Re: [PATCH v3 07/12] media: i2c: imx214: Add vblank and hblank controls

From: André Apitzsch
Date: Sun Dec 08 2024 - 16:35:41 EST


Hi Ricardo,

Am Sonntag, dem 08.12.2024 um 21:59 +0100 schrieb Ricardo Ribalda
Delgado:
> In general it looks good to me (besides the comments, ignore the nits
> if you want to).
>
> I'd recommend that you test with lockdep to make sure that we are not
> missing anything, and I'd like to hear back from Sakari regarding the
> get_locked_active
>
> Thanks!
>
> On Sat, Dec 7, 2024 at 9:48 PM André Apitzsch via B4 Relay
> <devnull+git.apitzsch.eu@xxxxxxxxxx> wrote:
> >
> > From: André Apitzsch <git@xxxxxxxxxxx>
> >
> > Add vblank control to allow changing the framerate /
> > higher exposure values.
> >
> > The vblank and hblank controls are needed for libcamera support.
> >
> > While at it, fix the minimal exposure time according to the
> > datasheet.
> >
> > Signed-off-by: André Apitzsch <git@xxxxxxxxxxx>
> > ---
> >  drivers/media/i2c/imx214.c | 106
> > ++++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 94 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/media/i2c/imx214.c
> > b/drivers/media/i2c/imx214.c
> > index
> > f1c72db0775eaf4810f762e8798d301c5ad9923c..a7f49dbafe0f54af3c02f5534
> > 460fdee88a22fe2 100644
> > --- a/drivers/media/i2c/imx214.c
> > +++ b/drivers/media/i2c/imx214.c
> > @@ -34,11 +34,17 @@
> >
> >  /* V-TIMING internal */
> >  #define IMX214_REG_FRM_LENGTH_LINES    CCI_REG16(0x0340)
> > +#define IMX214_VTS_MAX                 0xffff
> > +
> > +#define IMX214_VBLANK_MIN              890
> > +
> > +/* HBLANK control - read only */
> > +#define IMX214_PPL_DEFAULT             5008
> >
> >  /* Exposure control */
> >  #define IMX214_REG_EXPOSURE            CCI_REG16(0x0202)
> > -#define IMX214_EXPOSURE_MIN            0
> > -#define IMX214_EXPOSURE_MAX            3184
> > +#define IMX214_EXPOSURE_OFFSET         10
> > +#define IMX214_EXPOSURE_MIN            1
> >  #define IMX214_EXPOSURE_STEP           1
> >  #define IMX214_EXPOSURE_DEFAULT                3184
> >  #define IMX214_REG_EXPOSURE_RATIO      CCI_REG8(0x0222)
> > @@ -187,6 +193,8 @@ struct imx214 {
> >         struct v4l2_ctrl_handler ctrls;
> >         struct v4l2_ctrl *pixel_rate;
> >         struct v4l2_ctrl *link_freq;
> > +       struct v4l2_ctrl *vblank;
> > +       struct v4l2_ctrl *hblank;
> >         struct v4l2_ctrl *exposure;
> >         struct v4l2_ctrl *unit_size;
> >
> > @@ -202,8 +210,6 @@ static const struct cci_reg_sequence
> > mode_4096x2304[] = {
> >         { IMX214_REG_HDR_MODE, IMX214_HDR_MODE_OFF },
> >         { IMX214_REG_HDR_RES_REDUCTION, IMX214_HDR_RES_REDU_THROUGH
> > },
> >         { IMX214_REG_EXPOSURE_RATIO, 1 },
> > -       { IMX214_REG_FRM_LENGTH_LINES, 3194 },
> > -       { IMX214_REG_LINE_LENGTH_PCK, 5008 },
> >         { IMX214_REG_X_ADD_STA, 56 },
> >         { IMX214_REG_Y_ADD_STA, 408 },
> >         { IMX214_REG_X_ADD_END, 4151 },
> > @@ -274,8 +280,6 @@ static const struct cci_reg_sequence
> > mode_1920x1080[] = {
> >         { IMX214_REG_HDR_MODE, IMX214_HDR_MODE_OFF },
> >         { IMX214_REG_HDR_RES_REDUCTION, IMX214_HDR_RES_REDU_THROUGH
> > },
> >         { IMX214_REG_EXPOSURE_RATIO, 1 },
> > -       { IMX214_REG_FRM_LENGTH_LINES, 3194 },
> > -       { IMX214_REG_LINE_LENGTH_PCK, 5008 },
> >         { IMX214_REG_X_ADD_STA, 1144 },
> >         { IMX214_REG_Y_ADD_STA, 1020 },
> >         { IMX214_REG_X_ADD_END, 3063 },
> > @@ -359,6 +363,7 @@ static const struct cci_reg_sequence
> > mode_table_common[] = {
> >         { IMX214_REG_ORIENTATION, 0 },
> >         { IMX214_REG_MASK_CORR_FRAMES, IMX214_CORR_FRAMES_MASK },
> >         { IMX214_REG_FAST_STANDBY_CTRL, 1 },
> > +       { IMX214_REG_LINE_LENGTH_PCK, IMX214_PPL_DEFAULT },
> >         { CCI_REG8(0x4550), 0x02 },
> >         { CCI_REG8(0x4601), 0x00 },
> >         { CCI_REG8(0x4642), 0x05 },
> > @@ -462,18 +467,24 @@ static const struct cci_reg_sequence
> > mode_table_common[] = {
> >  static const struct imx214_mode {
> >         u32 width;
> >         u32 height;
> > +
> > +       /* V-timing */
> > +       unsigned int vts_def;
> > +
> >         unsigned int num_of_regs;
> >         const struct cci_reg_sequence *reg_table;
> >  } imx214_modes[] = {
> >         {
> >                 .width = 4096,
> >                 .height = 2304,
> > +               .vts_def = 3194,
> >                 .num_of_regs = ARRAY_SIZE(mode_4096x2304),
> >                 .reg_table = mode_4096x2304,
> >         },
> >         {
> >                 .width = 1920,
> >                 .height = 1080,
> > +               .vts_def = 3194,
> >                 .num_of_regs = ARRAY_SIZE(mode_1920x1080),
> >                 .reg_table = mode_1920x1080,
> >         },
> > @@ -626,9 +637,36 @@ static int imx214_set_format(struct
> > v4l2_subdev *sd,
> >         __crop->width = mode->width;
> >         __crop->height = mode->height;
> >
> > -       if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE)
> > +       if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> > +               int exposure_max;
> > +               int exposure_def;
> > +               int hblank;
> > +
> >                 imx214->cur_mode = mode;
> >
> > +               /* Update FPS limits */
> nit: Update blank limits
> > +               __v4l2_ctrl_modify_range(imx214->vblank,
> > IMX214_VBLANK_MIN,
> > +                                        IMX214_VTS_MAX - mode-
> > >height, 2,
> > +                                        mode->vts_def - mode-
> > >height);
>
> Is the handler->lock held when we call this function? Can you try
> running the code with lockdep?
> > +
> > +               /* Update max exposure while meeting expected
> > vblanking */
> > +               exposure_max = mode->vts_def -
> > IMX214_EXPOSURE_OFFSET;
> > +               exposure_def = min(exposure_max,
> > IMX214_EXPOSURE_DEFAULT);
> > +               __v4l2_ctrl_modify_range(imx214->exposure,
> > +                                        imx214->exposure->minimum,
> > +                                        exposure_max, imx214-
> > >exposure->step,
> > +                                        exposure_def);
> > +
> > +               /*
> > +                * Currently PPL is fixed to IMX214_PPL_DEFAULT, so
> > hblank
> > +                * depends on mode->width only, and is not
> > changeable in any
> > +                * way other than changing the mode.
> > +                */
> > +               hblank = IMX214_PPL_DEFAULT - mode->width;
> > +               __v4l2_ctrl_modify_range(imx214->hblank, hblank,
> > hblank, 1,
> > +                                        hblank);
> > +       }
> > +
> >         return 0;
> >  }
> >
> > @@ -678,8 +716,25 @@ static int imx214_set_ctrl(struct v4l2_ctrl
> > *ctrl)
> >  {
> >         struct imx214 *imx214 = container_of(ctrl->handler,
> >                                              struct imx214, ctrls);
> > +       const struct v4l2_mbus_framefmt *format;
> > +       struct v4l2_subdev_state *state;
> >         int ret;
> >
> > +       if (ctrl->id == V4L2_CID_VBLANK) {
> > +               int exposure_max, exposure_def;
> > +
> > +               state =
> > v4l2_subdev_get_locked_active_state(&imx214->sd);
>
> Sakari, I see that other drivers assume that the active is locked in
> set_ctrl. Is this correct?
>
> > +               format = v4l2_subdev_state_get_format(state, 0);

(*) The format is read here.

> > +
> > +               /* Update max exposure while meeting expected
> > vblanking */
> > +               exposure_max = format->height + ctrl->val -
> > IMX214_EXPOSURE_OFFSET;
> > +               exposure_def = min(exposure_max,
> > IMX214_EXPOSURE_DEFAULT);
> > +               __v4l2_ctrl_modify_range(imx214->exposure,
> > +                                        imx214->exposure->minimum,
> > +                                        exposure_max, imx214-
> > >exposure->step,
> > +                                        exposure_def);
> > +       }
> > +
> >         /*
> >          * Applying V4L2 control value only happens
> >          * when power is up for streaming
> > @@ -691,7 +746,10 @@ static int imx214_set_ctrl(struct v4l2_ctrl
> > *ctrl)
> >         case V4L2_CID_EXPOSURE:
> >                 cci_write(imx214->regmap, IMX214_REG_EXPOSURE,
> > ctrl->val, &ret);
> >                 break;
> > -
> > +       case V4L2_CID_VBLANK:
>  No need to read the format here?
>                       format = v4l2_subdev_state_get_format(state,
> 0);

The format is read above (*), so no need to do it here. Note, in both
locations we have ctrl->id == V4L2_CID_VBLANK.

> > +               cci_write(imx214->regmap,
> > IMX214_REG_FRM_LENGTH_LINES,
> > +                         format->height + ctrl->val, &ret);
> > +               break;
> >         default:
> >                 ret = -EINVAL;
> >         }
> > @@ -714,8 +772,11 @@ static int imx214_ctrls_init(struct imx214
> > *imx214)
> >                 .width = 1120,
> >                 .height = 1120,
> >         };
> > +       const struct imx214_mode *mode = &imx214_modes[0];
> >         struct v4l2_fwnode_device_properties props;
> >         struct v4l2_ctrl_handler *ctrl_hdlr;
> > +       int exposure_max, exposure_def;
> > +       int hblank;
> >         int ret;
> >
> >         ret = v4l2_fwnode_device_parse(imx214->dev, &props);
> > @@ -723,7 +784,7 @@ static int imx214_ctrls_init(struct imx214
> > *imx214)
> >                 return ret;
> >
> >         ctrl_hdlr = &imx214->ctrls;
> > -       ret = v4l2_ctrl_handler_init(&imx214->ctrls, 6);
> > +       ret = v4l2_ctrl_handler_init(&imx214->ctrls, 8);
> >         if (ret)
> >                 return ret;
> >
> > @@ -749,12 +810,27 @@ static int imx214_ctrls_init(struct imx214
> > *imx214)
> >          *
> >          * Yours sincerely, Ricardo.
> >          */
> > +
> > +       /* Initial vblank/hblank/exposure parameters based on
> > current mode */
> > +       imx214->vblank = v4l2_ctrl_new_std(ctrl_hdlr,
> > &imx214_ctrl_ops,
> > +                                          V4L2_CID_VBLANK,
> > IMX214_VBLANK_MIN,
> > +                                          IMX214_VTS_MAX - mode-
> > >height, 2,
> > +                                          mode->vts_def - mode-
> > >height);
> > +
> > +       hblank = IMX214_PPL_DEFAULT - mode->width;
> > +       imx214->hblank = v4l2_ctrl_new_std(ctrl_hdlr,
> > &imx214_ctrl_ops,
> > +                                          V4L2_CID_HBLANK, hblank,
> > hblank,
> > +                                          1, hblank);
> > +       if (imx214->hblank)
> > +               imx214->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> > +
> > +       exposure_max = mode->vts_def - IMX214_EXPOSURE_OFFSET;
> > +       exposure_def = min(exposure_max, IMX214_EXPOSURE_DEFAULT);
> >         imx214->exposure = v4l2_ctrl_new_std(ctrl_hdlr,
> > &imx214_ctrl_ops,
> >                                              V4L2_CID_EXPOSURE,
> > -                                            IMX214_EXPOSURE_MIN,
> > -                                            IMX214_EXPOSURE_MAX,
> > +                                            IMX214_EXPOSURE_MIN,
> > exposure_max,
> nit: I think it looks nicer with exposure_max in the next line, but
> ignore if you prefer this way :)
> >                                              IMX214_EXPOSURE_STEP,
> > -                                           
> > IMX214_EXPOSURE_DEFAULT);
> > +                                            exposure_def);
> >
> >         imx214->unit_size = v4l2_ctrl_new_std_compound(ctrl_hdlr,
> >                                 NULL,
> > @@ -876,6 +952,12 @@ static int imx214_get_frame_interval(struct
> > v4l2_subdev *subdev,
> >         return 0;
> >  }
> >
> > +/*
> > + * Raw sensors should be using the VBLANK and HBLANK controls to
> > determine
> > + * the frame rate. However this driver was initially added using
> > the
> > + * [S|G|ENUM]_FRAME_INTERVAL ioctls with a fixed rate of 30fps.
> > + * Retain the frame_interval ops for backwards compatibility, but
> > they do nothing.
> > + */
>
> Now that these controls are useless... maybe we can do a
> dev_warn_once
> when the user calls it to leave some output in dmesg?

Sure. We the following be a proper warning?

"Use the VBLANK and HBLANK controls to determine the frame rate\n"

> >  static int imx214_enum_frame_interval(struct v4l2_subdev *subdev,
> >                                 struct v4l2_subdev_state *sd_state,
> >                                 struct
> > v4l2_subdev_frame_interval_enum *fie)
> >
> > --
> > 2.47.1
> >
> >