Re: [PATCH 2/3] media: ov5640: add PIXEL_RATE and LINK_FREQ controls

[Maxime Ripard <maxime.ripard@bootlin.com>]

On Fri, Apr 20, 2018 at 04:29:42PM +0200, Daniel Mack wrote:
> Hi,
> 
> On Friday, April 20, 2018 04:15 PM, Maxime Ripard wrote:
> > On Fri, Apr 20, 2018 at 11:44:18AM +0200, Daniel Mack wrote:
> 
> >>  struct ov5640_ctrls {
> >>  	struct v4l2_ctrl_handler handler;
> >> +	struct {
> >> +		struct v4l2_ctrl *link_freq;
> >> +		struct v4l2_ctrl *pixel_rate;
> >> +	};
> >>  	struct {
> >>  		struct v4l2_ctrl *auto_exp;
> >>  		struct v4l2_ctrl *exposure;
> >> @@ -732,6 +752,8 @@ static const struct ov5640_mode_info ov5640_mode_init_data = {
> >>  	.dn_mode	= SUBSAMPLING,
> >>  	.width		= 640,
> >>  	.height		= 480,
> >> +	.pixel_rate	= 27766666,
> >> +	.link_freq_idx	= OV5640_LINK_FREQ_111,
> > 
> > I'm not sure where this is coming from, but on a parallel sensor I
> > have a quite different pixel rate.
> 
> Ah, interesting. What exactly do you mean by 'parallel'? What kind of
> module is that, and what are your pixel rates?

An RGB bus, or MIPI-DPI, or basically a pixel clock + 1 line for each
bit. The sensor can operate using both that bus and a MIPI-CSI2 one.

You have the list of pixel rates in the patch I've linked before:
https://patchwork.linuxtv.org/patch/48710/

There's one pixel sent per clock cycle, so the pixel rate is the same
than the clock rate.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com