linux-kernel - Re: [PATCH v2 12/20] media: i2c: ov4689: Implement vflip/hflip controls

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Date: Fri, 23 Feb 2024 18:21:20 +0300
From: Mikhail Rudenko <mike.rudenko@...il.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org, Laurent
 Pinchart <laurent.pinchart@...asonboard.com>, Jacopo Mondi
 <jacopo@...ndi.org>, Tommaso Merciai <tomm.merciai@...il.com>, Christophe
 JAILLET <christophe.jaillet@...adoo.fr>, Dave Stevenson
 <dave.stevenson@...pberrypi.com>, Mauro Carvalho Chehab
 <mchehab@...nel.org>
Subject: Re: [PATCH v2 12/20] media: i2c: ov4689: Implement vflip/hflip
 controls


Hi Sakari,

and thanks for the review!

On 2024-02-23 at 08:26 GMT, Sakari Ailus <sakari.ailus@...ux.intel.com> wrote:

> Hi Mikhail,
>
> On Mon, Dec 18, 2023 at 08:40:33PM +0300, Mikhail Rudenko wrote:
>> The OV4689 sensor supports horizontal and vertical flipping. Add
>> appropriate controls to the driver. Toggling both array flip and
>> digital flip bits allows to achieve flipping while maintaining output
>> Bayer order. Note that the default value of hflip control corresponds
>> to both bits set, as it was before this patch.
>>
>> Signed-off-by: Mikhail Rudenko <mike.rudenko@...il.com>
>> ---
>>  drivers/media/i2c/ov4689.c | 24 ++++++++++++++++++++++--
>>  1 file changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov4689.c b/drivers/media/i2c/ov4689.c
>> index 06ed9d22b2c8..6cf986bf305d 100644
>> --- a/drivers/media/i2c/ov4689.c
>> +++ b/drivers/media/i2c/ov4689.c
>> @@ -42,6 +42,14 @@
>>  #define OV4689_REG_VTS			CCI_REG16(0x380e)
>>  #define OV4689_VTS_MAX			0x7fff
>>
>> +#define OV4689_REG_TIMING_FORMAT1	CCI_REG8(0x3820)
>> +#define OV4689_REG_TIMING_FORMAT2	CCI_REG8(0x3821)
>> +#define OV4689_TIMING_FLIP_MASK		GENMASK(2, 1)
>> +#define OV4689_TIMING_FLIP_ARRAY	BIT(1)
>> +#define OV4689_TIMING_FLIP_DIGITAL	BIT(2)
>> +#define OV4689_TIMING_FLIP_BOTH		(OV4689_TIMING_FLIP_ARRAY |\
>> +					 OV4689_TIMING_FLIP_DIGITAL)
>> +
>>  #define OV4689_REG_TEST_PATTERN		CCI_REG8(0x5040)
>>  #define OV4689_TEST_PATTERN_ENABLE	0x80
>>  #define OV4689_TEST_PATTERN_DISABLE	0x0
>> @@ -183,7 +191,6 @@ static const struct cci_reg_sequence ov4689_2688x1520_regs[] = {
>>  	{CCI_REG8(0x3811), 0x08}, /* H_WIN_OFF_L h_win_off[7:0] = 0x08*/
>>  	{CCI_REG8(0x3813), 0x04}, /* V_WIN_OFF_L v_win_off[7:0] = 0x04 */
>>  	{CCI_REG8(0x3819), 0x01}, /* VSYNC_END_L vsync_end_point[7:0] = 0x01 */
>> -	{CCI_REG8(0x3821), 0x06}, /* TIMING_FORMAT2 array_h_mirror = 1, digital_h_mirror = 1 */
>>
>>  	/* OTP control */
>>  	{CCI_REG8(0x3d85), 0x36}, /* OTP_REG85 OTP_power_up_load_setting_enable = 1,
>> @@ -607,6 +614,16 @@ static int ov4689_set_ctrl(struct v4l2_ctrl *ctrl)
>>  			  (ctrl->val + ov4689->cur_mode->width) /
>>  			  OV4689_HTS_DIVIDER, &ret);
>>  		break;
>> +	case V4L2_CID_VFLIP:
>> +		cci_update_bits(regmap, OV4689_REG_TIMING_FORMAT1,
>> +				OV4689_TIMING_FLIP_MASK,
>> +				ctrl->val ? OV4689_TIMING_FLIP_BOTH : 0, &ret);
>> +		break;
>> +	case V4L2_CID_HFLIP:
>> +		cci_update_bits(regmap, OV4689_REG_TIMING_FORMAT2,
>> +				OV4689_TIMING_FLIP_MASK,
>> +				ctrl->val ? 0 : OV4689_TIMING_FLIP_BOTH, &ret);
>> +		break;
>>  	default:
>>  		dev_warn(dev, "%s Unhandled id:0x%x, val:0x%x\n",
>>  			 __func__, ctrl->id, ctrl->val);
>> @@ -637,7 +654,7 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
>>
>>  	handler = &ov4689->ctrl_handler;
>>  	mode = ov4689->cur_mode;
>> -	ret = v4l2_ctrl_handler_init(handler, 10);
>> +	ret = v4l2_ctrl_handler_init(handler, 12);
>>  	if (ret)
>>  		return ret;
>>
>> @@ -677,6 +694,9 @@ static int ov4689_initialize_controls(struct ov4689 *ov4689)
>>  				     ARRAY_SIZE(ov4689_test_pattern_menu) - 1,
>>  				     0, 0, ov4689_test_pattern_menu);
>>
>> +	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_VFLIP, 0, 1, 1, 0);
>> +	v4l2_ctrl_new_std(handler, &ov4689_ctrl_ops, V4L2_CID_HFLIP, 0, 1, 1, 0);
>
> Could you take the default value from the mounting rotation?

Could you provide an example (maybe a link to an existing driver) which
does this right? If I understand you correctly, I should flip default
for both flip controls for 180 degree rotation. But what should I do for
90, 270 and all the rest rotation values?

> The default should be upside-up, but this is an existing driver and
> changing the flipping now could affect existing users.

Do you mean default rotation value when missing device tree property?

> <URL:https://hverkuil.home.xs4all.nl/spec/userspace-api/drivers/camera-sensor.html#rotation-orientation-and-flipping>
>



>> +
>>  	if (handler->error) {
>>  		ret = handler->error;
>>  		dev_err(ov4689->dev, "Failed to init controls(%d)\n", ret);


--
Best regards,
Mikhail Rudenko