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

[Rui Miguel Silva <rui.silva@linaro.org>]

Hi Laurent,
On Sun 10 Mar 2019 at 21:48, Laurent Pinchart wrote:
> 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@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.

Yeah, I good point to add support for others subdev's. I will try
to add your comments in a follow up series.

---
Cheers,
	Rui