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

[Xiaolei Wang <xiaolei.wang@windriver.com>]

Hi Dave,

Thanks for the review.

On 3/17/26 00:38, Dave Stevenson wrote:
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>
> Hi Xiaolei
>
> On Mon, 16 Mar 2026 at 09:06, Xiaolei Wang <xiaolei.wang@windriver.com> wrote:
>> This adds V4L2_CID_TEST_PATTERN control support.
>>
>> Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
>> ---
>>   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.

My mistake, I will correct it to:

enum {
     OV9282_TEST_PATTERN_DISABLED,
     OV9282_TEST_PATTERN_BAR,
     OV9282_TEST_PATTERN_SOLID_WHITE,
};

>
>> +       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?
Agreed
>
>> +       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.
Agreed, will switch to cci_write for both registers.
>
> 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.

That makes sense. I will implement white. If there are no other comments,

I will define these three as you suggested:


enum {
     OV9282_TEST_PATTERN_DISABLED,
     OV9282_TEST_PATTERN_BAR,
     OV9282_TEST_PATTERN_SOLID_WHITE,
};

static const char * const ov9282_test_pattern_menu[] = {
     "Disabled",
     "Bar",
     "Solid White",

};

thanks

xiaolei

>
>    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
>>