From 69f1022fc3c155f8cd5cf7dacaf283b1778835f3 Mon Sep 17 00:00:00 2001 From: Naushir Patuck Date: Fri, 8 May 2020 09:41:17 +0100 Subject: [PATCH] media: i2c: imx477: Add support for adaptive frame control 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 --- drivers/media/i2c/imx477.c | 113 +++++++++++++++++++++++++++++-------- 1 file changed, 91 insertions(+), 22 deletions(-) --- a/drivers/media/i2c/imx477.c +++ b/drivers/media/i2c/imx477.c @@ -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_subde 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_c 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_c 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(con 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(st __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 i 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)