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Date:   Tue, 10 Mar 2020 12:01:43 +0200
From:   Sakari Ailus <sakari.ailus@linux.intel.com>
To:     Lad Prabhakar <prabhakar.csengg@gmail.com>
Cc:     Dave Stevenson <dave.stevenson@raspberrypi.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH v2 2/3] media: i2c: imx219: Add support for RAW8 bit
 bayer format
Message-ID: <20200310100143.GB5379@paasikivi.fi.intel.com>
References: <20200306103246.22213-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20200306103246.22213-3-prabhakar.mahadev-lad.rj@bp.renesas.com>
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Hi Prabhakar,

On Fri, Mar 06, 2020 at 10:32:45AM +0000, Lad Prabhakar wrote:
> IMX219 sensor is capable for RAW8/RAW10 modes. This commit adds support
> for RAW8 bayer format.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> ---
>  drivers/media/i2c/imx219.c | 161 +++++++++++++++++++++++++++++--------
>  1 file changed, 127 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index 16010ca1781a..f96f3ce9fd85 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -90,6 +90,11 @@
>  
>  #define IMX219_REG_ORIENTATION		0x0172
>  
> +#define IMX219_CSI_DATA_FORMAT_A_0_7	0x018c
> +#define IMX219_CSI_DATA_FORMAT_A_8_15	0x018d
> +
> +#define IMX219_OPPXCK_DIV		0x0309
> +
>  /* Test Pattern Control */
>  #define IMX219_REG_TEST_PATTERN		0x0600
>  #define IMX219_TEST_PATTERN_DISABLE	0
> @@ -168,15 +173,12 @@ static const struct imx219_reg mode_3280x2464_regs[] = {
>  	{0x0171, 0x01},
>  	{0x0174, 0x00},
>  	{0x0175, 0x00},
> -	{0x018c, 0x0a},
> -	{0x018d, 0x0a},
>  	{0x0301, 0x05},
>  	{0x0303, 0x01},
>  	{0x0304, 0x03},
>  	{0x0305, 0x03},
>  	{0x0306, 0x00},
>  	{0x0307, 0x39},
> -	{0x0309, 0x0a},
>  	{0x030b, 0x01},
>  	{0x030c, 0x00},
>  	{0x030d, 0x72},
> @@ -230,15 +232,12 @@ static const struct imx219_reg mode_1920_1080_regs[] = {
>  	{0x0171, 0x01},
>  	{0x0174, 0x00},
>  	{0x0175, 0x00},
> -	{0x018c, 0x0a},
> -	{0x018d, 0x0a},
>  	{0x0301, 0x05},
>  	{0x0303, 0x01},
>  	{0x0304, 0x03},
>  	{0x0305, 0x03},
>  	{0x0306, 0x00},
>  	{0x0307, 0x39},
> -	{0x0309, 0x0a},
>  	{0x030b, 0x01},
>  	{0x030c, 0x00},
>  	{0x030d, 0x72},
> @@ -290,15 +289,12 @@ static const struct imx219_reg mode_1640_1232_regs[] = {
>  	{0x0171, 0x01},
>  	{0x0174, 0x01},
>  	{0x0175, 0x01},
> -	{0x018c, 0x0a},
> -	{0x018d, 0x0a},
>  	{0x0301, 0x05},
>  	{0x0303, 0x01},
>  	{0x0304, 0x03},
>  	{0x0305, 0x03},
>  	{0x0306, 0x00},
>  	{0x0307, 0x39},
> -	{0x0309, 0x0a},
>  	{0x030b, 0x01},
>  	{0x030c, 0x00},
>  	{0x030d, 0x72},
> @@ -348,6 +344,27 @@ static const char * const imx219_supply_name[] = {
>  
>  #define IMX219_NUM_SUPPLIES ARRAY_SIZE(imx219_supply_name)
>  
> +/*
> + * The supported formats.
> + * This table MUST contain 4 entries per format, to cover the various flip
> + * combinations in the order
> + * - no flip
> + * - h flip
> + * - v flip
> + * - h&v flips
> + */
> +static const u32 codes[] = {
> +	MEDIA_BUS_FMT_SRGGB10_1X10,
> +	MEDIA_BUS_FMT_SGRBG10_1X10,
> +	MEDIA_BUS_FMT_SGBRG10_1X10,
> +	MEDIA_BUS_FMT_SBGGR10_1X10,
> +
> +	MEDIA_BUS_FMT_SRGGB8_1X8,
> +	MEDIA_BUS_FMT_SGRBG8_1X8,
> +	MEDIA_BUS_FMT_SGBRG8_1X8,
> +	MEDIA_BUS_FMT_SBGGR8_1X8,
> +};
> +
>  /*
>   * Initialisation delay between XCLR low->high and the moment when the sensor
>   * can start capture (i.e. can leave software stanby) must be not less than:
> @@ -413,6 +430,8 @@ struct imx219 {
>  	struct v4l2_subdev sd;
>  	struct media_pad pad;
>  
> +	struct v4l2_mbus_framefmt fmt;
> +
>  	struct clk *xclk; /* system clock to IMX219 */
>  	u32 xclk_freq;
>  
> @@ -519,34 +538,57 @@ static int imx219_write_regs(struct imx219 *imx219,
>  }
>  
>  /* Get bayer order based on flip setting. */
> -static u32 imx219_get_format_code(struct imx219 *imx219)
> +static u32 imx219_get_format_code(struct imx219 *imx219, u32 code)
>  {
> -	/*
> -	 * Only one bayer order is supported.
> -	 * It depends on the flip settings.
> -	 */
> -	static const u32 codes[2][2] = {
> -		{ MEDIA_BUS_FMT_SRGGB10_1X10, MEDIA_BUS_FMT_SGRBG10_1X10, },
> -		{ MEDIA_BUS_FMT_SGBRG10_1X10, MEDIA_BUS_FMT_SBGGR10_1X10, },
> -	};
> +	int i;

unsigned int

>  
>  	lockdep_assert_held(&imx219->mutex);
> -	return codes[imx219->vflip->val][imx219->hflip->val];
> +
> +	for (i = 0; i < ARRAY_SIZE(codes); i++)
> +		if (codes[i] == code)
> +			break;
> +
> +	if (i >= ARRAY_SIZE(codes))
> +		i = 0;
> +
> +	i = (i & ~3) | (imx219->vflip->val ? 2 : 0) |
> +	    (imx219->hflip->val ? 1 : 0);
> +
> +	return codes[i];
> +}
> +
> +static void imx219_set_default_format(struct imx219 *imx219)
> +{
> +	struct v4l2_mbus_framefmt *fmt;
> +
> +	mutex_lock(&imx219->mutex);

No mutex needed; all this information is static, and you're calling the
function from probe before any driver's external APIs are accessible.

> +
> +	fmt = &imx219->fmt;
> +	fmt->code = MEDIA_BUS_FMT_SRGGB10_1X10;
> +	fmt->colorspace = V4L2_COLORSPACE_SRGB;
> +	fmt->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(fmt->colorspace);
> +	fmt->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true,
> +							  fmt->colorspace,
> +							  fmt->ycbcr_enc);
> +	fmt->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(fmt->colorspace);
> +	fmt->width = supported_modes[0].width;
> +	fmt->height = supported_modes[0].height;
> +	fmt->field = V4L2_FIELD_NONE;
> +
> +	mutex_unlock(&imx219->mutex);
>  }
>  
>  static int imx219_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
>  {
>  	struct imx219 *imx219 = to_imx219(sd);
> +	struct v4l2_mbus_framefmt *cur_fmt = &imx219->fmt;
>  	struct v4l2_mbus_framefmt *try_fmt =
>  		v4l2_subdev_get_try_format(sd, fh->pad, 0);
>  
>  	mutex_lock(&imx219->mutex);
>  
>  	/* Initialize try_fmt */
> -	try_fmt->width = supported_modes[0].width;
> -	try_fmt->height = supported_modes[0].height;
> -	try_fmt->code = imx219_get_format_code(imx219);
> -	try_fmt->field = V4L2_FIELD_NONE;
> +	try_fmt = cur_fmt;

The default try format should reflect the device default, not current
format. Although the pixel order needs to be taken into account, as was
already done.

>  
>  	mutex_unlock(&imx219->mutex);
>  
> @@ -648,14 +690,12 @@ static int imx219_enum_mbus_code(struct v4l2_subdev *sd,
>  {
>  	struct imx219 *imx219 = to_imx219(sd);
>  
> -	/*
> -	 * Only one bayer order is supported (though it depends on the flip
> -	 * settings)
> -	 */
> -	if (code->index > 0)
> +	if (code->pad != 0)
> +		return -EINVAL;

The pad is already checked by the caller, no need to repeat here.

> +	if (code->index >= (ARRAY_SIZE(codes) / 4))
>  		return -EINVAL;
>  
> -	code->code = imx219_get_format_code(imx219);
> +	code->code = imx219_get_format_code(imx219, codes[code->index * 4]);
>  
>  	return 0;
>  }
> @@ -669,7 +709,7 @@ static int imx219_enum_frame_size(struct v4l2_subdev *sd,
>  	if (fse->index >= ARRAY_SIZE(supported_modes))
>  		return -EINVAL;
>  
> -	if (fse->code != imx219_get_format_code(imx219))
> +	if (fse->code != imx219_get_format_code(imx219, imx219->fmt.code))
>  		return -EINVAL;
>  
>  	fse->min_width = supported_modes[fse->index].width;
> @@ -696,7 +736,6 @@ static void imx219_update_pad_format(struct imx219 *imx219,
>  {
>  	fmt->format.width = mode->width;
>  	fmt->format.height = mode->height;
> -	fmt->format.code = imx219_get_format_code(imx219);
>  	fmt->format.field = V4L2_FIELD_NONE;
>  
>  	imx219_reset_colorspace(&fmt->format);
> @@ -710,10 +749,12 @@ static int __imx219_get_pad_format(struct imx219 *imx219,
>  		struct v4l2_mbus_framefmt *try_fmt =
>  			v4l2_subdev_get_try_format(&imx219->sd, cfg, fmt->pad);
>  		/* update the code which could change due to vflip or hflip: */
> -		try_fmt->code = imx219_get_format_code(imx219);
> +		try_fmt->code = imx219_get_format_code(imx219, try_fmt->code);
>  		fmt->format = *try_fmt;
>  	} else {
>  		imx219_update_pad_format(imx219, imx219->mode, fmt);
> +		fmt->format.code = imx219_get_format_code(imx219,
> +							  imx219->fmt.code);
>  	}
>  
>  	return 0;
> @@ -741,11 +782,18 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>  	const struct imx219_mode *mode;
>  	struct v4l2_mbus_framefmt *framefmt;
>  	int exposure_max, exposure_def, hblank;
> +	int i;

unsigned int

>  
>  	mutex_lock(&imx219->mutex);
>  
> +	for (i = 0; i < ARRAY_SIZE(codes); i++)
> +		if (codes[i] == fmt->format.code)
> +			break;
> +	if (i >= ARRAY_SIZE(codes))
> +		i = 0;
> +
>  	/* Bayer order varies with flips */
> -	fmt->format.code = imx219_get_format_code(imx219);
> +	fmt->format.code = imx219_get_format_code(imx219, codes[i]);
>  
>  	mode = v4l2_find_nearest_size(supported_modes,
>  				      ARRAY_SIZE(supported_modes),
> @@ -755,7 +803,9 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>  	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
>  		framefmt = v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
>  		*framefmt = fmt->format;
> -	} else if (imx219->mode != mode) {
> +	} else if (imx219->mode != mode ||
> +		   imx219->fmt.code != fmt->format.code) {
> +		imx219->fmt = fmt->format;
>  		imx219->mode = mode;
>  		/* Update limits and set FPS to default */
>  		__v4l2_ctrl_modify_range(imx219->vblank, IMX219_VBLANK_MIN,
> @@ -786,6 +836,40 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
>  	return 0;
>  }
>  
> +static int imx219_set_framefmt(struct imx219 *imx219)
> +{
> +	int ret;
> +
> +	switch (imx219->fmt.code) {
> +	case MEDIA_BUS_FMT_SRGGB8_1X8:
> +	case MEDIA_BUS_FMT_SGRBG8_1X8:
> +	case MEDIA_BUS_FMT_SGBRG8_1X8:
> +	case MEDIA_BUS_FMT_SBGGR8_1X8:
> +		ret = imx219_write_reg(imx219, IMX219_CSI_DATA_FORMAT_A_0_7,
> +				       IMX219_REG_VALUE_08BIT, 0x08);
> +		ret |= imx219_write_reg(imx219, IMX219_CSI_DATA_FORMAT_A_8_15,
> +				       IMX219_REG_VALUE_08BIT, 0x08);
> +		ret |= imx219_write_reg(imx219, IMX219_OPPXCK_DIV,
> +					IMX219_REG_VALUE_08BIT, 0x08);

What kind of error codes do you expect to get? :-)

Please either return the error immediately, or check ret before the
assignment.

> +		break;
> +	case MEDIA_BUS_FMT_SRGGB10_1X10:
> +	case MEDIA_BUS_FMT_SGRBG10_1X10:
> +	case MEDIA_BUS_FMT_SGBRG10_1X10:
> +	case MEDIA_BUS_FMT_SBGGR10_1X10:
> +		ret = imx219_write_reg(imx219, IMX219_CSI_DATA_FORMAT_A_0_7,
> +				       IMX219_REG_VALUE_08BIT, 0x0a);
> +		ret |= imx219_write_reg(imx219, IMX219_CSI_DATA_FORMAT_A_8_15,
> +				       IMX219_REG_VALUE_08BIT, 0x0a);
> +		ret |= imx219_write_reg(imx219, IMX219_OPPXCK_DIV,
> +					IMX219_REG_VALUE_08BIT, 0x0a);
> +		break;
> +	default:
> +		ret = -EINVAL;

You could return -EINVAL here.

> +	}
> +
> +	return ret;
> +}
> +
>  static int imx219_start_streaming(struct imx219 *imx219)
>  {
>  	struct i2c_client *client = v4l2_get_subdevdata(&imx219->sd);
> @@ -800,6 +884,12 @@ static int imx219_start_streaming(struct imx219 *imx219)
>  		return ret;
>  	}
>  
> +	ret = imx219_set_framefmt(imx219);
> +	if (ret) {
> +		dev_err(&client->dev, "%s failed to set format\n", __func__);

The error code could be useful.

> +		return ret;
> +	}
> +
>  	/* Apply customized values from user */
>  	ret =  __v4l2_ctrl_handler_setup(imx219->sd.ctrl_handler);
>  	if (ret)
> @@ -1253,6 +1343,9 @@ static int imx219_probe(struct i2c_client *client)
>  	/* Initialize source pad */
>  	imx219->pad.flags = MEDIA_PAD_FL_SOURCE;
>  
> +	/* Initialize default format */
> +	imx219_set_default_format(imx219);
> +
>  	ret = media_entity_pads_init(&imx219->sd.entity, 1, &imx219->pad);
>  	if (ret) {
>  		dev_err(dev, "failed to init entity pads: %d\n", ret);

-- 
Kind regards,

Sakari Ailus