Hi Jai
On Mon, 30 Dec 2024 at 06:12, Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx> wrote:
>
> From: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
>
> The HBLANK control was read-only, and always configured such that the
> sensor line length 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 line length setting when changing modes rather than resetting it
> to a default.
>
> Signed-off-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> Reviewed-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
> Signed-off-by: Jai Luthra <jai.luthra@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/i2c/imx219.c | 49 +++++++++++++++++++++++++++-------------------
> 1 file changed, 29 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index 8565b1b030be2ee24bcc37415e99ee4ef83cc683..9682a74feb3b7b74cd2ca54779323396c77cd5a5 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -73,11 +73,10 @@
> #define IMX219_REG_FRM_LENGTH CCI_REG16(0x0160)
> #define IMX219_FLL_MAX 0xffff
> #define IMX219_VBLANK_MIN 32
> +#define IMX219_REG_LINE_LENGTH CCI_REG16(0x0162)
The datasheet calls the register LINE_LENGTH_A as it has an A and B
back of settings for quick switching between the two. Whilst we don't
use the quick mode switching, IMHO using the correct name is sensible.
Same is true for 0x0160 being FRM_LENGTH_A, not just FRM_LENGTH
(should be part of 2/5 if adopted).
> +#define IMX219_LLP_MIN 0x0d78
> +#define IMX219_LLP_MAX 0x7ff0
>
> -/* HBLANK control - read only */
> -#define IMX219_PPL_DEFAULT 3448
> -
> -#define IMX219_REG_LINE_LENGTH_A CCI_REG16(0x0162)
> #define IMX219_REG_X_ADD_STA_A CCI_REG16(0x0164)
> #define IMX219_REG_X_ADD_END_A CCI_REG16(0x0166)
> #define IMX219_REG_Y_ADD_STA_A CCI_REG16(0x0168)
> @@ -191,7 +190,7 @@ static const struct cci_reg_sequence imx219_common_regs[] = {
> { CCI_REG8(0x479b), 0x0e },
>
> /* Frame Bank Register Group "A" */
> - { IMX219_REG_LINE_LENGTH_A, 3448 },
> + { IMX219_REG_LINE_LENGTH, IMX219_LLP_MIN },
LINE_LENGTH is also set from imx219_set_ctrl for V4L2_CID_HBLANK, so
this line is redundant and should be removed.
(I'm aware that I missed removing it in the downstream version of this
patch - it's only your rename that highlighted it).
Otherwise this looks good to me.
Dave
> { IMX219_REG_X_ODD_INC_A, 1 },
> { IMX219_REG_Y_ODD_INC_A, 1 },
>
> @@ -420,6 +419,10 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
> cci_write(imx219->regmap, IMX219_REG_FRM_LENGTH,
> format->height + ctrl->val, &ret);
> break;
> + case V4L2_CID_HBLANK:
> + cci_write(imx219->regmap, IMX219_REG_LINE_LENGTH,
> + format->width + ctrl->val, &ret);
> + break;
> case V4L2_CID_TEST_PATTERN_RED:
> cci_write(imx219->regmap, IMX219_REG_TESTP_RED,
> ctrl->val, &ret);
> @@ -465,7 +468,7 @@ static int imx219_init_controls(struct imx219 *imx219)
> const struct imx219_mode *mode = &supported_modes[0];
> struct v4l2_ctrl_handler *ctrl_hdlr;
> struct v4l2_fwnode_device_properties props;
> - int exposure_max, exposure_def, hblank;
> + int exposure_max, exposure_def;
> int i, ret;
>
> ctrl_hdlr = &imx219->ctrl_handler;
> @@ -489,17 +492,16 @@ static int imx219_init_controls(struct imx219 *imx219)
> if (imx219->link_freq)
> imx219->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
>
> - /* Initial vblank/hblank/exposure parameters based on current mode */
> + /* Initial blanking and exposure. Limits are updated during set_fmt */
> imx219->vblank = v4l2_ctrl_new_std(ctrl_hdlr, &imx219_ctrl_ops,
> V4L2_CID_VBLANK, IMX219_VBLANK_MIN,
> IMX219_FLL_MAX - mode->height, 1,
> mode->fll_def - mode->height);
> - hblank = IMX219_PPL_DEFAULT - 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;
> + V4L2_CID_HBLANK,
> + IMX219_LLP_MIN - mode->width,
> + IMX219_LLP_MAX - mode->width, 1,
> + IMX219_LLP_MIN - mode->width);
> exposure_max = mode->fll_def - 4;
> exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
> exposure_max : IMX219_EXPOSURE_DEFAULT;
> @@ -815,6 +817,10 @@ 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_line_len;
> +
> + format = v4l2_subdev_state_get_format(state, 0);
> + prev_line_len = format->width + imx219->hblank->val;
>
> mode = v4l2_find_nearest_size(supported_modes,
> ARRAY_SIZE(supported_modes),
> @@ -822,8 +828,6 @@ 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;
>
> /*
> @@ -859,13 +863,18 @@ 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_line_len - mode->width;
> + __v4l2_ctrl_modify_range(imx219->hblank,
> + IMX219_LLP_MIN - mode->width,
> + IMX219_LLP_MAX - mode->width, 1,
> + IMX219_LLP_MIN - mode->width);
> + __v4l2_ctrl_s_ctrl(imx219->hblank, hblank);
> }
>
> return 0;
>
> --
> 2.47.1
>
