[PATCH v1 2/2] media: i2c: imx219: Replace exposure magic value with named constant

From: Tarang Raval

Date: Fri Oct 31 2025 - 07:49:06 EST


Introduce IMX219_EXPOSURE_OFFSET (4) and use it instead of the literal
'4' when computing the maximum coarse exposure. The IMX219 datasheet
specifies the maximum storage time as frame_length_lines - 4.
(Ref: Datasheet section 5-7-1)

Also fix one indentation issue for consistency.

Signed-off-by: Tarang Raval <tarang.raval@xxxxxxxxxxxxxxxxx>
---
drivers/media/i2c/imx219.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
index 40693635c0c3..e87d5a18fe87 100644
--- a/drivers/media/i2c/imx219.c
+++ b/drivers/media/i2c/imx219.c
@@ -68,6 +68,7 @@
#define IMX219_EXPOSURE_STEP 1
#define IMX219_EXPOSURE_DEFAULT 0x640
#define IMX219_EXPOSURE_MAX 65535
+#define IMX219_EXPOSURE_OFFSET 4

/* V_TIMING internal */
#define IMX219_REG_FRM_LENGTH_A CCI_REG16(0x0160)
@@ -450,9 +451,9 @@ static int imx219_set_ctrl(struct v4l2_ctrl *ctrl)
int exposure_max, exposure_def;

/* Update max exposure while meeting expected vblanking */
- exposure_max = format->height + ctrl->val - 4;
+ exposure_max = format->height + ctrl->val - IMX219_EXPOSURE_OFFSET;
exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
- exposure_max : IMX219_EXPOSURE_DEFAULT;
+ exposure_max : IMX219_EXPOSURE_DEFAULT;
ret = __v4l2_ctrl_modify_range(imx219->exposure,
imx219->exposure->minimum,
exposure_max,
@@ -579,9 +580,9 @@ static int imx219_init_controls(struct imx219 *imx219)
IMX219_LLP_MIN - mode->width,
IMX219_LLP_MAX - mode->width, 1,
IMX219_LLP_MIN - mode->width);
- exposure_max = mode->fll_def - 4;
+ exposure_max = mode->fll_def - IMX219_EXPOSURE_OFFSET;
exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
- exposure_max : IMX219_EXPOSURE_DEFAULT;
+ exposure_max : IMX219_EXPOSURE_DEFAULT;
imx219->exposure = v4l2_ctrl_new_std(ctrl_hdlr, &imx219_ctrl_ops,
V4L2_CID_EXPOSURE,
IMX219_EXPOSURE_MIN, exposure_max,
@@ -900,9 +901,9 @@ static int imx219_set_pad_format(struct v4l2_subdev *sd,
return ret;

/* Update max exposure while meeting expected vblanking */
- exposure_max = mode->fll_def - 4;
+ exposure_max = mode->fll_def - IMX219_EXPOSURE_OFFSET;
exposure_def = (exposure_max < IMX219_EXPOSURE_DEFAULT) ?
- exposure_max : IMX219_EXPOSURE_DEFAULT;
+ exposure_max : IMX219_EXPOSURE_DEFAULT;
ret = __v4l2_ctrl_modify_range(imx219->exposure,
imx219->exposure->minimum,
exposure_max,
--
2.34.1