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:

quoted

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/

quoted

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/

quoted

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/

quoted

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.

quoted

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 <redacted>
Acked-by: Rob Herring <redacted>
---
 .../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.

quoted

+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.

quoted

+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.

quoted

+
+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." ?

quoted

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!

quoted

+
+- Port 0 - Video source (Mandatory)

Nitpicking, I don't think you need to capitalize Mandatory.

:-)

quoted

+	- 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.

quoted

+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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
 L:	linux-renesas-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.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

-- 
Regards,
Niklas Söderlund
--
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