git.openwrt.org Git - openwrt/staging/neocturne.git/blob

   1 From f6523a46d1ad95d1f269a691ddb7998c86b9264f Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Wed, 16 Jun 2021 17:19:17 +0100
   4 Subject: [PATCH] media: i2c: imx258: Follow normal V4L2 behaviours for
   5  clipping exposure
   6
   7 V4L2 sensor drivers are expected are expected to clip the supported
   8 exposure range based on the VBLANK configured.
   9 IMX258 wasn't doing that as register 0x350 (FRM_LENGTH_CTL)
  10 switches it to a mode where frame length tracks coarse exposure time.
  11
  12 Disable this mode and clip the range for V4L2_CID_EXPOSURE appropriately
  13 based on V4L2_CID_VBLANK.
  14
  15 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  16 ---
  17  drivers/media/i2c/imx258.c | 35 ++++++++++++++++++++++++++++-------
  18  1 file changed, 28 insertions(+), 7 deletions(-)
  19
  20 --- a/drivers/media/i2c/imx258.c
  21 +++ b/drivers/media/i2c/imx258.c
  22 @@ -32,15 +32,16 @@
  23
  24  #define IMX258_REG_VTS                 0x0340
  25
  26 -/* HBLANK control - read only */
  27 -#define IMX258_PPL_DEFAULT             5352
  28 -
  29  /* Exposure control */
  30  #define IMX258_REG_EXPOSURE            0x0202
  31 +#define IMX258_EXPOSURE_OFFSET         10
  32  #define IMX258_EXPOSURE_MIN            4
  33  #define IMX258_EXPOSURE_STEP           1
  34  #define IMX258_EXPOSURE_DEFAULT                0x640
  35 -#define IMX258_EXPOSURE_MAX            65535
  36 +#define IMX258_EXPOSURE_MAX            (IMX258_VTS_MAX - IMX258_EXPOSURE_OFFSET)
  37 +
  38 +/* HBLANK control - read only */
  39 +#define IMX258_PPL_DEFAULT             5352
  40
  41  /* Analog gain control */
  42  #define IMX258_REG_ANALOG_GAIN         0x0204
  43 @@ -377,7 +378,7 @@ static const struct imx258_reg mode_4208
  44         { 0x034D, 0x70 },
  45         { 0x034E, 0x0C },
  46         { 0x034F, 0x30 },
  47 -       { 0x0350, 0x01 },
  48 +       { 0x0350, 0x00 },
  49         { 0x0204, 0x00 },
  50         { 0x0205, 0x00 },
  51         { 0x020E, 0x01 },
  52 @@ -489,7 +490,7 @@ static const struct imx258_reg mode_2104
  53         { 0x034D, 0x38 },
  54         { 0x034E, 0x06 },
  55         { 0x034F, 0x18 },
  56 -       { 0x0350, 0x01 },
  57 +       { 0x0350, 0x00 },
  58         { 0x0204, 0x00 },
  59         { 0x0205, 0x00 },
  60         { 0x020E, 0x01 },
  61 @@ -601,7 +602,7 @@ static const struct imx258_reg mode_1048
  62         { 0x034D, 0x18 },
  63         { 0x034E, 0x03 },
  64         { 0x034F, 0x0C },
  65 -       { 0x0350, 0x01 },
  66 +       { 0x0350, 0x00 },
  67         { 0x0204, 0x00 },
  68         { 0x0205, 0x00 },
  69         { 0x020E, 0x01 },
  70 @@ -966,6 +967,19 @@ static int imx258_update_digital_gain(st
  71         return 0;
  72  }
  73
  74 +static void imx258_adjust_exposure_range(struct imx258 *imx258)
  75 +{
  76 +       int exposure_max, exposure_def;
  77 +
  78 +       /* Honour the VBLANK limits when setting exposure. */
  79 +       exposure_max = imx258->cur_mode->height + imx258->vblank->val -
  80 +                      IMX258_EXPOSURE_OFFSET;
  81 +       exposure_def = min(exposure_max, imx258->exposure->val);
  82 +       __v4l2_ctrl_modify_range(imx258->exposure, imx258->exposure->minimum,
  83 +                                exposure_max, imx258->exposure->step,
  84 +                                exposure_def);
  85 +}
  86 +
  87  static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
  88  {
  89         struct imx258 *imx258 =
  90 @@ -974,6 +988,13 @@ static int imx258_set_ctrl(struct v4l2_c
  91         int ret = 0;
  92
  93         /*
  94 +        * The VBLANK control may change the limits of usable exposure, so check
  95 +        * and adjust if necessary.
  96 +        */
  97 +       if (ctrl->id == V4L2_CID_VBLANK)
  98 +               imx258_adjust_exposure_range(imx258);
  99 +
 100 +       /*
 101          * Applying V4L2 control value only happens
 102          * when power is up for streaming
 103          */