[PATCH v4 06/12] media: dt-bindings: add bindings for i.MX7 media driver

[Laurent Pinchart]

Hi Rui,

On Fri, May 18, 2018 at 09:27:58AM +0100, Rui Miguel Silva wrote:
> Hi Sakari,
> Thanks for the review.
> On Fri 18 May 2018 at 06:58, Sakari Ailus wrote:
> > On Thu, May 17, 2018 at 01:50:27PM +0100, Rui Miguel Silva wrote:
> >> Add bindings documentation for i.MX7 media drivers.
> >> 
> >> Signed-off-by: Rui Miguel Silva <rui.silva at linaro.org>
> >> ---
> >>  .../devicetree/bindings/media/imx7.txt        | 145 
> >>  ++++++++++++++++++
> >>  1 file changed, 145 insertions(+)
> >>  create mode 100644 
> >>  Documentation/devicetree/bindings/media/imx7.txt
> >> 
> >> diff --git a/Documentation/devicetree/bindings/media/imx7.txt 
> >> b/Documentation/devicetree/bindings/media/imx7.txt
> >> new file mode 100644
> >> index 000000000000..161cff8e6442
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/media/imx7.txt
> >> @@ -0,0 +1,145 @@
> >> +Freescale i.MX7 Media Video Device
> >> +==================================
> >> +
> >> +Video Media Controller node
> >> +---------------------------
> >
> > Note that DT bindings document the hardware, they are as such 
> > not Linux dependent.
> 
> This was removed in this series, however I removed it in the wrong 
> patch, If you see patch 11/12 you will see this being removed. I will
> fix this in v5. Thanks for notice it.
> 
> >> +
> >> +This is the media controller node for video capture support. 
> >> It is a
> >> +virtual device that lists the camera serial interface nodes 
> >> that the
> >> +media device will control.
> >
> > Ditto.
> >
> >> +
> >> +Required properties:
> >> +- compatible : "fsl,imx7-capture-subsystem";
> >> +- ports      : Should contain a list of phandles pointing to 
> >> camera
> >> +		sensor interface port of CSI
> >> +
> >> +example:
> >> +
> >> +capture-subsystem {
> >
> > What's the purpose of this node, if you only refer to another 
> > device? This one rather does not look like a real device at all.
> >
> >> +	compatible = "fsl,imx7-capture-subsystem";
> >> +	ports = <&csi>;
> >> +};
> >> +
> >> +
> >> +mipi_csi2 node
> >> +--------------
> >> +
> >> +This is the device node for the MIPI CSI-2 receiver core in 
> >> i.MX7 SoC. It is
> >> +compatible with previous version of Samsung D-phy.
> >> +
> >> +Required properties:
> >> +
> >> +- compatible    : "fsl,imx7-mipi-csi2";
> >> +- reg           : base address and length of the register set 
> >> for the device;
> >> +- interrupts    : should contain MIPI CSIS interrupt;
> >> +- clocks        : list of clock specifiers, see
> >> + 
> >> Documentation/devicetree/bindings/clock/clock-bindings.txt for 
> >> details;
> >> +- clock-names   : must contain "pclk", "wrap" and "phy" 
> >> entries, matching
> >> +                  entries in the clock property;
> >> +- power-domains : a phandle to the power domain, see
> >> + 
> >> Documentation/devicetree/bindings/power/power_domain.txt for 
> >> details.
> >> +- reset-names   : should include following entry "mrst";
> >> +- resets        : a list of phandle, should contain reset 
> >> entry of
> >> +                  reset-names;
> >> +- phy-supply    : from the generic phy bindings, a phandle to 
> >> a regulator that
> >> +	          provides power to MIPI CSIS core;
> >> +- bus-width     : maximum number of data lanes supported (SoC 
> >> specific);
> >> +
> >> +Optional properties:
> >> +
> >> +- clock-frequency : The IP's main (system bus) clock frequency 
> >> in Hz, default
> >> +		    value when this property is not specified is 
> >> 166 MHz;
> >> +
> >> +port node
> >> +---------
> >> +
> >> +- reg		  : (required) can take the values 0 or 1, 
> >> where 0 is the
> >> +                     related sink port and port 1 should be 
> >> the source one;
> >> +
> >> +endpoint node
> >> +-------------
> >> +
> >> +- data-lanes    : (required) an array specifying active 
> >> physical MIPI-CSI2
> >> +		    data input lanes and their mapping to logical 
> >> lanes; the
> >> +		    array's content is unused, only its length is 
> >> meaningful;
> >> +
> >> +- fsl,csis-hs-settle : (optional) differential receiver 
> >> (HS-RX) settle time;
> >
> > Could you calculate this, as other drivers do? It probably 
> > changes
> > depending on the device runtime configuration.
> 
> The only reference to possible values to this parameter is given 
> by table in [0], can you point me out the formula for imx7 in the
> documentation?
> 
> [0] https://community.nxp.com/thread/463777

Can't you use the values from that table ? :-) You can get the link
speed by querying the connected subdev and reading its
V4L2_CID_PIXEL_RATE control.

-- 
Regards,

Laurent Pinchart