[v5,1/3] dt-bindings: media: atmel: csi2dc: add bindings for microchip csi2dc

Commit Message

Eugen Hristev Nov. 12, 2020, 1:34 p.m. UTC

Add bindings documentation for Microchip CSI2 Demultiplexer controller.

CSI2DC is a demultiplexer from Synopsys IDI interface specification to
parallel interface connection or direct memory access.

Signed-off-by: Eugen Hristev <[e-mail]>
---
Changes in v5:
- modified bindings as per Rob Herring review

Changes in v4:
- Removed property for inter-line-delay and for clock continuous/non-continuous
- Removed virtual channel by reg for second endpoint

Changes in v3:
- Removed some text from description, as it was explained in the schema
- fixed other things as per Rob's review
- moved some text inside the schema, like the clock description

Changes in v2:
- fixed warnings reported by dt_binding_check

 .../bindings/media/microchip,csi2dc.yaml      | 119 ++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/microchip,csi2dc.yaml

Comments

Jacopo Mondi Nov. 16, 2020, 6:23 p.m. UTC | #1

Hello Eugen,

On Thu, Nov 12, 2020 at 03:34:35PM +0200, Eugen Hristev wrote:
> Add bindings documentation for Microchip CSI2 Demultiplexer controller.
>
> CSI2DC is a demultiplexer from Synopsys IDI interface specification to
> parallel interface connection or direct memory access.
>
> Signed-off-by: Eugen Hristev <[e-mail]>
> ---
> Changes in v5:
> - modified bindings as per Rob Herring review
>
> Changes in v4:
> - Removed property for inter-line-delay and for clock continuous/non-continuous
> - Removed virtual channel by reg for second endpoint
>
> Changes in v3:
> - Removed some text from description, as it was explained in the schema
> - fixed other things as per Rob's review
> - moved some text inside the schema, like the clock description
>
> Changes in v2:
> - fixed warnings reported by dt_binding_check
>
>  .../bindings/media/microchip,csi2dc.yaml      | 119 ++++++++++++++++++
>  1 file changed, 119 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
>
> diff --git a/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> new file mode 100644
> index 000000000000..e79f0d6ba9db
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> @@ -0,0 +1,119 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip CSI2 Demux Controller (CSI2DC)
> +
> +maintainers:
> +  - Eugen Hristev <[e-mail]>
> +
> +description:
> +  CSI2DC - Camera Serial Interface 2 Demux Controller
> +
> +  CSI2DC is a hardware block that receives incoming data from an IDI interface
> +  and filters packets based on their data type and virtual channel identifier,
> +  then converts the byte stream into a cross clock domain to a pixel stream
> +  to a parallel interface that can be read by a sensor controller.
> +
> +  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
> +  is connected to a sensor controller and the data pipe is accessible
> +  as a DMA slave port to a DMA controller.
> +
> +  CSI2DC supports a single 'port' node as a source pad with Synopsys 32-bit
> +  IDI interface. The connected endpoint must be a IDI interface compatible
> +  device (like Synopsys CSI2HOST) , that can provide 32-bit IDI interface
> +  connection as sink pad.

Comments on a description from a non-native speaker might be
mis-leading, take the following as suggestions only :)

the here mentioned port node is said to be a 'source' to which an IDI
interface that provides data is connected ? Is this a s/sink/source
mistake or did you mean the first port node has to be connected to a
source (the IDI interface) ?

Also, maybe it's me but 'pad' is a media-controller concept, which
should not be mentioned in bindings (as well as 'source' and 'sink'
but they have a more generic usage)

The first port, to me, is simply an 'IDI input port'

> +  For media entity and endpoints please refer to the bindings defined in
> +  Documentation/devicetree/bindings/media/video-interfaces.txt.

I would drop 'media-entity'. To be honest I would drop this phrase and
mention ../video-interfaces.txt in the ports description. Up to you.

> +  For Synopsys IDI interface please refer to
> +  Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
> +
> +  CSI2DC supports one 'port' node as sink pad with parallel interface. This is
> +  called video pipe.

I'm confused again, isn't the parallel interface an output ? Why is it
said to be a 'sink pad' ?

Isn't port one simply a 'video output port' ?

Also the association between bindings' 'port' and their representation
as media-controller constructs should in my opinion be avoided.
Bindings are about describing hardware, and they could be used by
non-Linux systems as well (at least, I've been told this multiple
times :)

> +  This port has an 'endpoint' can then be used as a source pad for another
> +  controller (next in pipeline).
> +  Please refer to the bindings defined in
> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
> +
> +  CSI2DC also supports direct access to the data through AHB, via DMA channel,
> +  called data pipe.

Is my understanding correct of this 'direct access' is not represented
in DTS ?

> +  Because of this, the sink 'port' child node (second) is not mandatory.
> +  If the sink 'port' child node is missing, only data pipe is available.

And so the DMA channel and the output video port are mutually
exclusive ? I feel like the DMA port should be described or at least
represented and made exclusive with port1 presence ?

> +
> +properties:
> +  compatible:
> +    const: microchip,sama7g5-csi2dc
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 2
> +
> +  clock-names:
> +    description:
> +      CSI2DC must have two clocks to function correctly. One clock is the
> +      peripheral clock for the inside functionality of the hardware block.
> +      This is named 'pclk'. The second clock must be the cross domain clock,
> +      in which CSI2DC will perform clock crossing. This clock must be fed
> +      by the next controller in pipeline, which usually is a sensor controller.
> +      Normally this clock should be given by this sensor controller who
> +      is also a clock source. This clock is named 'scck', sensor controller clock.
> +    items:
> +      - const: pclk
> +      - const: scck
> +
> +  ports:
> +    type: object
> +    description:
> +      List of ports
> +
> +    properties:
> +      port@0:
> +        type: object
> +        description:
> +          Input port node, single endpoint describing the input pad.
> +      port@1:
> +        type: object
> +        description:
> +          Output port node, single endpoint, describing the output pad.

That's a parallel video output, correct ? Does this port support any
configurable property of the ones defined by video-interfaces.txt ?

Thanks
   j
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - ports
> +
> +examples:
> +  - |
> +    csi2dc@e1404000 {
> +        compatible = "microchip,sama7g5-csi2dc";
> +        reg = <0xe1404000 0x500>;
> +        clocks = <&pclk>, <&scck>;
> +        clock-names = "pclk", "scck";
> +
> +        ports {
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +               port@0 {
> +                       reg = <0>; /* must be 0, first child port */
> +                       csi2dc_in: endpoint { /* input from IDI interface */
> +                               remote-endpoint = <&csi2host_out>;
> +                       };
> +               };
> +
> +               port@1 {
> +                       reg = <1>; /* must be 1, second child port */
> +                       csi2dc_out: endpoint {
> +                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
> +                       };
> +               };
> +        };
> +    };
> +
> +...
> --
> 2.25.1
>

Jacopo Mondi Nov. 17, 2020, 10:37 a.m. UTC | #2

Hi again,

On Thu, Nov 12, 2020 at 03:34:35PM +0200, Eugen Hristev wrote:
> Add bindings documentation for Microchip CSI2 Demultiplexer controller.
>
> CSI2DC is a demultiplexer from Synopsys IDI interface specification to
> parallel interface connection or direct memory access.
>
> Signed-off-by: Eugen Hristev <[e-mail]>
> ---
> Changes in v5:
> - modified bindings as per Rob Herring review
>
> Changes in v4:
> - Removed property for inter-line-delay and for clock continuous/non-continuous
> - Removed virtual channel by reg for second endpoint
>
> Changes in v3:
> - Removed some text from description, as it was explained in the schema
> - fixed other things as per Rob's review
> - moved some text inside the schema, like the clock description
>
> Changes in v2:
> - fixed warnings reported by dt_binding_check
>
>  .../bindings/media/microchip,csi2dc.yaml      | 119 ++++++++++++++++++
>  1 file changed, 119 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
>
> diff --git a/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> new file mode 100644
> index 000000000000..e79f0d6ba9db
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> @@ -0,0 +1,119 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip CSI2 Demux Controller (CSI2DC)
> +
> +maintainers:
> +  - Eugen Hristev <[e-mail]>
> +
> +description:
> +  CSI2DC - Camera Serial Interface 2 Demux Controller
> +
> +  CSI2DC is a hardware block that receives incoming data from an IDI interface
> +  and filters packets based on their data type and virtual channel identifier,
> +  then converts the byte stream into a cross clock domain to a pixel stream
> +  to a parallel interface that can be read by a sensor controller.
> +
> +  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
> +  is connected to a sensor controller and the data pipe is accessible
> +  as a DMA slave port to a DMA controller.
> +
> +  CSI2DC supports a single 'port' node as a source pad with Synopsys 32-bit
> +  IDI interface. The connected endpoint must be a IDI interface compatible
> +  device (like Synopsys CSI2HOST) , that can provide 32-bit IDI interface
> +  connection as sink pad.
> +  For media entity and endpoints please refer to the bindings defined in
> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
> +  For Synopsys IDI interface please refer to
> +  Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt

Is it me or this file doesn't exists on the most recent media/master
and on v5.10-rc4 ?

> +
> +  CSI2DC supports one 'port' node as sink pad with parallel interface. This is
> +  called video pipe.
> +  This port has an 'endpoint' can then be used as a source pad for another
> +  controller (next in pipeline).
> +  Please refer to the bindings defined in
> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
> +
> +  CSI2DC also supports direct access to the data through AHB, via DMA channel,
> +  called data pipe.
> +  Because of this, the sink 'port' child node (second) is not mandatory.
> +  If the sink 'port' child node is missing, only data pipe is available.
> +
> +properties:
> +  compatible:
> +    const: microchip,sama7g5-csi2dc
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 2
> +
> +  clock-names:
> +    description:
> +      CSI2DC must have two clocks to function correctly. One clock is the
> +      peripheral clock for the inside functionality of the hardware block.
> +      This is named 'pclk'. The second clock must be the cross domain clock,
> +      in which CSI2DC will perform clock crossing. This clock must be fed
> +      by the next controller in pipeline, which usually is a sensor controller.
> +      Normally this clock should be given by this sensor controller who
> +      is also a clock source. This clock is named 'scck', sensor controller clock.
> +    items:
> +      - const: pclk
> +      - const: scck
> +
> +  ports:
> +    type: object
> +    description:
> +      List of ports
> +
> +    properties:
> +      port@0:
> +        type: object
> +        description:
> +          Input port node, single endpoint describing the input pad.
> +      port@1:
> +        type: object
> +        description:
> +          Output port node, single endpoint, describing the output pad.
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - ports
> +
> +examples:
> +  - |
> +    csi2dc@e1404000 {
> +        compatible = "microchip,sama7g5-csi2dc";
> +        reg = <0xe1404000 0x500>;
> +        clocks = <&pclk>, <&scck>;
> +        clock-names = "pclk", "scck";
> +
> +        ports {
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +               port@0 {
> +                       reg = <0>; /* must be 0, first child port */
> +                       csi2dc_in: endpoint { /* input from IDI interface */
> +                               remote-endpoint = <&csi2host_out>;
> +                       };
> +               };
> +
> +               port@1 {
> +                       reg = <1>; /* must be 1, second child port */
> +                       csi2dc_out: endpoint {
> +                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
> +                       };
> +               };
> +        };
> +    };
> +
> +...
> --
> 2.25.1
>

Eugen Hristev Nov. 17, 2020, 11:14 a.m. UTC | #3

On 17.11.2020 12:37, Jacopo Mondi wrote:
> Hi again,
> 
> On Thu, Nov 12, 2020 at 03:34:35PM +0200, Eugen Hristev wrote:
>> Add bindings documentation for Microchip CSI2 Demultiplexer controller.
>>
>> CSI2DC is a demultiplexer from Synopsys IDI interface specification to
>> parallel interface connection or direct memory access.
>>
>> Signed-off-by: Eugen Hristev <[e-mail]>
>> ---
>> Changes in v5:
>> - modified bindings as per Rob Herring review
>>
>> Changes in v4:
>> - Removed property for inter-line-delay and for clock continuous/non-continuous
>> - Removed virtual channel by reg for second endpoint
>>
>> Changes in v3:
>> - Removed some text from description, as it was explained in the schema
>> - fixed other things as per Rob's review
>> - moved some text inside the schema, like the clock description
>>
>> Changes in v2:
>> - fixed warnings reported by dt_binding_check
>>
>>   .../bindings/media/microchip,csi2dc.yaml      | 119 ++++++++++++++++++
>>   1 file changed, 119 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
>> new file mode 100644
>> index 000000000000..e79f0d6ba9db
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
>> @@ -0,0 +1,119 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Microchip CSI2 Demux Controller (CSI2DC)
>> +
>> +maintainers:
>> +  - Eugen Hristev <[e-mail]>
>> +
>> +description:
>> +  CSI2DC - Camera Serial Interface 2 Demux Controller
>> +
>> +  CSI2DC is a hardware block that receives incoming data from an IDI interface
>> +  and filters packets based on their data type and virtual channel identifier,
>> +  then converts the byte stream into a cross clock domain to a pixel stream
>> +  to a parallel interface that can be read by a sensor controller.
>> +
>> +  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
>> +  is connected to a sensor controller and the data pipe is accessible
>> +  as a DMA slave port to a DMA controller.
>> +
>> +  CSI2DC supports a single 'port' node as a source pad with Synopsys 32-bit
>> +  IDI interface. The connected endpoint must be a IDI interface compatible
>> +  device (like Synopsys CSI2HOST) , that can provide 32-bit IDI interface
>> +  connection as sink pad.
>> +  For media entity and endpoints please refer to the bindings defined in
>> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
>> +  For Synopsys IDI interface please refer to
>> +  Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
> 
> Is it me or this file doesn't exists on the most recent media/master
> and on v5.10-rc4 ?

Hi Jacopo,

Thanks for reviewing this patch.
You are right. As I said at some point during the review, actually this 
controller has an input the IDI interface which is not currently in 
kernel. There is a patch series that adds the Synopsys platform driver, 
but nobody worked on it anymore and I use it for testing my driver.
You can see the last version that was sent here:

https://patchwork.linuxtv.org/project/linux-media/patch/[e-mail]/ 


I sent this series to understand how to improve and how to get my driver 
in kernel, but indeed there are holes, especially this input type of bus 
which is not in the subsystem either.

So how would you suggest to move forward ? Remove the reference to the 
synopsys binding and just leave 'IDI interface' which is undocumented ?

Eugen

> 
>> +
>> +  CSI2DC supports one 'port' node as sink pad with parallel interface. This is
>> +  called video pipe.
>> +  This port has an 'endpoint' can then be used as a source pad for another
>> +  controller (next in pipeline).
>> +  Please refer to the bindings defined in
>> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
>> +
>> +  CSI2DC also supports direct access to the data through AHB, via DMA channel,
>> +  called data pipe.
>> +  Because of this, the sink 'port' child node (second) is not mandatory.
>> +  If the sink 'port' child node is missing, only data pipe is available.
>> +
>> +properties:
>> +  compatible:
>> +    const: microchip,sama7g5-csi2dc
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 2
>> +
>> +  clock-names:
>> +    description:
>> +      CSI2DC must have two clocks to function correctly. One clock is the
>> +      peripheral clock for the inside functionality of the hardware block.
>> +      This is named 'pclk'. The second clock must be the cross domain clock,
>> +      in which CSI2DC will perform clock crossing. This clock must be fed
>> +      by the next controller in pipeline, which usually is a sensor controller.
>> +      Normally this clock should be given by this sensor controller who
>> +      is also a clock source. This clock is named 'scck', sensor controller clock.
>> +    items:
>> +      - const: pclk
>> +      - const: scck
>> +
>> +  ports:
>> +    type: object
>> +    description:
>> +      List of ports
>> +
>> +    properties:
>> +      port@0:
>> +        type: object
>> +        description:
>> +          Input port node, single endpoint describing the input pad.
>> +      port@1:
>> +        type: object
>> +        description:
>> +          Output port node, single endpoint, describing the output pad.
>> +
>> +additionalProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - clock-names
>> +  - ports
>> +
>> +examples:
>> +  - |
>> +    csi2dc@e1404000 {
>> +        compatible = "microchip,sama7g5-csi2dc";
>> +        reg = <0xe1404000 0x500>;
>> +        clocks = <&pclk>, <&scck>;
>> +        clock-names = "pclk", "scck";
>> +
>> +        ports {
>> +               #address-cells = <1>;
>> +               #size-cells = <0>;
>> +               port@0 {
>> +                       reg = <0>; /* must be 0, first child port */
>> +                       csi2dc_in: endpoint { /* input from IDI interface */
>> +                               remote-endpoint = <&csi2host_out>;
>> +                       };
>> +               };
>> +
>> +               port@1 {
>> +                       reg = <1>; /* must be 1, second child port */
>> +                       csi2dc_out: endpoint {
>> +                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
>> +                       };
>> +               };
>> +        };
>> +    };
>> +
>> +...
>> --
>> 2.25.1
>>

Jacopo Mondi Nov. 17, 2020, 12:08 p.m. UTC | #4

Hi Eugen,

On Tue, Nov 17, 2020 at 11:14:18AM +0000, [e-mail] wrote:
> On 17.11.2020 12:37, Jacopo Mondi wrote:
> > Hi again,
> >
> > On Thu, Nov 12, 2020 at 03:34:35PM +0200, Eugen Hristev wrote:
> >> Add bindings documentation for Microchip CSI2 Demultiplexer controller.
> >>
> >> CSI2DC is a demultiplexer from Synopsys IDI interface specification to
> >> parallel interface connection or direct memory access.
> >>
> >> Signed-off-by: Eugen Hristev <[e-mail]>
> >> ---
> >> Changes in v5:
> >> - modified bindings as per Rob Herring review
> >>
> >> Changes in v4:
> >> - Removed property for inter-line-delay and for clock continuous/non-continuous
> >> - Removed virtual channel by reg for second endpoint
> >>
> >> Changes in v3:
> >> - Removed some text from description, as it was explained in the schema
> >> - fixed other things as per Rob's review
> >> - moved some text inside the schema, like the clock description
> >>
> >> Changes in v2:
> >> - fixed warnings reported by dt_binding_check
> >>
> >>   .../bindings/media/microchip,csi2dc.yaml      | 119 ++++++++++++++++++
> >>   1 file changed, 119 insertions(+)
> >>   create mode 100644 Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> >>
> >> diff --git a/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> >> new file mode 100644
> >> index 000000000000..e79f0d6ba9db
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> >> @@ -0,0 +1,119 @@
> >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> +%YAML 1.2
> >> +---
> >> +$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> +
> >> +title: Microchip CSI2 Demux Controller (CSI2DC)
> >> +
> >> +maintainers:
> >> +  - Eugen Hristev <[e-mail]>
> >> +
> >> +description:
> >> +  CSI2DC - Camera Serial Interface 2 Demux Controller
> >> +
> >> +  CSI2DC is a hardware block that receives incoming data from an IDI interface
> >> +  and filters packets based on their data type and virtual channel identifier,
> >> +  then converts the byte stream into a cross clock domain to a pixel stream
> >> +  to a parallel interface that can be read by a sensor controller.
> >> +
> >> +  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
> >> +  is connected to a sensor controller and the data pipe is accessible
> >> +  as a DMA slave port to a DMA controller.
> >> +
> >> +  CSI2DC supports a single 'port' node as a source pad with Synopsys 32-bit
> >> +  IDI interface. The connected endpoint must be a IDI interface compatible
> >> +  device (like Synopsys CSI2HOST) , that can provide 32-bit IDI interface
> >> +  connection as sink pad.
> >> +  For media entity and endpoints please refer to the bindings defined in
> >> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
> >> +  For Synopsys IDI interface please refer to
> >> +  Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
> >
> > Is it me or this file doesn't exists on the most recent media/master
> > and on v5.10-rc4 ?
>
> Hi Jacopo,
>
> Thanks for reviewing this patch.
> You are right. As I said at some point during the review, actually this
> controller has an input the IDI interface which is not currently in
> kernel. There is a patch series that adds the Synopsys platform driver,
> but nobody worked on it anymore and I use it for testing my driver.
> You can see the last version that was sent here:
>
> https://patchwork.linuxtv.org/project/linux-media/patch/[e-mail]/
>
>
> I sent this series to understand how to improve and how to get my driver
> in kernel, but indeed there are holes, especially this input type of bus
> which is not in the subsystem either.
>
> So how would you suggest to move forward ? Remove the reference to the
> synopsys binding and just leave 'IDI interface' which is undocumented ?

mmm, I see... I was hoping it was a simple CSI-2 tx :)

The Synopsys proposed bindings do not tell much as they don't describe
the csi2host output port. I would just mention "Synopsys IDI
compatible interface" without mentioning a file that cannot be
accessed :)

Thanks
   j

>
> Eugen
>
> >
> >> +
> >> +  CSI2DC supports one 'port' node as sink pad with parallel interface. This is
> >> +  called video pipe.
> >> +  This port has an 'endpoint' can then be used as a source pad for another
> >> +  controller (next in pipeline).
> >> +  Please refer to the bindings defined in
> >> +  Documentation/devicetree/bindings/media/video-interfaces.txt.
> >> +
> >> +  CSI2DC also supports direct access to the data through AHB, via DMA channel,
> >> +  called data pipe.
> >> +  Because of this, the sink 'port' child node (second) is not mandatory.
> >> +  If the sink 'port' child node is missing, only data pipe is available.
> >> +
> >> +properties:
> >> +  compatible:
> >> +    const: microchip,sama7g5-csi2dc
> >> +
> >> +  reg:
> >> +    maxItems: 1
> >> +
> >> +  clocks:
> >> +    maxItems: 2
> >> +
> >> +  clock-names:
> >> +    description:
> >> +      CSI2DC must have two clocks to function correctly. One clock is the
> >> +      peripheral clock for the inside functionality of the hardware block.
> >> +      This is named 'pclk'. The second clock must be the cross domain clock,
> >> +      in which CSI2DC will perform clock crossing. This clock must be fed
> >> +      by the next controller in pipeline, which usually is a sensor controller.
> >> +      Normally this clock should be given by this sensor controller who
> >> +      is also a clock source. This clock is named 'scck', sensor controller clock.
> >> +    items:
> >> +      - const: pclk
> >> +      - const: scck
> >> +
> >> +  ports:
> >> +    type: object
> >> +    description:
> >> +      List of ports
> >> +
> >> +    properties:
> >> +      port@0:
> >> +        type: object
> >> +        description:
> >> +          Input port node, single endpoint describing the input pad.
> >> +      port@1:
> >> +        type: object
> >> +        description:
> >> +          Output port node, single endpoint, describing the output pad.
> >> +
> >> +additionalProperties: false
> >> +
> >> +required:
> >> +  - compatible
> >> +  - reg
> >> +  - clocks
> >> +  - clock-names
> >> +  - ports
> >> +
> >> +examples:
> >> +  - |
> >> +    csi2dc@e1404000 {
> >> +        compatible = "microchip,sama7g5-csi2dc";
> >> +        reg = <0xe1404000 0x500>;
> >> +        clocks = <&pclk>, <&scck>;
> >> +        clock-names = "pclk", "scck";
> >> +
> >> +        ports {
> >> +               #address-cells = <1>;
> >> +               #size-cells = <0>;
> >> +               port@0 {
> >> +                       reg = <0>; /* must be 0, first child port */
> >> +                       csi2dc_in: endpoint { /* input from IDI interface */
> >> +                               remote-endpoint = <&csi2host_out>;
> >> +                       };
> >> +               };
> >> +
> >> +               port@1 {
> >> +                       reg = <1>; /* must be 1, second child port */
> >> +                       csi2dc_out: endpoint {
> >> +                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
> >> +                       };
> >> +               };
> >> +        };
> >> +    };
> >> +
> >> +...
> >> --
> >> 2.25.1
> >>
>

Patch

diff --git a/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
new file mode 100644
index 000000000000..e79f0d6ba9db
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
@@ -0,0 +1,119 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/microchip,csi2dc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip CSI2 Demux Controller (CSI2DC)
+
+maintainers:
+  - Eugen Hristev <[e-mail]>
+
+description:
+  CSI2DC - Camera Serial Interface 2 Demux Controller
+
+  CSI2DC is a hardware block that receives incoming data from an IDI interface
+  and filters packets based on their data type and virtual channel identifier,
+  then converts the byte stream into a cross clock domain to a pixel stream
+  to a parallel interface that can be read by a sensor controller.
+
+  CSI2DC provides two pipes, one video pipe and one data pipe. Video pipe
+  is connected to a sensor controller and the data pipe is accessible
+  as a DMA slave port to a DMA controller.
+
+  CSI2DC supports a single 'port' node as a source pad with Synopsys 32-bit
+  IDI interface. The connected endpoint must be a IDI interface compatible
+  device (like Synopsys CSI2HOST) , that can provide 32-bit IDI interface
+  connection as sink pad.
+  For media entity and endpoints please refer to the bindings defined in
+  Documentation/devicetree/bindings/media/video-interfaces.txt.
+  For Synopsys IDI interface please refer to
+  Documentation/devicetree/bindings/media/snps,dw-csi-plat.txt
+
+  CSI2DC supports one 'port' node as sink pad with parallel interface. This is
+  called video pipe.
+  This port has an 'endpoint' can then be used as a source pad for another
+  controller (next in pipeline).
+  Please refer to the bindings defined in
+  Documentation/devicetree/bindings/media/video-interfaces.txt.
+
+  CSI2DC also supports direct access to the data through AHB, via DMA channel,
+  called data pipe.
+  Because of this, the sink 'port' child node (second) is not mandatory.
+  If the sink 'port' child node is missing, only data pipe is available.
+
+properties:
+  compatible:
+    const: microchip,sama7g5-csi2dc
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 2
+
+  clock-names:
+    description:
+      CSI2DC must have two clocks to function correctly. One clock is the
+      peripheral clock for the inside functionality of the hardware block.
+      This is named 'pclk'. The second clock must be the cross domain clock,
+      in which CSI2DC will perform clock crossing. This clock must be fed
+      by the next controller in pipeline, which usually is a sensor controller.
+      Normally this clock should be given by this sensor controller who
+      is also a clock source. This clock is named 'scck', sensor controller clock.
+    items:
+      - const: pclk
+      - const: scck
+
+  ports:
+    type: object
+    description:
+      List of ports
+
+    properties:
+      port@0:
+        type: object
+        description:
+          Input port node, single endpoint describing the input pad.
+      port@1:
+        type: object
+        description:
+          Output port node, single endpoint, describing the output pad.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - ports
+
+examples:
+  - |
+    csi2dc@e1404000 {
+        compatible = "microchip,sama7g5-csi2dc";
+        reg = <0xe1404000 0x500>;
+        clocks = <&pclk>, <&scck>;
+        clock-names = "pclk", "scck";
+
+        ports {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               port@0 {
+                       reg = <0>; /* must be 0, first child port */
+                       csi2dc_in: endpoint { /* input from IDI interface */
+                               remote-endpoint = <&csi2host_out>;
+                       };
+               };
+
+               port@1 {
+                       reg = <1>; /* must be 1, second child port */
+                       csi2dc_out: endpoint {
+                               remote-endpoint = <&xisc_in>; /* output to sensor controller */
+                       };
+               };
+        };
+    };
+
+...