Re: [PATCH v3 06/24] ARM: dts: imx6-sabrelite: add OV5642 and OV5640 camera sensors

[Laurent Pinchart]

Hi Russell,

On Monday 30 Jan 2017 22:51:33 Russell King - ARM Linux wrote:
> On Fri, Jan 06, 2017 at 06:11:24PM -0800, Steve Longerbeam wrote:
> > +	ov5640: camera@40 {
> > +		compatible = "ovti,ov5640";
> > +		pinctrl-names = "default";
> > +		pinctrl-0 = <&pinctrl_ov5640>;
> > +		clocks = <&mipi_xclk>;
> > +		clock-names = "xclk";
> > +		reg = <0x40>;
> > +		xclk = <22000000>;
> > +		reset-gpios = <&gpio2 5 GPIO_ACTIVE_LOW>; /* NANDF_D5 */
> > +		pwdn-gpios = <&gpio6 9 GPIO_ACTIVE_HIGH>; /* NANDF_WP_B */
> > +
> > +		port {
> > +			#address-cells = <1>;
> > +			#size-cells = <0>;
> > +
> > +			ov5640_to_mipi_csi: endpoint@1 {
> > +				reg = <1>;
> > +				remote-endpoint = 
<&mipi_csi_from_mipi_sensor>;
> > +				data-lanes = <0 1>;
> > +				clock-lanes = <2>;
> 
> How do you envision a four-lane sensor being described?
> 
> 	data-lanes = <0 1 3 4>;
> 	clock-lanes = <2>;
> 
> ?
> 
> The binding document for video-interfaces.txt says:
> 
> - clock-lanes: an array of physical clock lane indexes. Position of an entry
> determines the logical lane number, while the value of an entry indicates
> physical lane, e.g. for a MIPI CSI-2 bus we could have "clock-lanes =
> <0>;", which places the clock lane on hardware lane 0. This property is
> valid for serial busses only (e.g. MIPI CSI-2). Note that for the MIPI
> CSI-2 bus this array contains only one entry.
> 
> So I think you need to have a good reason to make the clock lane non-zero.

The purpose of the data-lanes and clock-lanes properties is to describe lane 
assignment for hardware that supports lane routing. As far as I know the 
OV5640 doesn't support lane routing and has dedicated pins for the clock and 
data lanes. The data-lanes and clock-lanes properties should probably not be 
specified at all.

-- 
Regards,

Laurent Pinchart