From d66098625b057d12fcffdb07a6f2d462e0e2495d Mon Sep 17 00:00:00 2001 From: Dave Stevenson Date: Tue, 4 Jan 2022 14:46:01 +0000 Subject: [PATCH] media: i2c: ov9281: Increase diff between VTS and max exposure The driver did allow the exposure to go up to VTS - 4 lines, but this would produce a visible line on 1280x800, and a stall of the sensor at 640x480. Whilst it appears to work with a difference of 5, the datasheet states there should be at least 25 lines difference between VTS and exposure, so use that value. Signed-off-by: Dave Stevenson --- drivers/media/i2c/ov9281.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/drivers/media/i2c/ov9281.c +++ b/drivers/media/i2c/ov9281.c @@ -52,7 +52,11 @@ #define OV9281_REG_EXPOSURE 0x3500 #define OV9281_EXPOSURE_MIN 4 #define OV9281_EXPOSURE_STEP 1 -#define OV9281_VTS_MAX 0x7fff +/* + * Number of lines less than frame length (VTS) that exposure must be. + * Datasheet states 25, although empirically 5 appears to work. + */ +#define OV9281_EXPOSURE_OFFSET 25 #define OV9281_REG_GAIN_H 0x3508 #define OV9281_REG_GAIN_L 0x3509 @@ -69,6 +73,7 @@ #define OV9281_TEST_PATTERN_DISABLE 0x0 #define OV9281_REG_VTS 0x380e +#define OV9281_VTS_MAX 0x7fff /* * OV9281 native and active pixel array size. @@ -967,7 +972,7 @@ static int ov9281_set_ctrl(struct v4l2_c switch (ctrl->id) { case V4L2_CID_VBLANK: /* Update max exposure while meeting expected vblanking */ - max = ov9281->cur_mode->height + ctrl->val - 4; + max = ov9281->cur_mode->height + ctrl->val - OV9281_EXPOSURE_OFFSET; __v4l2_ctrl_modify_range(ov9281->exposure, ov9281->exposure->minimum, max, ov9281->exposure->step, @@ -1062,7 +1067,7 @@ static int ov9281_initialize_controls(st OV9281_VTS_MAX - mode->height, 1, vblank_def); - exposure_max = mode->vts_def - 4; + exposure_max = mode->vts_def - OV9281_EXPOSURE_OFFSET; ov9281->exposure = v4l2_ctrl_new_std(handler, &ov9281_ctrl_ops, V4L2_CID_EXPOSURE, OV9281_EXPOSURE_MIN, exposure_max,