Hi Laurent,
Thanks for your comments.
On 2017-12-11 20:00:21 +0200, Laurent Pinchart wrote:
> Hi Niklas,
>
> Thank you for the patch.
>
> On Wednesday, 29 November 2017 21:32:34 EET Niklas Söderlund wrote:
> > Documentation for Renesas R-Car MIPI CSI-2 receiver. The CSI-2 receivers
> > are located between the video sources (CSI-2 transmitters) and the video
> > grabbers (VIN) on Gen3 of Renesas R-Car SoC.
> >
> > Each CSI-2 device is connected to more then one VIN device which
>
> s/then/than/
>
> > simultaneously can receive video from the same CSI-2 device. Each VIN
> > device can also be connected to more then one CSI-2 device. The routing
>
> s/then/than/
>
> > of which link are used are controlled by the VIN devices. There are only
>
> s/link are/links are/ or s/link are/link is/
> s/are controlled/is controlled/
>
> > a few possible routes which are set by hardware limitations, which are
> > different for each SoC in the Gen3 family.
> >
> > To work with the limitations of routing possibilities it is necessary
> > for the DT bindings to describe which VIN device is connected to which
> > CSI-2 device. This is why port 1 needs to to assign reg numbers for each
> > VIN device that be connected to it. To setup and to know which links are
>
> s/that be/that is/
I agree with all spelling fixes above, will fix for next version,
thanks.
>
> > valid for each SoC is the responsibility of the VIN driver since the
> > register to configure it belongs to the VIN hardware.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > Acked-by: Rob Herring <robh@xxxxxxxxxx>
> > ---
> > .../bindings/media/renesas,rcar-csi2.txt | 105 ++++++++++++++++++
> > MAINTAINERS | 1 +
> > 2 files changed, 106 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt
> >
> > diff --git a/Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt
> > b/Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt new file
> > mode 100644
> > index 0000000000000000..688afd83bf66f8cf
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt
> > @@ -0,0 +1,105 @@
> > +Renesas R-Car MIPI CSI-2
> > +------------------------
> > +
> > +The rcar-csi2 device provides MIPI CSI-2 capabilities for the Renesas R-Car
>
> rcar-csi2 is the name of the driver, I would call it the "R-Car CSI-2 receiver
> device" (or s/device/IP core/).
Yes "R-Car CSI-2 receiver device" sounds better.
>
> > +family of devices. It is to be used in conjunction with the R-Car VIN
> > module,
>
> The IP core itself doesn't have to be used with the VIN, but in R-Car SoCs it
> is, so I would phrase it as "It is used ...".
Agreed.
>
> > +which provides the video capture capabilities.
> > +
> > +Mandatory properties
> > +--------------------
> > + - compatible: Must be one or more of the following
> > + - "renesas,r8a7795-csi2" for the R8A7795 device.
> > + - "renesas,r8a7796-csi2" for the R8A7796 device.
> > +
> > + - reg: the register base and size for the device registers
> > + - interrupts: the interrupt for the device
> > + - clocks: Reference to the parent clock
>
> Either capitalize the first word after the colon or don't, but please don't
> mix them :-)
It's this not the new thing after camel case, mixed camel case notation?
Yes looks terrible will fix for next version.
>
> > +
> > +The device node shall contain two 'port' child nodes according to the
> > +bindings defined in Documentation/devicetree/bindings/media/
> > +video-interfaces.txt. Port 0 shall connect the node that is the video
> > +source for to the CSI-2.
>
> Or simply "Port 0 shall connect to the CSI-2 source." ?
>
> > Port 1 shall connect all the R-Car VIN
> > +modules, which can make use of the CSI-2 module.
>
> And to be a bit more explicit, how about "Port 1 shall connect to all the R-
> Car VIN modules that have a hardware connection to the CSI-2 receiver." ?
The descriptions you provide are better, will use them in the next
version. Thanks!
>
> > +
> > +- Port 0 - Video source (Mandatory)
>
> Nitpicking, I don't think you need to capitalize Mandatory.
:-)
>
> > + - Endpoint 0 - sub-node describing the endpoint that is the video source
> > +
> > +- Port 1 - VIN instances (Mandatory for all VIN present in the SoC)
> > + - Endpoint 0 - sub-node describing the endpoint that is VIN0
> > + - Endpoint 1 - sub-node describing the endpoint that is VIN1
> > + - Endpoint 2 - sub-node describing the endpoint that is VIN2
> > + - Endpoint 3 - sub-node describing the endpoint that is VIN3
> > + - Endpoint 4 - sub-node describing the endpoint that is VIN4
> > + - Endpoint 5 - sub-node describing the endpoint that is VIN5
> > + - Endpoint 6 - sub-node describing the endpoint that is VIN6
> > + - Endpoint 7 - sub-node describing the endpoint that is VIN7
>
> Should we clarify that only a subset of those endpoints shall be present when
> the CSI-2 receiver isn't connected to all VIN instances ?
Yes. In fact I think this should simply be marked as optional. As it is
valid to omit a VIN from this as it is possible to use some VIN not only
with a CSI-2 source but with a parallel input.
Will mark all options in port 1 as optional in next version.
>
> Furthermore, as explained in a comment I made when reviewing the VIN patch
> series, I wonder whether we shouldn't identify the CSI-2 receiver instances by
> ID the same way we do with the VIN instances (using the renesas,id property).
> In that case I think the endpoint numbering won't matter.
The endpoint numbering here plays no part in identify the CSI-2 receiver
instances nor dose it carry any other information. I still think it's
neat to define the binding like this as it more explicit and IMHO this
makes it easier to understand.
>
> > +Example:
> > +
> > + csi20: csi2@fea80000 {
> > + compatible = "renesas,r8a7796-csi2";
> > + reg = <0 0xfea80000 0 0x10000>;
> > + interrupts = <0 184 IRQ_TYPE_LEVEL_HIGH>;
> > + clocks = <&cpg CPG_MOD 714>;
> > + power-domains = <&sysc R8A7796_PD_ALWAYS_ON>;
> > + resets = <&cpg 714>;
> > +
> > + ports {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + port@0 {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + reg = <0>;
> > +
> > + csi20_in: endpoint@0 {
> > + reg = <0>;
> > + clock-lanes = <0>;
> > + data-lanes = <1>;
> > + remote-endpoint = <&adv7482_txb>;
> > + };
> > + };
> > +
> > + port@1 {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + reg = <1>;
> > +
> > + csi20vin0: endpoint@0 {
> > + reg = <0>;
> > + remote-endpoint = <&vin0csi20>;
> > + };
> > + csi20vin1: endpoint@1 {
> > + reg = <1>;
> > + remote-endpoint = <&vin1csi20>;
> > + };
> > + csi20vin2: endpoint@2 {
> > + reg = <2>;
> > + remote-endpoint = <&vin2csi20>;
> > + };
> > + csi20vin3: endpoint@3 {
> > + reg = <3>;
> > + remote-endpoint = <&vin3csi20>;
> > + };
> > + csi20vin4: endpoint@4 {
> > + reg = <4>;
> > + remote-endpoint = <&vin4csi20>;
> > + };
> > + csi20vin5: endpoint@5 {
> > + reg = <5>;
> > + remote-endpoint = <&vin5csi20>;
> > + };
> > + csi20vin6: endpoint@6 {
> > + reg = <6>;
> > + remote-endpoint = <&vin6csi20>;
> > + };
> > + csi20vin7: endpoint@7 {
> > + reg = <7>;
> > + remote-endpoint = <&vin7csi20>;
> > + };
> > + };
> > + };
> > + };
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index aa71ab52fd76d160..4737de9f41bff570 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -8652,6 +8652,7 @@ L: linux-media@xxxxxxxxxxxxxxx
> > L: linux-renesas-soc@xxxxxxxxxxxxxxx
> > T: git git://linuxtv.org/media_tree.git
> > S: Supported
> > +F: Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt
> > F: Documentation/devicetree/bindings/media/rcar_vin.txt
> > F: drivers/media/platform/rcar-vin/
>
> --
> Regards,
>
> Laurent Pinchart
>
--
Regards,
Niklas Söderlund
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