Re: [PATCH v2] media: ov13858: Correct link-frequency and pixel-rate

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On Sat, Jul 29, 2017 at 12:00:39AM -0700, Chiranjeevi Rapolu wrote:
> Previously both link-frequency and pixel-rate reported by
> the sensor was incorrect, resulting in incorrect FPS.
> Report link-frequency in Hz rather than link data rate in bps.
> Calculate pixel-rate from link-frequency.
> 
> Signed-off-by: Chiranjeevi Rapolu <chiranjeevi.rapolu@xxxxxxxxx>
> ---
> Changes in v2:
> 	- Fix typo, from PLL to PPL.
> 	- Suffixed ULL instead of typecasting to uint64_t
>  drivers/media/i2c/ov13858.c | 28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov13858.c b/drivers/media/i2c/ov13858.c
> index 86550d8..9b87820 100644
> --- a/drivers/media/i2c/ov13858.c
> +++ b/drivers/media/i2c/ov13858.c
> @@ -60,8 +60,8 @@
>  #define OV13858_VBLANK_MIN		56
>  
>  /* HBLANK control - read only */
> -#define OV13858_PPL_540MHZ		2244
> -#define OV13858_PPL_1080MHZ		4488
> +#define OV13858_PPL_270MHZ		2244
> +#define OV13858_PPL_540MHZ		4488
>  
>  /* Exposure control */
>  #define OV13858_REG_EXPOSURE		0x3500
> @@ -944,31 +944,33 @@ struct ov13858_mode {
>  
>  /* Configurations for supported link frequencies */
>  #define OV13858_NUM_OF_LINK_FREQS	2
> -#define OV13858_LINK_FREQ_1080MBPS	1080000000
> -#define OV13858_LINK_FREQ_540MBPS	540000000
> +#define OV13858_LINK_FREQ_540MHZ	540000000ULL
> +#define OV13858_LINK_FREQ_270MHZ	270000000ULL
>  #define OV13858_LINK_FREQ_INDEX_0	0
>  #define OV13858_LINK_FREQ_INDEX_1	1
>  
>  /* Menu items for LINK_FREQ V4L2 control */
>  static const s64 link_freq_menu_items[OV13858_NUM_OF_LINK_FREQS] = {
> -	OV13858_LINK_FREQ_1080MBPS,
> -	OV13858_LINK_FREQ_540MBPS
> +	OV13858_LINK_FREQ_540MHZ,
> +	OV13858_LINK_FREQ_270MHZ
>  };
>  
>  /* Link frequency configs */
>  static const struct ov13858_link_freq_config
>  			link_freq_configs[OV13858_NUM_OF_LINK_FREQS] = {
>  	{
> -		.pixel_rate = 864000000,
> -		.pixels_per_line = OV13858_PPL_1080MHZ,
> +		/* pixel_rate = link_freq * 2 * nr_of_lanes / bits_per_sample */
> +		.pixel_rate = (OV13858_LINK_FREQ_540MHZ * 2 * 4) / 10,

You could calculate the pixel rate at runtime instead. The change should be
done to all mode definitions, not just the two here.

> +		.pixels_per_line = OV13858_PPL_540MHZ,
>  		.reg_list = {
>  			.num_of_regs = ARRAY_SIZE(mipi_data_rate_1080mbps),
>  			.regs = mipi_data_rate_1080mbps,
>  		}
>  	},
>  	{
> -		.pixel_rate = 432000000,
> -		.pixels_per_line = OV13858_PPL_540MHZ,
> +		/* pixel_rate = link_freq * 2 * nr_of_lanes / bits_per_sample */
> +		.pixel_rate = (OV13858_LINK_FREQ_270MHZ * 2 * 4) / 10,
> +		.pixels_per_line = OV13858_PPL_270MHZ,
>  		.reg_list = {
>  			.num_of_regs = ARRAY_SIZE(mipi_data_rate_540mbps),
>  			.regs = mipi_data_rate_540mbps,
> @@ -1634,10 +1636,10 @@ static int ov13858_init_controls(struct ov13858 *ov13858)
>  
>  	ov13858->hblank = v4l2_ctrl_new_std(
>  				ctrl_hdlr, &ov13858_ctrl_ops, V4L2_CID_HBLANK,
> -				OV13858_PPL_1080MHZ - ov13858->cur_mode->width,
> -				OV13858_PPL_1080MHZ - ov13858->cur_mode->width,
> +				OV13858_PPL_540MHZ - ov13858->cur_mode->width,
> +				OV13858_PPL_540MHZ - ov13858->cur_mode->width,
>  				1,
> -				OV13858_PPL_1080MHZ - ov13858->cur_mode->width);
> +				OV13858_PPL_540MHZ - ov13858->cur_mode->width);

You could make use of cur_mode->link_freq_index here.

I'm applying this now, please address these in a follow-up patch.

>  	ov13858->hblank->flags |= V4L2_CTRL_FLAG_READ_ONLY;
>  
>  	ov13858->exposure = v4l2_ctrl_new_std(
> -- 
> 1.9.1
> 

-- 
Sakari Ailus
e-mail: sakari.ailus@xxxxxx	XMPP: sailus@xxxxxxxxxxxxxx



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