Re: [PATCH v7 02/15] media: i2c: imx219: Add internal image sink pad

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Mar 27, 2024 at 11:51:49AM +0200, Tomi Valkeinen wrote:
> On 25/03/2024 00:08, 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.
> 
> If I remember right, we discussed that this (internal pads after 
> external pads) would be the approach also for totally new drivers.

Do you recall the rationale for that ? Compatibility (within some limits
I suppose) with existing userspace for new drivers ?

> > 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,
> > +	IMX219_NUM_PADS,
> > +};
> 
> Nitpick, but if the numbering of the values is important, I always mark 
> the first one "= 0", to make it clear(er) for the reader.

I'll do that.

> >   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;
> > +	} 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;
> > +	format->code = IMX219_NATIVE_FORMAT;
> > +	format->width = IMX219_NATIVE_WIDTH;
> > +	format->height = IMX219_NATIVE_HEIGHT;
> 
> Isn't the image pad format always the same, and cannot be changed? The 
> above hints otherwise. What fields can change in the image pad?

None. I'll update the comment above to state

	/* The image pad models the pixel array, and thus has a fixed format. */

The code behaviour matches that.

> >   	/*
> >   	 * 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;
> >   
> > +	/*
> > +	 * 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;
> >   	}
> >   
> > @@ -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,
> > @@ -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