd,
>  {
>  	struct v4l2_subdev_format fmt = {
>  		.which = V4L2_SUBDEV_FORMAT_TRY,
> -		.pad = 0,
> +		.pad = IMX219_PAD_SOURCE,
>  		.format = {
>  			.code = MEDIA_BUS_FMT_SRGGB10_1X10,
>  			.width = supported_modes[0].width,

Why not intialize pad#1 format here an never touch it again ? Should
also the pad#1 crop and compose rectangles and pad#0 crop be
initialized here ?

> @@ -1174,10 +1263,18 @@ static int imx219_probe(struct i2c_client *client)
>  			    V4L2_SUBDEV_FL_HAS_EVENTS;
>  	imx219->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
>
> -	/* Initialize source pad */
> -	imx219->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	/*
> +	 * Initialize the pads. To preserve backward compatibility with
> +	 * userspace that used the sensor before the introduction of the
> +	 * internal image pad, the external source pad is numbered 0 and the
> +	 * internal image pad numbered 1.
> +	 */
> +	imx219->pads[IMX219_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
> +	imx219->pads[IMX219_PAD_IMAGE].flags = MEDIA_PAD_FL_SINK
> +					     | MEDIA_PAD_FL_INTERNAL;
>
> -	ret = media_entity_pads_init(&imx219->sd.entity, 1, &imx219->pad);
> +	ret = media_entity_pads_init(&imx219->sd.entity,
> +				     ARRAY_SIZE(imx219->pads), imx219->pads);
>  	if (ret) {
>  		dev_err(dev, "failed to init entity pads: %d\n", ret);
>  		goto error_handler_free;
> --
> Regards,
>
> Laurent Pinchart
>
>