Re: [PATCH v7 1/2] media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver documentation

[Niklas Söderlund]

Hi Sakari,

On 2017-06-14 13:45:58 +0300, Sakari Ailus wrote:
> Hi Niklas,
> 
> On Tue, Jun 13, 2017 at 06:50:14PM +0200, Niklas Söderlund wrote:
> > Hi Sakari,
> > 
> > Thanks for your feedback.
> > 
> > On 2017-05-29 14:16:25 +0300, Sakari Ailus wrote:
> > > Hi Niklas,
> > > 
> > > On Wed, May 24, 2017 at 02:13:52AM +0200, Niklas Söderlund wrote:
> > > > From: Niklas Söderlund 
> > > > 
> > > > 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
> > > > 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
> > > > of which link are used are controlled by the VIN devices. There are only
> > > > 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
> > > > 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 
> > > > ---
> > > >  .../devicetree/bindings/media/rcar-csi2.txt| 116 
> > > > +
> > > >  1 file changed, 116 insertions(+)
> > > >  create mode 100644 
> > > > Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/media/rcar-csi2.txt 
> > > > b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > > new file mode 100644
> > > > index ..f6e2027ee92b171a
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > > @@ -0,0 +1,116 @@
> > > > +Renesas R-Car MIPI CSI-2
> > > > +
> > > > +
> > > > +The rcar-csi2 device provides MIPI CSI-2 capabilities for the Renesas 
> > > > R-Car
> > > > +family of devices. It is to be used in conjunction with the R-Car VIN 
> > > > module,
> > > > +which provides the video capture capabilities.
> > > > +
> > > > + - compatible: Must be one or more of the following
> > > > +   - "renesas,r8a7795-csi2" for the R8A7795 device.
> > > > +   - "renesas,r8a7796-csi2" for the R8A7796 device.
> > > > +   - "renesas,rcar-gen3-csi2" for a generic R-Car Gen3 compatible 
> > > > device.
> > > > +
> > > > +   When compatible with a generic version nodes must list the
> > > > +   SoC-specific version corresponding to the platform first
> > > > +   followed by the generic version.
> > > > +
> > > > + - reg: the register base and size for the device registers
> > > > + - interrupts: the interrupt for the device
> > > > + - clocks: Reference to the parent clock
> > > > +
> > > > +The device node should contain two 'port' child nodes according to the
> > > > +bindings defined in Documentation/devicetree/bindings/media/
> > > > +video-interfaces.txt. Port 0 should connect the node that is the video
> > > > +source for to the CSI-2. Port 1 should connect all the R-Car VIN
> > > > +modules, which can make use of the CSI-2 module.
> > > 
> > > Should or shall?
> > > 
> > > I guess you could add that it is possible to leave them unconnected, too.
> > 
> > Which ports/endpoints are you talking about? In my mind it's not allowed 
> > to leave them unconnected.
> > 
> > If there ever is a system with only 4 VIN instances (I'm not aware of 
> > any such system) then yes the endpoints for those VIN not present in the 
> > system in port 1 should be left unconnected but other then that they 
> > should all be mandatory right? Or am I missing something?
> 
> I think so, yes. Then "shall" is right, isn't it?

Yes shall is then the correct term, will update for next version.

> 
> > 
> > > 
> > > > +
> > > > +- Port 0 - Video source
> > > > +   - Reg 0 - sub-node describing the endpoint that is the video 
> > > > source
> > > 
> > > Which endpoint properties are mandatory for the receiver? Which ones are
> > > optional? (I.e. it shouldn't be necessary to read driver code to write 
> > > board
> > > description.)
> > 
> > I will add a note that all endpoints in port 0 are mandatory and that 
> > all endpoints that represents a connection to a VIN instance in the 
> > system is mandatory for next version. Thanks I did not think about this 
> > possibility.
> 
> Please list the mandatory and optional properties, too. Not just the
> endpoints.

Good point, will do so.

> 
> -- 
> Hälsningar,
> 
> Sakari Ailus
> 

Re: [PATCH v7 1/2] media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver documentation

[Sakari Ailus]

Hi Niklas,

On Tue, Jun 13, 2017 at 06:50:14PM +0200, Niklas Söderlund wrote:
> Hi Sakari,
> 
> Thanks for your feedback.
> 
> On 2017-05-29 14:16:25 +0300, Sakari Ailus wrote:
> > Hi Niklas,
> > 
> > On Wed, May 24, 2017 at 02:13:52AM +0200, Niklas Söderlund wrote:
> > > From: Niklas Söderlund 
> > > 
> > > 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
> > > 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
> > > of which link are used are controlled by the VIN devices. There are only
> > > 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
> > > 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 
> > > ---
> > >  .../devicetree/bindings/media/rcar-csi2.txt| 116 
> > > +
> > >  1 file changed, 116 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > 
> > > diff --git a/Documentation/devicetree/bindings/media/rcar-csi2.txt 
> > > b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > new file mode 100644
> > > index ..f6e2027ee92b171a
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> > > @@ -0,0 +1,116 @@
> > > +Renesas R-Car MIPI CSI-2
> > > +
> > > +
> > > +The rcar-csi2 device provides MIPI CSI-2 capabilities for the Renesas 
> > > R-Car
> > > +family of devices. It is to be used in conjunction with the R-Car VIN 
> > > module,
> > > +which provides the video capture capabilities.
> > > +
> > > + - compatible: Must be one or more of the following
> > > +   - "renesas,r8a7795-csi2" for the R8A7795 device.
> > > +   - "renesas,r8a7796-csi2" for the R8A7796 device.
> > > +   - "renesas,rcar-gen3-csi2" for a generic R-Car Gen3 compatible device.
> > > +
> > > +   When compatible with a generic version nodes must list the
> > > +   SoC-specific version corresponding to the platform first
> > > +   followed by the generic version.
> > > +
> > > + - reg: the register base and size for the device registers
> > > + - interrupts: the interrupt for the device
> > > + - clocks: Reference to the parent clock
> > > +
> > > +The device node should contain two 'port' child nodes according to the
> > > +bindings defined in Documentation/devicetree/bindings/media/
> > > +video-interfaces.txt. Port 0 should connect the node that is the video
> > > +source for to the CSI-2. Port 1 should connect all the R-Car VIN
> > > +modules, which can make use of the CSI-2 module.
> > 
> > Should or shall?
> > 
> > I guess you could add that it is possible to leave them unconnected, too.
> 
> Which ports/endpoints are you talking about? In my mind it's not allowed 
> to leave them unconnected.
> 
> If there ever is a system with only 4 VIN instances (I'm not aware of 
> any such system) then yes the endpoints for those VIN not present in the 
> system in port 1 should be left unconnected but other then that they 
> should all be mandatory right? Or am I missing something?

I think so, yes. Then "shall" is right, isn't it?

> 
> > 
> > > +
> > > +- Port 0 - Video source
> > > + - Reg 0 - sub-node describing the endpoint that is the video source
> > 
> > Which endpoint properties are mandatory for the receiver? Which ones are
> > optional? (I.e. it shouldn't be necessary to read driver code to write board
> > description.)
> 
> I will add a note that all endpoints in port 0 are mandatory and that 
> all endpoints that represents a connection to a VIN instance in the 
> system is mandatory for next version. Thanks I did not think about this 
> possibility.

Please list the mandatory and optional properties, too. Not just the
endpoints.

-- 
Hälsningar,

Sakari Ailus
e-mail: sakari.ai...@iki.fi XMPP: sai...@retiisi.org.uk

Re: [PATCH v7 1/2] media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver documentation

[Sakari Ailus]

Hi Niklas,

On Wed, May 24, 2017 at 02:13:52AM +0200, Niklas Söderlund wrote:
> From: Niklas Söderlund 
> 
> 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
> 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
> of which link are used are controlled by the VIN devices. There are only
> 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
> 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 
> ---
>  .../devicetree/bindings/media/rcar-csi2.txt| 116 
> +
>  1 file changed, 116 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/rcar-csi2.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/rcar-csi2.txt 
> b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> new file mode 100644
> index ..f6e2027ee92b171a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/rcar-csi2.txt
> @@ -0,0 +1,116 @@
> +Renesas R-Car MIPI CSI-2
> +
> +
> +The rcar-csi2 device provides MIPI CSI-2 capabilities for the Renesas R-Car
> +family of devices. It is to be used in conjunction with the R-Car VIN module,
> +which provides the video capture capabilities.
> +
> + - compatible: Must be one or more of the following
> +   - "renesas,r8a7795-csi2" for the R8A7795 device.
> +   - "renesas,r8a7796-csi2" for the R8A7796 device.
> +   - "renesas,rcar-gen3-csi2" for a generic R-Car Gen3 compatible device.
> +
> +   When compatible with a generic version nodes must list the
> +   SoC-specific version corresponding to the platform first
> +   followed by the generic version.
> +
> + - reg: the register base and size for the device registers
> + - interrupts: the interrupt for the device
> + - clocks: Reference to the parent clock
> +
> +The device node should contain two 'port' child nodes according to the
> +bindings defined in Documentation/devicetree/bindings/media/
> +video-interfaces.txt. Port 0 should connect the node that is the video
> +source for to the CSI-2. Port 1 should connect all the R-Car VIN
> +modules, which can make use of the CSI-2 module.

Should or shall?

I guess you could add that it is possible to leave them unconnected, too.

> +
> +- Port 0 - Video source
> + - Reg 0 - sub-node describing the endpoint that is the video source

Which endpoint properties are mandatory for the receiver? Which ones are
optional? (I.e. it shouldn't be necessary to read driver code to write board
description.)

> +
> +- Port 1 - VIN instances
> + - Reg 0 - sub-node describing the endpoint that is VIN0
> + - Reg 1 - sub-node describing the endpoint that is VIN1
> + - Reg 2 - sub-node describing the endpoint that is VIN2
> + - Reg 3 - sub-node describing the endpoint that is VIN3
> + - Reg 4 - sub-node describing the endpoint that is VIN4
> + - Reg 5 - sub-node describing the endpoint that is VIN5
> + - Reg 6 - sub-node describing the endpoint that is VIN6
> + - Reg 7 - sub-node describing the endpoint that is VIN7
> +
> +Example:
> +
> +/* SoC properties */
> +
> +  csi20: csi2@fea8 {
> +  compatible = "renesas,r8a7796-csi2";
> +  reg = <0 0xfea8 0 0x1>;
> +  interrupts = <0 184 IRQ_TYPE_LEVEL_HIGH>;
> +  clocks = < CPG_MOD 714>;
> +  power-domains = < R8A7796_PD_ALWAYS_ON>;
> +  status = "disabled";
> +
> +  ports {
> +  #address-cells = <1>;
> +  #size-cells = <0>;
> +
> +  port@1 {
> +  #address-cells = <1>;
> +  #size-cells = <0>;
> +
> +  reg = <1>;
> +
> +  csi20vin0: endpoint@0 {
> +  reg = <0>;
> +  remote-endpoint = <>;
> +  };
> +  csi20vin1: endpoint@1 {
> +  reg = <1>;
> +  remote-endpoint = <>;
> +  };
> +  

[PATCH v7 1/2] media: rcar-csi2: add Renesas R-Car MIPI CSI-2 receiver documentation

[Niklas Söderlund]

From: Niklas Söderlund 

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
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
of which link are used are controlled by the VIN devices. There are only
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
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 
---
 .../devicetree/bindings/media/rcar-csi2.txt| 116 +
 1 file changed, 116 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/rcar-csi2.txt

diff --git a/Documentation/devicetree/bindings/media/rcar-csi2.txt 
b/Documentation/devicetree/bindings/media/rcar-csi2.txt
new file mode 100644
index ..f6e2027ee92b171a
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/rcar-csi2.txt
@@ -0,0 +1,116 @@
+Renesas R-Car MIPI CSI-2
+
+
+The rcar-csi2 device provides MIPI CSI-2 capabilities for the Renesas R-Car
+family of devices. It is to be used in conjunction with the R-Car VIN module,
+which provides the video capture capabilities.
+
+ - compatible: Must be one or more of the following
+   - "renesas,r8a7795-csi2" for the R8A7795 device.
+   - "renesas,r8a7796-csi2" for the R8A7796 device.
+   - "renesas,rcar-gen3-csi2" for a generic R-Car Gen3 compatible device.
+
+   When compatible with a generic version nodes must list the
+   SoC-specific version corresponding to the platform first
+   followed by the generic version.
+
+ - reg: the register base and size for the device registers
+ - interrupts: the interrupt for the device
+ - clocks: Reference to the parent clock
+
+The device node should contain two 'port' child nodes according to the
+bindings defined in Documentation/devicetree/bindings/media/
+video-interfaces.txt. Port 0 should connect the node that is the video
+source for to the CSI-2. Port 1 should connect all the R-Car VIN
+modules, which can make use of the CSI-2 module.
+
+- Port 0 - Video source
+   - Reg 0 - sub-node describing the endpoint that is the video source
+
+- Port 1 - VIN instances
+   - Reg 0 - sub-node describing the endpoint that is VIN0
+   - Reg 1 - sub-node describing the endpoint that is VIN1
+   - Reg 2 - sub-node describing the endpoint that is VIN2
+   - Reg 3 - sub-node describing the endpoint that is VIN3
+   - Reg 4 - sub-node describing the endpoint that is VIN4
+   - Reg 5 - sub-node describing the endpoint that is VIN5
+   - Reg 6 - sub-node describing the endpoint that is VIN6
+   - Reg 7 - sub-node describing the endpoint that is VIN7
+
+Example:
+
+/* SoC properties */
+
+csi20: csi2@fea8 {
+compatible = "renesas,r8a7796-csi2";
+reg = <0 0xfea8 0 0x1>;
+interrupts = <0 184 IRQ_TYPE_LEVEL_HIGH>;
+clocks = < CPG_MOD 714>;
+power-domains = < R8A7796_PD_ALWAYS_ON>;
+status = "disabled";
+
+ports {
+#address-cells = <1>;
+#size-cells = <0>;
+
+port@1 {
+#address-cells = <1>;
+#size-cells = <0>;
+
+reg = <1>;
+
+csi20vin0: endpoint@0 {
+reg = <0>;
+remote-endpoint = <>;
+};
+csi20vin1: endpoint@1 {
+reg = <1>;
+remote-endpoint = <>;
+};
+csi20vin2: endpoint@2 {
+reg = <2>;
+remote-endpoint = <>;
+};
+csi20vin3: endpoint@3 {
+reg = <3>;
+remote-endpoint = <>;
+};
+csi20vin4: endpoint@4 {
+reg =