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

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

On Thu, Mar 28, 2024 at 06:18:24PM +0200, Tomi Valkeinen wrote:
> On 28/03/2024 18:09, Laurent Pinchart wrote:
> > 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 ?
> 
> I don't. Probably compatibility, and making the subdevs with internal 
> pads look similar to subdevs without them. I guess in theory it 
> shouldn't matter.
> 
> >>> 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.
> 
> If it never changes, shouldn't it be set once in init_state, rather than 
> setting it here every time set_format is called?

I think Sakari commented on that too. It's possible, but make
.init_state() significantly more complex, and splits the logic between
.init_state() and .set_fmt(). I'm not convinced it's worth the work.

-- 
Regards,

Laurent Pinchart