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/
> 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+rene...@ragnatech.se>
> Acked-by: Rob Herring <r...@kernel.org>
> ---
> .../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/).
> +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 ...".
> +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 :-)
> +
> +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." ?
> +
> +- 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 ?
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.
> +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@vger.kernel.org
> L: linux-renesas-...@vger.kernel.org
> 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
