target/linux/bcm27xx/patches-5.4/950-0715-media-i2c-imx477-Add-support-for-adaptive-frame-cont.patch

   1 From 69f1022fc3c155f8cd5cf7dacaf283b1778835f3 Mon Sep 17 00:00:00 2001
   2 From: Naushir Patuck <naush@raspberrypi.com>
   3 Date: Fri, 8 May 2020 09:41:17 +0100
   4 Subject: [PATCH] media: i2c: imx477: Add support for adaptive frame
   5  control
   6
   7 Use V4L2_CID_EXPOSURE_AUTO_PRIORITY to control if the driver should
   8 automatically adjust the sensor frame length based on exposure time,
   9 allowing variable frame rates and longer exposures.
  10
  11 Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
  12 ---
  13  drivers/media/i2c/imx477.c | 113 +++++++++++++++++++++++++++++--------
  14  1 file changed, 91 insertions(+), 22 deletions(-)
  15
  16 --- a/drivers/media/i2c/imx477.c
  17 +++ b/drivers/media/i2c/imx477.c
  18 @@ -1082,6 +1082,8 @@ struct imx477 {
  19         struct v4l2_ctrl *hflip;
  20         struct v4l2_ctrl *vblank;
  21         struct v4l2_ctrl *hblank;
  22 +       /* This ctrl allows automatic variable framerate */
  23 +       struct v4l2_ctrl *exposure_auto;
  24
  25         /* Current mode */
  26         const struct imx477_mode *mode;
  27 @@ -1278,6 +1280,72 @@ static int imx477_open(struct v4l2_subde
  28         return 0;
  29  }
  30
  31 +static int imx477_set_exposure(struct imx477 *imx477, unsigned int val)
  32 +{
  33 +       int ret;
  34 +
  35 +       ret = imx477_write_reg(imx477, IMX477_REG_EXPOSURE,
  36 +                              IMX477_REG_VALUE_16BIT, val);
  37 +
  38 +       /* Setup the frame length in the case of auto framerate mode. */
  39 +       if (imx477->exposure_auto->val) {
  40 +               unsigned int frame_length, frame_length_max, frame_length_min;
  41 +
  42 +               frame_length_min = imx477->vblank->minimum +
  43 +                                  imx477->mode->height;
  44 +               frame_length_max = imx477->vblank->maximum +
  45 +                                  imx477->mode->height;
  46 +               frame_length = max(frame_length_min,
  47 +                                  val + IMX477_EXPOSURE_OFFSET);
  48 +               frame_length = min(frame_length_max, frame_length);
  49 +               ret += imx477_write_reg(imx477, IMX477_REG_FRAME_LENGTH,
  50 +                                       IMX477_REG_VALUE_16BIT, frame_length);
  51 +       }
  52 +
  53 +       return ret;
  54 +}
  55 +
  56 +static void imx477_adjust_exposure_range(struct imx477 *imx477,
  57 +                                        struct v4l2_ctrl *ctrl)
  58 +{
  59 +       int exposure_max, exposure_def;
  60 +
  61 +       if (ctrl->id == V4L2_CID_VBLANK || !ctrl->val) {
  62 +               /*
  63 +                * Either VBLANK has been changed or auto framerate
  64 +                * adjusting has been disabled. Honour the VBLANK limits
  65 +                * when setting exposure.
  66 +                */
  67 +               exposure_max = imx477->mode->height + imx477->vblank->val -
  68 +                                                     IMX477_EXPOSURE_OFFSET;
  69 +
  70 +               if (ctrl->id == V4L2_CID_EXPOSURE_AUTO_PRIORITY) {
  71 +                       /*
  72 +                        * Allow VBLANK adjustments since the driver is not
  73 +                        * handling frame length control automatically.
  74 +                        */
  75 +                       __v4l2_ctrl_grab(imx477->vblank, false);
  76 +               }
  77 +       } else {
  78 +               /*
  79 +                * Auto framerate adjusting has been enabled. VBLANK
  80 +                * ctrl has been disabled and exposure can ramp up
  81 +                * to the maximum allowable value.
  82 +                */
  83 +               exposure_max = IMX477_EXPOSURE_MAX;
  84 +               /*
  85 +                * Do not allow VBLANK adjustments if the driver is
  86 +                * handling it frame length control automatically.
  87 +                */
  88 +               __v4l2_ctrl_grab(imx477->vblank, true);
  89 +       }
  90 +
  91 +       exposure_def = min(exposure_max, imx477->exposure->val);
  92 +       __v4l2_ctrl_modify_range(imx477->exposure, imx477->exposure->minimum,
  93 +                                exposure_max, imx477->exposure->step,
  94 +                                exposure_def);
  95 +}
  96 +
  97  static int imx477_set_ctrl(struct v4l2_ctrl *ctrl)
  98  {
  99         struct imx477 *imx477 =
 100 @@ -1285,17 +1353,13 @@ static int imx477_set_ctrl(struct v4l2_c
 101         struct i2c_client *client = v4l2_get_subdevdata(&imx477->sd);
 102         int ret = 0;
 103
 104 -       if (ctrl->id == V4L2_CID_VBLANK) {
 105 -               int exposure_max, exposure_def;
 106 -
 107 -               /* Update max exposure while meeting expected vblanking */
 108 -               exposure_max = imx477->mode->height + ctrl->val -
 109 -                                                       IMX477_EXPOSURE_OFFSET;
 110 -               exposure_def = min(exposure_max, imx477->exposure->val);
 111 -               __v4l2_ctrl_modify_range(imx477->exposure,
 112 -                                        imx477->exposure->minimum,
 113 -                                        exposure_max, imx477->exposure->step,
 114 -                                        exposure_def);
 115 +       if (ctrl->id == V4L2_CID_VBLANK ||
 116 +           ctrl->id == V4L2_CID_EXPOSURE_AUTO_PRIORITY) {
 117 +               /*
 118 +                * These controls may change the limits of usable exposure,
 119 +                * so check and adjust if necessary.
 120 +                */
 121 +               imx477_adjust_exposure_range(imx477, ctrl);
 122         }
 123
 124         /*
 125 @@ -1311,8 +1375,14 @@ static int imx477_set_ctrl(struct v4l2_c
 126                                        IMX477_REG_VALUE_16BIT, ctrl->val);
 127                 break;
 128         case V4L2_CID_EXPOSURE:
 129 -               ret = imx477_write_reg(imx477, IMX477_REG_EXPOSURE,
 130 -                                      IMX477_REG_VALUE_16BIT, ctrl->val);
 131 +               ret = imx477_set_exposure(imx477, ctrl->val);
 132 +               break;
 133 +       case V4L2_CID_EXPOSURE_AUTO_PRIORITY:
 134 +               /*
 135 +                * imx477_set_exposure() will recalculate the frame length
 136 +                * to adjust the framerate to match the exposure.
 137 +                */
 138 +               ret = imx477_set_exposure(imx477, imx477->exposure->val);
 139                 break;
 140         case V4L2_CID_DIGITAL_GAIN:
 141                 ret = imx477_write_reg(imx477, IMX477_REG_DIGITAL_GAIN,
 142 @@ -1510,9 +1580,8 @@ unsigned int imx477_get_frame_length(con
 143
 144  static void imx477_set_framing_limits(struct imx477 *imx477)
 145  {
 146 +       unsigned int frm_length_min, frm_length_default, hblank;
 147         const struct imx477_mode *mode = imx477->mode;
 148 -       unsigned int frm_length_min, frm_length_default;
 149 -       unsigned int exposure_max, exposure_def, hblank;
 150
 151         frm_length_min = imx477_get_frame_length(mode, &mode->timeperframe_min);
 152         frm_length_default =
 153 @@ -1522,15 +1591,10 @@ static void imx477_set_framing_limits(st
 154         __v4l2_ctrl_modify_range(imx477->vblank, frm_length_min - mode->height,
 155                                  IMX477_FRAME_LENGTH_MAX - mode->height,
 156                                  1, frm_length_default - mode->height);
 157 +
 158 +       /* Setting this will adjust the exposure limits as well. */
 159         __v4l2_ctrl_s_ctrl(imx477->vblank, frm_length_default - mode->height);
 160
 161 -       /* Update max exposure while meeting expected vblanking */
 162 -       exposure_max = IMX477_FRAME_LENGTH_MAX - IMX477_EXPOSURE_OFFSET;
 163 -       exposure_def = frm_length_default - mode->height -
 164 -                                           IMX477_EXPOSURE_OFFSET;
 165 -       __v4l2_ctrl_modify_range(imx477->exposure, imx477->exposure->minimum,
 166 -                                exposure_max, imx477->exposure->step,
 167 -                                exposure_def);
 168         /*
 169          * Currently PPL is fixed to the mode specified value, so hblank
 170          * depends on mode->width only, and is not changeable in any
 171 @@ -1939,6 +2003,11 @@ static int imx477_init_controls(struct i
 172                           IMX477_DGTL_GAIN_MIN, IMX477_DGTL_GAIN_MAX,
 173                           IMX477_DGTL_GAIN_STEP, IMX477_DGTL_GAIN_DEFAULT);
 174
 175 +       imx477->exposure_auto =
 176 +                       v4l2_ctrl_new_std(ctrl_hdlr, &imx477_ctrl_ops,
 177 +                                         V4L2_CID_EXPOSURE_AUTO_PRIORITY,
 178 +                                         0, 1, 1, 0);
 179 +
 180         imx477->hflip = v4l2_ctrl_new_std(ctrl_hdlr, &imx477_ctrl_ops,
 181                                           V4L2_CID_HFLIP, 0, 1, 1, 0);
 182         if (imx477->hflip)