[PATCH] media: imx208: support adjust range of exposure per VBLANK control

[PATCH] media: imx208: support adjust range of exposure per VBLANK control

[Bingbu Cao]

From: Qingwu Zhang <qingwu.zhang@intel.com>

Current the max value of imx208 exposure time was hardcoded to 15ms,
it will cause the sensor can not support longer exposure time such as
30ms and 66ms, this patch add support of setting the VBLANK control to
increase the exposure range to meet expected longer exposure.

Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Qingwu Zhang <qingwu.zhang@intel.com>
---
 drivers/media/i2c/imx208.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/media/i2c/imx208.c b/drivers/media/i2c/imx208.c
index 6f3d9c1b5879..83d581967c6d 100644
--- a/drivers/media/i2c/imx208.c
+++ b/drivers/media/i2c/imx208.c
@@ -277,6 +277,7 @@ struct imx208 {
 	struct v4l2_ctrl *pixel_rate;
 	struct v4l2_ctrl *vblank;
 	struct v4l2_ctrl *hblank;
+	struct v4l2_ctrl *exposure;
 	struct v4l2_ctrl *vflip;
 	struct v4l2_ctrl *hflip;
 
@@ -432,8 +433,17 @@ static int imx208_set_ctrl(struct v4l2_ctrl *ctrl)
 	struct imx208 *imx208 =
 		container_of(ctrl->handler, struct imx208, ctrl_handler);
 	struct i2c_client *client = v4l2_get_subdevdata(&imx208->sd);
+	s64 max;
 	int ret;
 
+	if (ctrl->id == V4L2_CID_VBLANK) {
+		/* Update max exposure while meeting expected vblanking */
+		max = imx208->cur_mode->height + ctrl->val - 8;
+		__v4l2_ctrl_modify_range(imx208->exposure,
+					 imx208->exposure->minimum,
+					 max, imx208->exposure->step, max);
+	}
+
 	/*
 	 * Applying V4L2 control value only happens
 	 * when power is up for streaming
@@ -914,9 +924,11 @@ static int imx208_init_controls(struct imx208 *imx208)
 		imx208->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
 
 	exposure_max = imx208->cur_mode->vts_def - 8;
-	v4l2_ctrl_new_std(ctrl_hdlr, &imx208_ctrl_ops, V4L2_CID_EXPOSURE,
-			  IMX208_EXPOSURE_MIN, exposure_max,
-			  IMX208_EXPOSURE_STEP, IMX208_EXPOSURE_DEFAULT);
+	imx208->exposure = v4l2_ctrl_new_std(ctrl_hdlr, &imx208_ctrl_ops,
+					     V4L2_CID_EXPOSURE,
+					     IMX208_EXPOSURE_MIN, exposure_max,
+					     IMX208_EXPOSURE_STEP,
+					     IMX208_EXPOSURE_DEFAULT);
 
 	imx208->hflip = v4l2_ctrl_new_std(ctrl_hdlr, &imx208_ctrl_ops,
 					  V4L2_CID_HFLIP, 0, 1, 1, 0);
-- 
2.7.4