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media: i2c: imx477: Add support for adaptive frame control

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Use V4L2_CID_EXPOSURE_AUTO_PRIORITY to control if the driver should
automatically adjust the sensor frame length based on exposure time,
allowing variable frame rates and longer exposures.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
This commit is contained in:
Naushir Patuck
2020-05-08 09:41:17 +01:00
committed by popcornmix
parent 694fcbddfd
commit ac7303bccd
1 changed files with 91 additions and 22 deletions
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113
drivers/media/i2c/imx477.c
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@@ -1082,6 +1082,8 @@ struct imx477 {
struct v4l2_ctrl *hflip;
struct v4l2_ctrl *vblank;
struct v4l2_ctrl *hblank;
/* This ctrl allows automatic variable framerate */
struct v4l2_ctrl *exposure_auto;
/* Current mode */
const struct imx477_mode *mode;
@@ -1278,6 +1280,72 @@ static int imx477_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
return 0;
}
static int imx477_set_exposure(struct imx477 *imx477, unsigned int val)
{
int ret;
ret = imx477_write_reg(imx477, IMX477_REG_EXPOSURE,
IMX477_REG_VALUE_16BIT, val);
/* Setup the frame length in the case of auto framerate mode. */
if (imx477->exposure_auto->val) {
unsigned int frame_length, frame_length_max, frame_length_min;
frame_length_min = imx477->vblank->minimum +
imx477->mode->height;
frame_length_max = imx477->vblank->maximum +
imx477->mode->height;
frame_length = max(frame_length_min,
val + IMX477_EXPOSURE_OFFSET);
frame_length = min(frame_length_max, frame_length);
ret += imx477_write_reg(imx477, IMX477_REG_FRAME_LENGTH,
IMX477_REG_VALUE_16BIT, frame_length);
}
return ret;
}
static void imx477_adjust_exposure_range(struct imx477 *imx477,
struct v4l2_ctrl *ctrl)
{
int exposure_max, exposure_def;
if (ctrl->id == V4L2_CID_VBLANK || !ctrl->val) {
/*
* Either VBLANK has been changed or auto framerate
* adjusting has been disabled. Honour the VBLANK limits
* when setting exposure.
*/
exposure_max = imx477->mode->height + imx477->vblank->val -
IMX477_EXPOSURE_OFFSET;
if (ctrl->id == V4L2_CID_EXPOSURE_AUTO_PRIORITY) {
/*
* Allow VBLANK adjustments since the driver is not
* handling frame length control automatically.
*/
__v4l2_ctrl_grab(imx477->vblank, false);
}
} else {
/*
* Auto framerate adjusting has been enabled. VBLANK
* ctrl has been disabled and exposure can ramp up
* to the maximum allowable value.
*/
exposure_max = IMX477_EXPOSURE_MAX;
/*
* Do not allow VBLANK adjustments if the driver is
* handling it frame length control automatically.
*/
__v4l2_ctrl_grab(imx477->vblank, true);
}
exposure_def = min(exposure_max, imx477->exposure->val);
__v4l2_ctrl_modify_range(imx477->exposure, imx477->exposure->minimum,
exposure_max, imx477->exposure->step,
exposure_def);
}
static int imx477_set_ctrl(struct v4l2_ctrl *ctrl)
{
struct imx477 *imx477 =
@@ -1285,17 +1353,13 @@ static int imx477_set_ctrl(struct v4l2_ctrl *ctrl)
struct i2c_client *client = v4l2_get_subdevdata(&imx477->sd);
int ret = 0;
if (ctrl->id == V4L2_CID_VBLANK) {
int exposure_max, exposure_def;
/* Update max exposure while meeting expected vblanking */
exposure_max = imx477->mode->height + ctrl->val -
IMX477_EXPOSURE_OFFSET;
exposure_def = min(exposure_max, imx477->exposure->val);
__v4l2_ctrl_modify_range(imx477->exposure,
imx477->exposure->minimum,
exposure_max, imx477->exposure->step,
exposure_def);
if (ctrl->id == V4L2_CID_VBLANK ||
ctrl->id == V4L2_CID_EXPOSURE_AUTO_PRIORITY) {
/*
* These controls may change the limits of usable exposure,
* so check and adjust if necessary.
*/
imx477_adjust_exposure_range(imx477, ctrl);
}
/*
@@ -1311,8 +1375,14 @@ static int imx477_set_ctrl(struct v4l2_ctrl *ctrl)
IMX477_REG_VALUE_16BIT, ctrl->val);
break;
case V4L2_CID_EXPOSURE:
ret = imx477_write_reg(imx477, IMX477_REG_EXPOSURE,
IMX477_REG_VALUE_16BIT, ctrl->val);
ret = imx477_set_exposure(imx477, ctrl->val);
break;
case V4L2_CID_EXPOSURE_AUTO_PRIORITY:
/*
* imx477_set_exposure() will recalculate the frame length
* to adjust the framerate to match the exposure.
*/
ret = imx477_set_exposure(imx477, imx477->exposure->val);
break;
case V4L2_CID_DIGITAL_GAIN:
ret = imx477_write_reg(imx477, IMX477_REG_DIGITAL_GAIN,
@@ -1510,9 +1580,8 @@ unsigned int imx477_get_frame_length(const struct imx477_mode *mode,
static void imx477_set_framing_limits(struct imx477 *imx477)
{
unsigned int frm_length_min, frm_length_default, hblank;
const struct imx477_mode *mode = imx477->mode;
unsigned int frm_length_min, frm_length_default;
unsigned int exposure_max, exposure_def, hblank;
frm_length_min = imx477_get_frame_length(mode, &mode->timeperframe_min);
frm_length_default =
@@ -1522,15 +1591,10 @@ static void imx477_set_framing_limits(struct imx477 *imx477)
__v4l2_ctrl_modify_range(imx477->vblank, frm_length_min - mode->height,
IMX477_FRAME_LENGTH_MAX - mode->height,
1, frm_length_default - mode->height);
/* Setting this will adjust the exposure limits as well. */
__v4l2_ctrl_s_ctrl(imx477->vblank, frm_length_default - mode->height);
/* Update max exposure while meeting expected vblanking */
exposure_max = IMX477_FRAME_LENGTH_MAX - IMX477_EXPOSURE_OFFSET;
exposure_def = frm_length_default - mode->height -
IMX477_EXPOSURE_OFFSET;
__v4l2_ctrl_modify_range(imx477->exposure, imx477->exposure->minimum,
exposure_max, imx477->exposure->step,
exposure_def);
/*
* Currently PPL is fixed to the mode specified value, so hblank
* depends on mode->width only, and is not changeable in any
@@ -1939,6 +2003,11 @@ static int imx477_init_controls(struct imx477 *imx477)
IMX477_DGTL_GAIN_MIN, IMX477_DGTL_GAIN_MAX,
IMX477_DGTL_GAIN_STEP, IMX477_DGTL_GAIN_DEFAULT);
imx477->exposure_auto =
v4l2_ctrl_new_std(ctrl_hdlr, &imx477_ctrl_ops,
V4L2_CID_EXPOSURE_AUTO_PRIORITY,
0, 1, 1, 0);
imx477->hflip = v4l2_ctrl_new_std(ctrl_hdlr, &imx477_ctrl_ops,
V4L2_CID_HFLIP, 0, 1, 1, 0);
if (imx477->hflip)