Re: [PATCH] media: i2c: ov9282: Add test pattern control

[Dave Stevenson]

Hi Xiaolei

On Mon, 16 Mar 2026 at 09:06, Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx> wrote:
>
> This adds V4L2_CID_TEST_PATTERN control support.
>
> Signed-off-by: Xiaolei Wang <xiaolei.wang@xxxxxxxxxxxxx>
> ---
>  drivers/media/i2c/ov9282.c | 47 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> index 2167fb73ea41..f64b2084b8e7 100644
> --- a/drivers/media/i2c/ov9282.c
> +++ b/drivers/media/i2c/ov9282.c
> @@ -104,6 +104,12 @@
>  #define OV9282_REG_STROBE_FRAME_SPAN           CCI_REG32(0x3925)
>  #define OV9282_STROBE_FRAME_SPAN_DEFAULT       0x0000001a
>
> +/* Test Pattern registers */
> +#define OV9282_REG_TEST_PATTERN_BAR    CCI_REG8(0x5e00)
> +#define OV9282_TEST_PATTERN_BAR_EN     BIT(7)
> +#define OV9282_REG_TEST_PATTERN_SOLID  CCI_REG8(0x4320)
> +#define OV9282_TEST_PATTERN_SOLID_EN   BIT(1)
> +
>  /* Input clock rate */
>  #define OV9282_INCLK_RATE      24000000
>
> @@ -462,6 +468,18 @@ static const struct ov9282_mode supported_modes[] = {
>         },
>  };
>
> +enum {
> +       OV9282_TEST_PATTERN_DISABLED,
> +       OV9282_TEST_PATTERN_COLOR_BAR,

This feels like an odd name to choose seeing as it is only a
monochrome sensor so there is no color.

> +       OV9282_TEST_PATTERN_SOLID_COLOR,
> +};
> +
> +static const char * const ov9282_test_pattern_menu[] = {
> +       "Disabled",
> +       "Color Bar",
> +       "Solid Color",
> +};
> +
>  /**
>   * to_ov9282() - ov9282 V4L2 sub-device to ov9282 device.
>   * @subdev: pointer to ov9282 V4L2 sub-device
> @@ -586,6 +604,23 @@ static u32 ov9282_flash_duration_to_us(struct ov9282 *ov9282, u32 value)
>         return DIV_ROUND_UP(value * frame_width, OV9282_STROBE_SPAN_FACTOR);
>  }
>
> +static int ov9282_set_ctrl_test_pattern(struct ov9282 *ov9282, int pattern)
> +{
> +       int ret;
> +
> +       ret = cci_update_bits(ov9282->regmap, OV9282_REG_TEST_PATTERN_BAR,
> +                             OV9282_TEST_PATTERN_BAR_EN,
> +                             pattern == OV9282_TEST_PATTERN_COLOR_BAR ?
> +                             OV9282_TEST_PATTERN_BAR_EN : 0, NULL);

This register is never written from anywhere else, and all the bits
are related to the test pattern, so is there any reason not to set
them all?

> +       if (ret)
> +               return ret;
> +
> +       return cci_update_bits(ov9282->regmap, OV9282_REG_TEST_PATTERN_SOLID,
> +                              OV9282_TEST_PATTERN_SOLID_EN,
> +                              pattern == OV9282_TEST_PATTERN_SOLID_COLOR ?
> +                              OV9282_TEST_PATTERN_SOLID_EN : 0, NULL);

Again no need to use cci_update_bits as all the bits relate to the test pattern.

If you're adding black, then you could add white as well.
Registers 0x4322-0x4329 set the 4 pixel values that would equate to
V4L2_CID_TEST_PATTERN_RED, etc, so writing them all as
CCI_REG16(0x4322, 0x3ff) and repeating for 0x4324, 0x4326, and 0x4328
would give you white.
Then again the only mechanism for implementing that is to use
V4L2_CID_TEST_PATTERN_RED etc, which is rather quirky on a monochrome
sensor. I am thinking that white is more useful than black if you only
implement one.

  Dave

> +}
> +
>  /**
>   * ov9282_set_ctrl() - Set subdevice control
>   * @ctrl: pointer to v4l2_ctrl structure
> @@ -662,6 +697,11 @@ static int ov9282_set_ctrl(struct v4l2_ctrl *ctrl)
>         case V4L2_CID_FLASH_DURATION:
>                 ret = cci_write(ov9282->regmap, OV9282_REG_STROBE_FRAME_SPAN, ctrl->val, NULL);
>                 break;
> +
> +       case V4L2_CID_TEST_PATTERN:
> +               ret = ov9282_set_ctrl_test_pattern(ov9282, ctrl->val);
> +               break;
> +
>         default:
>                 dev_err(ov9282->dev, "Invalid control %d", ctrl->id);
>                 ret = -EINVAL;
> @@ -1242,7 +1282,7 @@ static int ov9282_init_controls(struct ov9282 *ov9282)
>         u32 lpfr;
>         int ret;
>
> -       ret = v4l2_ctrl_handler_init(ctrl_hdlr, 12);
> +       ret = v4l2_ctrl_handler_init(ctrl_hdlr, 13);
>         if (ret)
>                 return ret;
>
> @@ -1314,6 +1354,11 @@ static int ov9282_init_controls(struct ov9282 *ov9282)
>                                   V4L2_CID_FLASH_DURATION, 0, exposure_us, 1,
>                                   OV9282_STROBE_FRAME_SPAN_DEFAULT);
>
> +       v4l2_ctrl_new_std_menu_items(ctrl_hdlr, &ov9282_ctrl_ops,
> +                                    V4L2_CID_TEST_PATTERN,
> +                                    ARRAY_SIZE(ov9282_test_pattern_menu) - 1,
> +                                    0, 0, ov9282_test_pattern_menu);
> +
>         ret = v4l2_fwnode_device_parse(ov9282->dev, &props);
>         if (!ret) {
>                 /* Failure sets ctrl_hdlr->error, which we check afterwards anyway */
> --
> 2.43.0
>