Re: [PATCH v2 2/3] media: i2c: imx219: make HBLANK r/w to allow longer exposures

Jacopo Mondi
2024-11-22T10:22:35Z

Hi Jai

On Thu, Nov 21, 2024 at 05:38:03PM +0530, Jai Luthra wrote:
> From: Dave Stevenson <dave.stevenson@raspberrypi.com>
>
> The HBLANK control was read-only, and always configured such
> that the sensor HTS register was 3448. This limited the maximum
> exposure time that could be achieved to around 1.26 secs.
>
> Make HBLANK read/write so that the line time can be extended,
> and thereby allow longer exposures (and slower frame rates).
> Retain the overall HTS setting when changing modes rather than
> resetting it to a default.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Signed-off-by: Jai Luthra <jai.luthra@ideasonboard.com>
> ---
> drivers/media/i2c/imx219.c | 37 ++++++++++++++++++++++++-------------
> 1 file changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index f98aad74fe584a18e2fe7126f92bf294762a54e3..970e6362d0ae3a9078daf337155e83d637bc1ca1 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -76,8 +76,10 @@
>
> #define IMX219_VBLANK_MIN 32
>
> -/* HBLANK control - read only */
> -#define IMX219_PPL_DEFAULT 3448
> +/* HBLANK control range */
> +#define IMX219_PPL_MIN 0x0d78
> +#define IMX219_PPL_MAX 0x7ff0
> +#define IMX219_REG_HTS CCI_REG16(0x0162)
>
> #define IMX219_REG_LINE_LENGTH_A CCI_REG16(0x0162)
> #define IMX219_REG_X_ADD_STA_A CCI_REG16(0x0164)
> @@ -422,6 +424,10 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
> cci_write(imx219->regmap, IMX219_REG_VTS,
> format->height + ctrl->val, &ret);
> break;
> + case V4L2_CID_HBLANK:
> + cci_write(imx219->regmap, IMX219_REG_HTS,
> + format->width + ctrl->val, &ret);
> + break;
> case V4L2_CID_TEST_PATTERN_RED:
> cci_write(imx219->regmap, IMX219_REG_TESTP_RED,
> ctrl->val, &ret);
> @@ -496,12 +502,10 @@ static int imx219_init_controls(struct imx219 *imx219)
> V4L2_CID_VBLANK, IMX219_VBLANK_MIN,
> IMX219_VTS_MAX - mode->height, 1,
> mode->vts_def - mode->height);
> - hblank = IMX219_PPL_DEFAULT - mode->width;
> + hblank = IMX219_PPL_MIN - mode->width;
> imx219->hblank = v4l2_ctrl_new_std(ctrl_hdlr, &imx219_ctrl_ops,
> V4L2_CID_HBLANK, hblank, hblank,
> 1, hblank);
> - if (imx219->hblank)
> - imx219->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> exposure_max = mode->vts_def - 4;
> exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
> exposure_max : IMX219_EXPOSURE_DEFAULT;
> @@ -817,6 +821,10 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
> struct v4l2_mbus_framefmt *format;
> struct v4l2_rect *crop;
> unsigned int bin_h, bin_v;
> + u32 prev_hts;
> +
> + format = v4l2_subdev_state_get_format(state, 0);
> + prev_hts = format->width + imx219->hblank->val;
>
> mode = v4l2_find_nearest_size(supported_modes,
> ARRAY_SIZE(supported_modes),
> @@ -824,8 +832,6 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
> fmt->format.width, fmt->format.height);
>
> imx219_update_pad_format(imx219, mode, &fmt->format, fmt->format.code);
> -
> - format = v4l2_subdev_state_get_format(state, 0);
> *format = fmt->format;
>
> /*
> @@ -861,13 +867,18 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
> 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.
> + * Retain PPL setting from previous mode so that the
> + * line time does not change on a mode change.
> + * Limits have to be recomputed as the controls define
> + * the blanking only, so PPL values need to have the
> + * mode width subtracted.
> */
> - hblank = IMX219_PPL_DEFAULT - mode->width;
> - __v4l2_ctrl_modify_range(imx219->hblank, hblank, hblank, 1,
> - hblank);
> + hblank = prev_hts - mode->width;
> + __v4l2_ctrl_modify_range(imx219->hblank,
> + IMX219_PPL_MIN - mode->width,
> + IMX219_PPL_MAX - mode->width,
> + 1, IMX219_PPL_MIN - mode->width);
> + __v4l2_ctrl_s_ctrl(imx219->hblank, hblank);

Thanks, this now looks correct to me

Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Thanks
j

> }
>
> return 0;
>
> --
> 2.47.0
>
>