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Date: Mon, 8 Jan 2024 10:19:35 +0100
From: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>, 
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Vinay Varma <varmavinaym@gmail.com>, 
	Dave Stevenson <dave.stevenson@raspberrypi.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, 
	"open list:SONY IMX219 SENSOR DRIVER" <linux-media@vger.kernel.org>, open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] media: i2c: imx219: implement the v4l2 selection api
Message-ID: <3q6andka2su7i43xz2ok44ejvtb3hdjdn6xretyde7sdcvtd7l@lz2syngckivi>
References: <kv6yfyahbud474e75y4jaczg64pcowvlz7i52kikknuh6wje5o@4k2hikwcueoy>
 <ZZu2C_lu6TAh-LOf@kekkonen.localdomain>
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In-Reply-To: <ZZu2C_lu6TAh-LOf@kekkonen.localdomain>

Hi Sakari, Vinay,

   a more foundamental question is how this usage of the crop/compose
API plays with the fact we enumerate only a limited set of frame
sizes, and now you can get an arbitrary output size. We could get away
by modifying enum_frame_sizes to return a size range (or ranges) but I
wonder if it wouldn't be better to introduce an internal pad to
represent the pixel array where to apply TGT_CROP in combination with
a source pad where we could apply TGT_COMPOSE and an output format.

To be completely honest, binning should be handled with a different
mechanism than the selection API, but that would require a completly
new design.

Laurent: are there plans to introduce internal pad for embedded data
support for this sensor ?

Also, the patch doesn't apply on the most recent media master, please
rebase before resending.

On Mon, Jan 08, 2024 at 08:44:59AM +0000, Sakari Ailus wrote:
> Hi Vinay,
>
> Thanks for the patch.
>
> On Sun, Jan 07, 2024 at 03:42:59PM +0800, Vinay Varma wrote:
> > This patch exposes IMX219's crop and compose capabilities
> > by implementing the selection API. Horizontal and vertical
> > binning being separate registers, `imx219_binning_goodness`
> > computes the best possible height and width of the compose
> > specification using the selection flags. Compose operation
> > updates the subdev's format object to keep them in sync.
>
> The line length limit here is 75, not ~ 60. Please rewrap.
>
> >
> > Signed-off-by: Vinay Varma <varmavinaym@gmail.com>
> > ---
> >  drivers/media/i2c/imx219.c | 222 +++++++++++++++++++++++++++++++------
> >  1 file changed, 190 insertions(+), 32 deletions(-)
> >
> > diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> > index 39943d72c22d..27d85fb7ad51 100644
> > --- a/drivers/media/i2c/imx219.c
> > +++ b/drivers/media/i2c/imx219.c
> > @@ -29,6 +29,7 @@
> >  #include <media/v4l2-event.h>
> >  #include <media/v4l2-fwnode.h>
> >  #include <media/v4l2-mediabus.h>
> > +#include <media/v4l2-rect.h>
> >
> >  /* Chip ID */
> >  #define IMX219_REG_CHIP_ID		CCI_REG16(0x0000)
> > @@ -73,6 +74,7 @@
> >  /* V_TIMING internal */
> >  #define IMX219_REG_VTS			CCI_REG16(0x0160)
> >  #define IMX219_VTS_MAX			0xffff
> > +#define IMX219_VTS_DEF 1763
> >
> >  #define IMX219_VBLANK_MIN		32
> >
> > @@ -146,6 +148,7 @@
> >  #define IMX219_PIXEL_ARRAY_TOP		8U
> >  #define IMX219_PIXEL_ARRAY_WIDTH	3280U
> >  #define IMX219_PIXEL_ARRAY_HEIGHT	2464U
> > +#define IMX219_MIN_COMPOSE_SIZE 8U
>
> Please align 8U with the rest of the macros. Same above.
>
> >
> >  /* Mode : resolution and related config&values */
> >  struct imx219_mode {
> > @@ -284,6 +287,8 @@ static const u32 imx219_mbus_formats[] = {
> >  #define IMX219_XCLR_MIN_DELAY_US	6200
> >  #define IMX219_XCLR_DELAY_RANGE_US	1000
> >
> > +static const u32 binning_ratios[] = { 1, 2 };
> > +
> >  /* Mode configs */
> >  static const struct imx219_mode supported_modes[] = {
> >  	{
> > @@ -296,19 +301,19 @@ static const struct imx219_mode supported_modes[] = {
> >  		/* 1080P 30fps cropped */
> >  		.width = 1920,
> >  		.height = 1080,
> > -		.vts_def = 1763,
> > +		.vts_def = IMX219_VTS_DEF,
> >  	},
> >  	{
> >  		/* 2x2 binned 30fps mode */
> >  		.width = 1640,
> >  		.height = 1232,
> > -		.vts_def = 1763,
> > +		.vts_def = IMX219_VTS_DEF,
> >  	},
> >  	{
> >  		/* 640x480 30fps mode */
> >  		.width = 640,
> >  		.height = 480,
> > -		.vts_def = 1763,
> > +		.vts_def = IMX219_VTS_DEF,
> >  	},
> >  };
> >
> > @@ -809,6 +814,39 @@ static int imx219_enum_frame_size(struct v4l2_subdev *sd,
> >  	return 0;
> >  }
> >
> > +static void imx219_refresh_ctrls(struct v4l2_subdev *sd,
> > +				 struct v4l2_subdev_state *state,
> > +				 unsigned int vts_def)
> > +{
> > +	int exposure_max;
> > +	int exposure_def;
> > +	int hblank;
> > +	struct imx219 *imx219 = to_imx219(sd);
> > +	struct v4l2_mbus_framefmt *fmt =
> > +		v4l2_subdev_get_pad_format(sd, state, 0);
> > +
> > +	/* Update limits and set FPS to default */
> > +	__v4l2_ctrl_modify_range(imx219->vblank, IMX219_VBLANK_MIN,
> > +				 IMX219_VTS_MAX - fmt->height, 1,
> > +				 vts_def - fmt->height);
> > +	__v4l2_ctrl_s_ctrl(imx219->vblank, vts_def - fmt->height);
> > +	/* Update max exposure while meeting expected vblanking */
> > +	exposure_max = vts_def - 4;
> > +	exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
> > +			       exposure_max :
> > +			       IMX219_EXPOSURE_DEFAULT;
> > +	__v4l2_ctrl_modify_range(imx219->exposure, imx219->exposure->minimum,
> > +				 exposure_max, imx219->exposure->step,
> > +				 exposure_def);
> > +	/*
> > +	 * Currently PPL is fixed to IMX219_PPL_DEFAULT, so hblank
> > +	 * depends on mode->width only, and is not changeble in any
> > +	 * way other than changing the mode.
> > +	 */
> > +	hblank = IMX219_PPL_DEFAULT - fmt->width;
> > +	__v4l2_ctrl_modify_range(imx219->hblank, hblank, hblank, 1, hblank);
> > +}
> > +
> >  static int imx219_set_pad_format(struct v4l2_subdev *sd,
> >  				 struct v4l2_subdev_state *state,
> >  				 struct v4l2_subdev_format *fmt)
> > @@ -816,7 +854,7 @@ 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 *crop;
> > +	struct v4l2_rect *crop, *compose;
> >  	unsigned int bin_h, bin_v;
> >
> >  	mode = v4l2_find_nearest_size(supported_modes,
> > @@ -842,34 +880,14 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
> >  	crop->left = (IMX219_NATIVE_WIDTH - crop->width) / 2;
> >  	crop->top = (IMX219_NATIVE_HEIGHT - crop->height) / 2;
> >
> > -	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> > -		int exposure_max;
> > -		int exposure_def;
> > -		int hblank;
> > -
> > -		/* Update limits and set FPS to default */
> > -		__v4l2_ctrl_modify_range(imx219->vblank, IMX219_VBLANK_MIN,
> > -					 IMX219_VTS_MAX - mode->height, 1,
> > -					 mode->vts_def - mode->height);
> > -		__v4l2_ctrl_s_ctrl(imx219->vblank,
> > -				   mode->vts_def - mode->height);
> > -		/* Update max exposure while meeting expected vblanking */
> > -		exposure_max = mode->vts_def - 4;
> > -		exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
> > -			exposure_max : IMX219_EXPOSURE_DEFAULT;
> > -		__v4l2_ctrl_modify_range(imx219->exposure,
> > -					 imx219->exposure->minimum,
> > -					 exposure_max, imx219->exposure->step,
> > -					 exposure_def);
> > -		/*
> > -		 * Currently PPL is fixed to IMX219_PPL_DEFAULT, so hblank
> > -		 * depends on mode->width only, and is not changeble in any
> > -		 * way other than changing the mode.
> > -		 */
> > -		hblank = IMX219_PPL_DEFAULT - mode->width;
> > -		__v4l2_ctrl_modify_range(imx219->hblank, hblank, hblank, 1,
> > -					 hblank);
> > -	}
> > +	compose = v4l2_subdev_get_pad_compose(sd, state, 0);
> > +	compose->width = format->width;
> > +	compose->height = format->height;
> > +	compose->left = 0;
> > +	compose->top = 0;
> > +
> > +	if (fmt->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > +		imx219_refresh_ctrls(sd, state, mode->vts_def);
> >
> >  	return 0;
> >  }
> > @@ -884,6 +902,11 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
> >  		return 0;
> >  	}
> >
> > +	case V4L2_SEL_TGT_COMPOSE: {
> > +		sel->r = *v4l2_subdev_get_pad_compose(sd, state, 0);
> > +		return 0;
> > +	}
>
> The braces are unnecessary here.
>
> > +
> >  	case V4L2_SEL_TGT_NATIVE_SIZE:
> >  		sel->r.top = 0;
> >  		sel->r.left = 0;
> > @@ -900,11 +923,145 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
> >  		sel->r.height = IMX219_PIXEL_ARRAY_HEIGHT;
> >
> >  		return 0;
> > +
> > +	case V4L2_SEL_TGT_COMPOSE_DEFAULT:
> > +	case V4L2_SEL_TGT_COMPOSE_BOUNDS:
> > +	case V4L2_SEL_TGT_COMPOSE_PADDED:
> > +		sel->r.top = 0;
> > +		sel->r.left = 0;
> > +		sel->r.width = IMX219_PIXEL_ARRAY_WIDTH;
> > +		sel->r.height = IMX219_PIXEL_ARRAY_HEIGHT;
> > +		return 0;
> >  	}
> >
> >  	return -EINVAL;
> >  }
> >
> > +#define IMX219_ROUND(dim, step, flags)                \
> > +	((flags) & V4L2_SEL_FLAG_GE ?                 \
> > +		 round_up((dim), (step)) :            \
> > +		 ((flags) & V4L2_SEL_FLAG_LE ?        \
> > +			  round_down((dim), (step)) : \
> > +			  round_down((dim) + (step) / 2, (step))))
> > +
> > +static int imx219_set_selection_crop(struct v4l2_subdev *sd,
> > +				     struct v4l2_subdev_state *sd_state,
> > +				     struct v4l2_subdev_selection *sel)
> > +{
> > +	u32 max_binning;
> > +	struct v4l2_rect *compose, *crop;
> > +	struct v4l2_mbus_framefmt *fmt;
> > +
> > +	crop = v4l2_subdev_get_pad_crop(sd, sd_state, 0);
> > +	if (v4l2_rect_equal(&sel->r, crop))
> > +		return false;
> > +	max_binning = binning_ratios[ARRAY_SIZE(binning_ratios) - 1];
> > +	sel->r.width =
> > +		clamp(IMX219_ROUND(sel->r.width, max_binning, sel->flags),
> > +		      max_binning * IMX219_MIN_COMPOSE_SIZE,
> > +		      IMX219_PIXEL_ARRAY_WIDTH);
> > +	sel->r.height =
> > +		clamp(IMX219_ROUND(sel->r.width, max_binning, sel->flags),
> > +		      max_binning * IMX219_MIN_COMPOSE_SIZE,
> > +		      IMX219_PIXEL_ARRAY_WIDTH);
> > +	sel->r.left =
> > +		min_t(u32, sel->r.left, IMX219_PIXEL_ARRAY_LEFT - sel->r.width);
> > +	sel->r.top =
> > +		min_t(u32, sel->r.top, IMX219_PIXEL_ARRAY_TOP - sel->r.top);
> > +
> > +	compose = v4l2_subdev_get_pad_compose(sd, sd_state, 0);
> > +	fmt = v4l2_subdev_get_pad_format(sd, sd_state, 0);
> > +	*crop = sel->r;
> > +	compose->height = crop->height;
> > +	compose->width = crop->width;
> > +	return true;
> > +}
> > +
> > +static int imx219_binning_goodness(u32 act, u32 ask, u32 flags)
> > +{
> > +	const int goodness = 100000;
> > +	int val = 0;
> > +
> > +	if (flags & V4L2_SEL_FLAG_GE)
> > +		if (act < ask)
> > +			val -= goodness;
> > +
> > +	if (flags & V4L2_SEL_FLAG_LE)
> > +		if (act > ask)
> > +			val -= goodness;
> > +
> > +	val -= abs(act - ask);
> > +
> > +	return val;
> > +}
> > +
> > +static bool imx219_set_selection_compose(struct v4l2_subdev *sd,
> > +					 struct v4l2_subdev_state *state,
> > +					 struct v4l2_subdev_selection *sel)
> > +{
> > +	int best_goodness;
>
> This would be nicer if declared after the line below. Think of reverse
> Christmas trees.
>
> Similarly for max_binning a few functions up actually as well as variables
> in imx219_refresh_ctrls().
>
> > +	struct v4l2_rect *compose, *crop;
> > +
> > +	compose = v4l2_subdev_get_pad_compose(sd, state, 0);
> > +	if (v4l2_rect_equal(compose, &sel->r))
> > +		return false;
> > +
> > +	crop = v4l2_subdev_get_pad_crop(sd, state, 0);
> > +
> > +	best_goodness = INT_MIN;
> > +	for (int i = 0; i < ARRAY_SIZE(binning_ratios); ++i) {
> > +		u32 width = crop->width / binning_ratios[i];
> > +		int goodness = imx219_binning_goodness(width, sel->r.width,
> > +						       sel->flags);
> > +		if (goodness > best_goodness) {
> > +			best_goodness = goodness;
> > +			compose->width = width;
> > +		}
> > +	}
> > +	best_goodness = INT_MIN;
> > +	for (int i = 0; i < ARRAY_SIZE(binning_ratios); ++i) {
> > +		u32 height = crop->height / binning_ratios[i];
> > +		int goodness = imx219_binning_goodness(height, sel->r.height,
> > +						       sel->flags);
> > +		if (goodness > best_goodness) {
> > +			best_goodness = goodness;
> > +			compose->height = height;
> > +		}
> > +	}
> > +	return true;
> > +}
> > +
> > +static int imx219_set_selection(struct v4l2_subdev *sd,
> > +				struct v4l2_subdev_state *sd_state,
> > +				struct v4l2_subdev_selection *sel)
> > +{
> > +	bool compose_updated = false;
> > +
> > +	switch (sel->target) {
> > +	case V4L2_SEL_TGT_CROP:
> > +		compose_updated = imx219_set_selection_crop(sd, sd_state, sel);
> > +		break;
> > +	case V4L2_SEL_TGT_COMPOSE:
> > +		compose_updated =
> > +			imx219_set_selection_compose(sd, sd_state, sel);
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +	if (compose_updated) {
> > +		struct v4l2_rect *compose =
> > +			v4l2_subdev_get_pad_compose(sd, sd_state, 0);
> > +		struct v4l2_mbus_framefmt *fmt =
> > +			v4l2_subdev_get_pad_format(sd, sd_state, 0);
>
> A newline here?
>
> > +		fmt->height = compose->height;
> > +		fmt->width = compose->width;
> > +	}
> > +	if (compose_updated && sel->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > +		imx219_refresh_ctrls(sd, sd_state, IMX219_VTS_DEF);
>
> Please move this inside the previous condition (where you check just
> sel->which).
>
> > +
> > +	return 0;
> > +}
> > +
> >  static int imx219_init_cfg(struct v4l2_subdev *sd,
> >  			   struct v4l2_subdev_state *state)
> >  {
> > @@ -938,6 +1095,7 @@ static const struct v4l2_subdev_pad_ops imx219_pad_ops = {
> >  	.get_fmt = v4l2_subdev_get_fmt,
> >  	.set_fmt = imx219_set_pad_format,
> >  	.get_selection = imx219_get_selection,
> > +	.set_selection = imx219_set_selection,
> >  	.enum_frame_size = imx219_enum_frame_size,
> >  };
> >
>
> --
> Regards,
>
> Sakari Ailus
>