Re: [PATCH 08/13] media: i2c: imx214: Add vblank and hblank controls

From: Dave Stevenson
Date: Thu Sep 12 2024 - 10:52:05 EST

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Hi André & Ricardo

On Thu, 12 Sept 2024 at 14:41, Ricardo Ribalda Delgado
<ribalda@xxxxxxxxxx> wrote:
>
> Hi
>
> Arent you missing some chage in enum_frame_interval?

Raw sensors shouldn't be using [enum|set|get]_frame_interval at all
https://www.kernel.org/doc/html/latest/userspace-api/media/drivers/camera-sensor.html#frame-interval-configuration

The question now is how to handle the backwards compatibility for any
userspace app that might be using this driver and expecting to use the
frame_interval calls.
Seeing as it only ever allowed a fixed value of 30fps, leaving it as
is with a comment as to why it is there would be reasonable in my
view.

> On Mon, Sep 2, 2024 at 11:53 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 | 112 ++++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 91 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/media/i2c/imx214.c b/drivers/media/i2c/imx214.c
> > index 3b422cddbdce..9f5a57aebb86 100644
> > --- a/drivers/media/i2c/imx214.c
> > +++ b/drivers/media/i2c/imx214.c
> > @@ -34,11 +34,18 @@
> >
> > /* V-TIMING internal */
> > #define IMX214_REG_FRM_LENGTH_LINES CCI_REG16(0x0340)
> > +#define IMX214_VTS_MAX 0xffff
> > +
> > +#define IMX214_VBLANK_MIN 4
> > +
> > +/* 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_MAX (IMX214_VTS_MAX - IMX214_EXPOSURE_OFFSET)
> > #define IMX214_EXPOSURE_STEP 1
> > #define IMX214_EXPOSURE_DEFAULT 3184
> > #define IMX214_REG_EXPOSURE_RATIO CCI_REG8(0x0222)
> > @@ -189,6 +196,8 @@ 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;
> >
> > @@ -205,8 +214,6 @@ 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 },
> > @@ -277,8 +284,6 @@ 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 },
> > @@ -362,6 +367,7 @@ 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 },
> > @@ -465,18 +471,24 @@ 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,
> > },
> > @@ -629,6 +641,37 @@ static int imx214_set_format(struct v4l2_subdev *sd,
> > __crop->width = mode->width;
> > __crop->height = mode->height;
> >
> > + if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
> > + int exposure_max;
> > + int exposure_def;
> > + int hblank;
> > +
> > + /* Update limits and set FPS to default */
> > + __v4l2_ctrl_modify_range(imx214->vblank, IMX214_VBLANK_MIN,
> > + IMX214_VTS_MAX - mode->height, 1,
> > + mode->vts_def - mode->height);
> > + __v4l2_ctrl_s_ctrl(imx214->vblank,
> > + mode->vts_def - mode->height);
> > +
> > + /* Update max exposure while meeting expected vblanking */
> > + exposure_max = mode->vts_def - IMX214_EXPOSURE_OFFSET;
> > + exposure_def = (exposure_max < IMX214_EXPOSURE_DEFAULT) ?
> > + 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 changeble 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 +721,25 @@ 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;
> >
> > + state = v4l2_subdev_get_locked_active_state(&imx214->sd);
> > + format = v4l2_subdev_state_get_format(state, 0);
> > +
> > + if (ctrl->id == V4L2_CID_VBLANK) {
> > + int exposure_max, exposure_def;
> > +
> > + /* 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 +751,10 @@ 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:
> > + cci_write(imx214->regmap, IMX214_REG_FRM_LENGTH_LINES,
> > + format->height + ctrl->val, &ret);

My datasheet says this register is "set up in multiples of 2".
(LINE_LENGTH_PCK for HBLANK is "set in multiples of 8")

I don't have one of these modules, but is that saying only multiples
of 2 are permitted (in which case the step size for the control needs
to reflect that), or that setting a value of N is interpreted by the
hardware as 2N?
Do all the numbers with PIXEL_RATE work out correctly in the frame rate calcs?

Reading the spec sheet that 30fps is the max frame rate at full res
(4096x2304), and the driver was setting a value of 3194 to this
register, I don't see it being interpreted as 2N. Then again having
VBLANK at 890 seems pretty high.

> > + break;
> > default:
> > ret = -EINVAL;
> > }
> > @@ -714,8 +777,11 @@ 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 +789,7 @@ 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;
> >
> > @@ -739,22 +805,26 @@ static int imx214_ctrls_init(struct imx214 *imx214)
> > if (imx214->link_freq)
> > imx214->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> >
> > - /*
> > - * WARNING!
> > - * Values obtained reverse engineering blobs and/or devices.
> > - * Ranges and functionality might be wrong.
> > - *
> > - * Sony, please release some register set documentation for the
> > - * device.
> > - *
> > - * Yours sincerely, Ricardo.
> > - */
>
> I would like to keep this comment until there is a public document available.

I suspect you'll be waiting forever for a document to be officially released.

I have a datasheet for IMX214, and I believe Kieran and Jacopo do too.
Which specific values do you wish to be verified?

>
> > + /* 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_VBLANK_MIN being 4 feels plausible, but pretty low.
I read the datasheet to say there are 4 embedded data lines per image.
Seeing as you have STATS data output enabled as well that makes 5
lines of non-image data per frame, but you're only adding blanking
time for 4 lines.

As noted above, I think you've also increased the max frame rate
significantly above that quoted by Sony. Has that been actually
exercised and confirmed to function correctly?

Dave

> > + IMX214_VTS_MAX - mode->height, 1,
> > + 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,
> > IMX214_EXPOSURE_STEP,
> > - IMX214_EXPOSURE_DEFAULT);
> > + exposure_def);
> >
> > imx214->unit_size = v4l2_ctrl_new_std_compound(ctrl_hdlr,
> > NULL,
> >
> > --
> > 2.46.0
> >
> >
>

Next message: Dan Carpenter: "Re: [PATCH] ALSA: control: prevent some integer overflow issues"
Previous message: Lee Jones: "Re: (subset) [PATCH v7 00/16] Add audio support for the MediaTek Genio 350-evk board"
In reply to: Ricardo Ribalda Delgado: "Re: [PATCH 08/13] media: i2c: imx214: Add vblank and hblank controls"
Next in thread: Dave Stevenson: "Re: [PATCH 08/13] media: i2c: imx214: Add vblank and hblank controls"
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