Re: [PATCH v2 1/2] media: i2c: ov13b10: Fix h_blank calculation

[Hao Yao <hao.yao@intel.com>]

Hi Hans,

On 2025/3/11 18:20, Hans de Goede wrote:
> Hi Hao,
> 
> On 11-Mar-25 9:46 AM, Hao Yao wrote:
>> Pixel per line (PPL) is calculated as pixel_rate / (VTS * FPS), which
>> is not decided by MIPI CSI-2 link frequency. PPL can vary while link
>> frequency keeps the same. If PPL is wrong, the h_blank = PPL - width
>> is also wrong then FPS control is inaccurate.
>>
>> This patch fix h_blank by:
>> 1. Move PPL from link_freq_config to ov13b10_mode
>> 2. Add PPL value for different modes
>> 3. Use PPL from mode to calculate h_blank
>>
>> Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
>> Signed-off-by: Hao Yao <hao.yao@intel.com>
>> ---
>>   drivers/media/i2c/ov13b10.c | 36 ++++++++++++++++++------------------
>>   1 file changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov13b10.c b/drivers/media/i2c/ov13b10.c
>> index 73c844aa5697..2e83fc23f321 100644
>> --- a/drivers/media/i2c/ov13b10.c
>> +++ b/drivers/media/i2c/ov13b10.c
>> @@ -34,9 +34,6 @@
>>   #define OV13B10_VTS_120FPS		0x0320
>>   #define OV13B10_VTS_MAX			0x7fff
>>   
>> -/* HBLANK control - read only */
>> -#define OV13B10_PPL_560MHZ		4704
>> -
>>   /* Exposure control */
>>   #define OV13B10_REG_EXPOSURE		0x3500
>>   #define OV13B10_EXPOSURE_MIN		4
>> @@ -95,7 +92,7 @@ struct ov13b10_reg_list {
>>   
>>   /* Link frequency config */
>>   struct ov13b10_link_freq_config {
>> -	u32 pixels_per_line;
>> +	u64 link_freq;
>>   
>>   	/* registers for this link frequency */
>>   	struct ov13b10_reg_list reg_list;
>> @@ -114,6 +111,10 @@ struct ov13b10_mode {
>>   
>>   	/* Index of Link frequency config to be used */
>>   	u32 link_freq_index;
>> +
>> +	/* Pixels per line in current mode */
>> +	u32 ppl;
>> +
>>   	/* Default register values */
>>   	struct ov13b10_reg_list reg_list;
>>   };
>> @@ -549,7 +550,7 @@ static const s64 link_freq_menu_items[] = {
>>   static const struct ov13b10_link_freq_config
>>   			link_freq_configs[] = {
>>   	{
>> -		.pixels_per_line = OV13B10_PPL_560MHZ,
>> +		.link_freq = OV13B10_LINK_FREQ_560MHZ,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mipi_data_rate_1120mbps),
>>   			.regs = mipi_data_rate_1120mbps,
>> @@ -564,6 +565,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.height = 3120,
>>   		.vts_def = OV13B10_VTS_30FPS,
>>   		.vts_min = OV13B10_VTS_30FPS,
>> +		.ppl = 4704,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_4208x3120_regs),
>>   			.regs = mode_4208x3120_regs,
>> @@ -575,6 +577,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.height = 3120,
>>   		.vts_def = OV13B10_VTS_30FPS,
>>   		.vts_min = OV13B10_VTS_30FPS,
>> +		.ppl = 4704,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_4160x3120_regs),
>>   			.regs = mode_4160x3120_regs,
>> @@ -586,6 +589,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.height = 2340,
>>   		.vts_def = OV13B10_VTS_30FPS,
>>   		.vts_min = OV13B10_VTS_30FPS,
>> +		.ppl = 4704,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_4160x2340_regs),
>>   			.regs = mode_4160x2340_regs,
>> @@ -597,6 +601,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.height = 1560,
>>   		.vts_def = OV13B10_VTS_60FPS,
>>   		.vts_min = OV13B10_VTS_60FPS,
>> +		.ppl = 4704,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_2104x1560_regs),
>>   			.regs = mode_2104x1560_regs,
>> @@ -608,6 +613,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.height = 1170,
>>   		.vts_def = OV13B10_VTS_60FPS,
>>   		.vts_min = OV13B10_VTS_60FPS,
>> +		.ppl = 4704,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_2080x1170_regs),
>>   			.regs = mode_2080x1170_regs,
>> @@ -620,6 +626,7 @@ static const struct ov13b10_mode supported_modes[] = {
>>   		.vts_def = OV13B10_VTS_120FPS,
>>   		.vts_min = OV13B10_VTS_120FPS,
>>   		.link_freq_index = OV13B10_LINK_FREQ_INDEX_0,
>> +		.ppl = 4664,
>>   		.reg_list = {
>>   			.num_of_regs = ARRAY_SIZE(mode_1364x768_120fps_regs),
>>   			.regs = mode_1364x768_120fps_regs,
>> @@ -1062,19 +1069,13 @@ ov13b10_set_pad_format(struct v4l2_subdev *sd,
>>   		__v4l2_ctrl_s_ctrl_int64(ov13b->pixel_rate, pixel_rate);
>>   
>>   		/* Update limits and set FPS to default */
>> -		vblank_def = ov13b->cur_mode->vts_def -
>> -			     ov13b->cur_mode->height;
>> -		vblank_min = ov13b->cur_mode->vts_min -
>> -			     ov13b->cur_mode->height;
>> +		vblank_def = mode->vts_def - mode->height;
>> +		vblank_min = mode->vts_min - mode->height;
>>   		__v4l2_ctrl_modify_range(ov13b->vblank, vblank_min,
>> -					 OV13B10_VTS_MAX
>> -					 - ov13b->cur_mode->height,
>> -					 1,
>> -					 vblank_def);
>> +					 OV13B10_VTS_MAX - mode->height,
>> +					 1, vblank_def);
>>   		__v4l2_ctrl_s_ctrl(ov13b->vblank, vblank_def);
>> -		h_blank =
>> -			link_freq_configs[mode->link_freq_index].pixels_per_line
>> -			 - ov13b->cur_mode->width;
>> +		h_blank = mode->ppl - mode->width;
>>   		__v4l2_ctrl_modify_range(ov13b->hblank, h_blank,
>>   					 h_blank, 1, h_blank);
>>   	}
> 
> You are doing a bunch of unrelated search 'ov13b->cur_mode->' replace
> with 'mode->' here e.g. for vblank_def and vblank_min. While this is
> a good change to have which increases readability, this is unrelated
> to the hblank changes, so please split this out into a new patch 1/3
> as preparation for the further changes in the series.
> 
> Mixing those changes into this patch makes it hard for reviewers to
> see which changes you are actually making wrt h_blank handling.
> 
> Regards,
> 
> Hans
> 

Sorry for that - let me fix it in next version. This patchset was mainly 
for the 2 lane setting of ov13b, and the style change is not necessary.

Best Regards,
Hao Yao

> 
>> @@ -1328,8 +1329,7 @@ static int ov13b10_init_controls(struct ov13b10 *ov13b)
>>   					  OV13B10_VTS_MAX - mode->height, 1,
>>   					  vblank_def);
>>   
>> -	hblank = link_freq_configs[mode->link_freq_index].pixels_per_line -
>> -		 mode->width;
>> +	hblank = mode->ppl - mode->width;
>>   	ov13b->hblank = v4l2_ctrl_new_std(ctrl_hdlr, &ov13b10_ctrl_ops,
>>   					  V4L2_CID_HBLANK,
>>   					  hblank, hblank, 1, hblank);
>