From 4721f56a81e13353f6900a7346bebf330d3d560b Mon Sep 17 00:00:00 2001 From: Dave Stevenson Date: Thu, 31 Mar 2022 16:45:36 +0100 Subject: [PATCH] media: i2c: imx258: Add support for long exposure modes The sensor has a register CIT_LSHIFT which extends the exposure and frame times by the specified power of 2 for longer exposure times. Add support for this by configuring this register via V4L2_CID_VBLANK and extending the V4L2_CID_EXPOSURE range accordingly. Signed-off-by: Dave Stevenson --- drivers/media/i2c/imx258.c | 38 ++++++++++++++++++++++++++++++++------ 1 file changed, 32 insertions(+), 6 deletions(-) --- a/drivers/media/i2c/imx258.c +++ b/drivers/media/i2c/imx258.c @@ -69,6 +69,10 @@ #define IMX258_HDR_RATIO_STEP 1 #define IMX258_HDR_RATIO_DEFAULT 0x0 +/* Long exposure multiplier */ +#define IMX258_LONG_EXP_SHIFT_MAX 7 +#define IMX258_LONG_EXP_SHIFT_REG 0x3002 + /* Test Pattern Control */ #define IMX258_REG_TEST_PATTERN 0x0600 @@ -843,6 +847,8 @@ struct imx258 { struct v4l2_ctrl *exposure; struct v4l2_ctrl *hflip; struct v4l2_ctrl *vflip; + /* Current long exposure factor in use. Set through V4L2_CID_VBLANK */ + unsigned int long_exp_shift; /* Current mode */ const struct imx258_mode *cur_mode; @@ -1020,6 +1026,26 @@ static void imx258_adjust_exposure_range exposure_def); } +static int imx258_set_frame_length(struct imx258 *imx258, unsigned int val) +{ + int ret; + + imx258->long_exp_shift = 0; + + while (val > IMX258_VTS_MAX) { + imx258->long_exp_shift++; + val >>= 1; + } + + ret = imx258_write_reg(imx258, IMX258_REG_VTS, + IMX258_REG_VALUE_16BIT, val); + if (ret) + return ret; + + return imx258_write_reg(imx258, IMX258_LONG_EXP_SHIFT_REG, + IMX258_REG_VALUE_08BIT, imx258->long_exp_shift); +} + static int imx258_set_ctrl(struct v4l2_ctrl *ctrl) { struct imx258 *imx258 = @@ -1050,7 +1076,7 @@ static int imx258_set_ctrl(struct v4l2_c case V4L2_CID_EXPOSURE: ret = imx258_write_reg(imx258, IMX258_REG_EXPOSURE, IMX258_REG_VALUE_16BIT, - ctrl->val); + ctrl->val >> imx258->long_exp_shift); break; case V4L2_CID_DIGITAL_GAIN: ret = imx258_update_digital_gain(imx258, IMX258_REG_VALUE_16BIT, @@ -1078,9 +1104,8 @@ static int imx258_set_ctrl(struct v4l2_c } break; case V4L2_CID_VBLANK: - ret = imx258_write_reg(imx258, IMX258_REG_VTS, - IMX258_REG_VALUE_16BIT, - imx258->cur_mode->height + ctrl->val); + ret = imx258_set_frame_length(imx258, + imx258->cur_mode->height + ctrl->val); break; case V4L2_CID_VFLIP: case V4L2_CID_HFLIP: @@ -1218,8 +1243,9 @@ static int imx258_set_pad_format(struct imx258->cur_mode->height; __v4l2_ctrl_modify_range( imx258->vblank, vblank_min, - IMX258_VTS_MAX - imx258->cur_mode->height, 1, - vblank_def); + ((1 << IMX258_LONG_EXP_SHIFT_MAX) * IMX258_VTS_MAX) - + imx258->cur_mode->height, + 1, vblank_def); __v4l2_ctrl_s_ctrl(imx258->vblank, vblank_def); h_blank = imx258->link_freq_configs[mode->link_freq_index].pixels_per_line