media: imx283: Provide optical black mode

The IMX283 is capable of delivering optical black regions as part of
the image capture. These regions support capture of the black levels
for calibration and are added as extra pixels on top of the full
resolution capture.

Supply an extra mode which accounts for this increased size that will
produce black regions in the output image.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
- YUYV capture sample with Pi5 ISP for side-by-side comparison of OB regions:
https://gcdnb.pbrd.co/images/XQV29MedwXxg.png
---
 drivers/media/i2c/imx283.c | 68 ++++++++++++++++++++++++++++++++------
 1 file changed, 58 insertions(+), 10 deletions(-)

Hi Umang,

Thank you for the patch.

On Tue, Jul 30, 2024 at 12:09:53AM +0530, Umang Jain wrote:
> The IMX283 is capable of delivering optical black regions as part of
> the image capture. These regions support capture of the black levels
> for calibration and are added as extra pixels on top of the full
> resolution capture.
> 
> Supply an extra mode which accounts for this increased size that will
> produce black regions in the output image.

Sorry, but this shouldn't be an extra mode. We need a proper API, you
need to convert the driver to make it freely configurable. Furthermore,
the OB stream should probably be reported by .get_frame_desc().

> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> ---
> - YUYV capture sample with Pi5 ISP for side-by-side comparison of OB regions:
> https://gcdnb.pbrd.co/images/XQV29MedwXxg.png
> ---
>  drivers/media/i2c/imx283.c | 68 ++++++++++++++++++++++++++++++++------
>  1 file changed, 58 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx283.c b/drivers/media/i2c/imx283.c
> index 8490618c5071..9a0fe2c34a41 100644
> --- a/drivers/media/i2c/imx283.c
> +++ b/drivers/media/i2c/imx283.c
> @@ -66,6 +66,7 @@
>  #define IMX283_REG_HTRIMMING		CCI_REG8(0x300b)
>  #define   IMX283_MDVREV			BIT(0) /* VFLIP */
>  #define   IMX283_HTRIMMING_EN		BIT(4)
> +#define   IMX283_HOB_EN			BIT(5)
>  
>  #define IMX283_REG_VWINPOS		CCI_REG16_LE(0x300f)
>  #define IMX283_REG_VWIDCUT		CCI_REG16_LE(0x3011)
> @@ -306,6 +307,7 @@ static const struct imx283_input_frequency imx283_frequencies[] = {
>  
>  enum imx283_modes {
>  	IMX283_MODE_0,
> +	IMX283_MODE_0_OB,
>  	IMX283_MODE_1,
>  	IMX283_MODE_1A,
>  	IMX283_MODE_1S,
> @@ -327,6 +329,7 @@ struct imx283_readout_mode {
>  static const struct imx283_readout_mode imx283_readout_modes[] = {
>  	/* All pixel scan modes */
>  	[IMX283_MODE_0] = { 0x04, 0x03, 0x10, 0x00 }, /* 12 bit */
> +	[IMX283_MODE_0_OB] = { 0x04, 0x03, 0x10, 0x00 }, /* 12 bit */
>  	[IMX283_MODE_1] = { 0x04, 0x01, 0x00, 0x00 }, /* 10 bit */
>  	[IMX283_MODE_1A] = { 0x04, 0x01, 0x20, 0x50 }, /* 10 bit */
>  	[IMX283_MODE_1S] = { 0x04, 0x41, 0x20, 0x50 }, /* 10 bit */
> @@ -439,6 +442,36 @@ static const struct imx283_mode supported_modes_12bit[] = {
>  			.height = 3648,
>  		},
>  	},
> +	{
> +		/* 20MPix 21.40 fps readout mode 0 with optical blacks enabled */
> +		.mode = IMX283_MODE_0_OB,
> +		.bpp = 12,
> +		.width = 5472 + 96, /* width + Horizontal optical black */
> +		.height = 3648 + 16, /* height + Vertical optical black */
> +		.min_hmax = 5914, /* 887 @ 480MHz/72MHz */
> +		.min_vmax = 3793, /* Lines */
> +
> +		.veff = 3694,
> +		.vst = 0,
> +		.vct = 0,
> +
> +		.hbin_ratio = 1,
> +		.vbin_ratio = 1,
> +
> +		/* 20.00 FPS */
> +		.default_hmax = 6000, /* 900 @ 480MHz/72MHz */
> +		.default_vmax = 4000,
> +
> +		.min_shr = 11,
> +		.horizontal_ob = 96,
> +		.vertical_ob = 16,
> +		.crop = {
> +			.top = 40,
> +			.left = 108,
> +			.width = 5472 + 96,
> +			.height = 3648 + 16,
> +		},
> +	},
>  	{
>  		/*
>  		 * Readout mode 2 : 2/2 binned mode (2736x1824)
> @@ -793,17 +826,20 @@ static int imx283_set_ctrl(struct v4l2_ctrl *ctrl)
>  		break;
>  
>  	case V4L2_CID_VFLIP:
> +		u32 htrim = IMX283_HTRIMMING_EN;
> +
>  		/*
>  		 * VFLIP is managed by BIT(0) of IMX283_REG_HTRIMMING address, hence
>  		 * both need to be set simultaneously.
>  		 */
> -		if (ctrl->val) {
> -			cci_write(imx283->cci, IMX283_REG_HTRIMMING,
> -				  IMX283_HTRIMMING_EN | IMX283_MDVREV, &ret);
> -		} else {
> -			cci_write(imx283->cci, IMX283_REG_HTRIMMING,
> -				  IMX283_HTRIMMING_EN, &ret);
> -		}
> +		if (ctrl->val)
> +			htrim = IMX283_HTRIMMING_EN | IMX283_MDVREV;
> +
> +		if (mode->mode == IMX283_MODE_0_OB)
> +			htrim |= IMX283_HOB_EN;
> +
> +		cci_write(imx283->cci, IMX283_REG_HTRIMMING, htrim, &ret);
> +
>  		break;
>  
>  	case V4L2_CID_TEST_PATTERN:
> @@ -1010,6 +1046,8 @@ static int imx283_start_streaming(struct imx283 *imx283,
>  	s32 v_pos;
>  	u32 write_v_size;
>  	u32 y_out_size;
> +	u32 htrim_end;
> +	u32 ob_size_v = 0;
>  	int ret = 0;
>  
>  	fmt = v4l2_subdev_state_get_format(state, 0);
> @@ -1057,6 +1095,12 @@ static int imx283_start_streaming(struct imx283 *imx283,
>  		mode->crop.height);
>  
>  	y_out_size = mode->crop.height / mode->vbin_ratio;
> +
> +	if (mode->mode == IMX283_MODE_0_OB) {
> +		y_out_size -= mode->vertical_ob;
> +		ob_size_v = mode->vertical_ob;
> +	}
> +
>  	write_v_size = y_out_size + mode->vertical_ob;
>  	/*
>  	 * cropping start position = (VWINPOS – Vst) × 2
> @@ -1072,12 +1116,16 @@ static int imx283_start_streaming(struct imx283 *imx283,
>  	cci_write(imx283->cci, IMX283_REG_VWIDCUT, v_widcut, &ret);
>  	cci_write(imx283->cci, IMX283_REG_VWINPOS, v_pos, &ret);
>  
> -	cci_write(imx283->cci, IMX283_REG_OB_SIZE_V, mode->vertical_ob, &ret);
> +	cci_write(imx283->cci, IMX283_REG_OB_SIZE_V, ob_size_v, &ret);
> +
> +	htrim_end = mode->crop.left + mode->crop.width;
> +
> +	if (mode->mode == IMX283_MODE_0_OB)
> +		htrim_end -= mode->horizontal_ob * mode->hbin_ratio;
>  
>  	/* TODO: Validate mode->crop is fully contained within imx283_native_area */
>  	cci_write(imx283->cci, IMX283_REG_HTRIMMING_START, mode->crop.left, &ret);
> -	cci_write(imx283->cci, IMX283_REG_HTRIMMING_END,
> -		  mode->crop.left + mode->crop.width, &ret);
> +	cci_write(imx283->cci, IMX283_REG_HTRIMMING_END, htrim_end, &ret);
>  
>  	/* Disable embedded data */
>  	cci_write(imx283->cci, IMX283_REG_EBD_X_OUT_SIZE, 0, &ret);