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From 4721f56a81e13353f6900a7346bebf330d3d560b Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
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 <dave.stevenson@raspberrypi.com>
---
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
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