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SubjectRe: [PATCH v2 1/4] dt-bindings: media: csi2dc: add bindings for microchip csi2dc
On Fri, Jul 03, 2020 at 10:44:13AM +0300, 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 <eugen.hristev@microchip.com>
> ---
> Changes in v2:
> - fixed warnings reported by dt_binding_check
>
>
> .../bindings/media/microchip,csi2dc.yaml | 185 ++++++++++++++++++
> 1 file changed, 185 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..b7c46f7ad2a4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/microchip,csi2dc.yaml
> @@ -0,0 +1,185 @@
> +# SPDX-License-Identifier: GPL-2.0-only

New bindings should be:

(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 <eugen.hristev@microchip.com>
> +
> +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.
> + It should contain one 'port' child node with one child 'endpoint' node.
> + This node should always have the 'reg' property as 0, being the first child
> + node.

This information should be expressed as a schema.

> + 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.
> + The reg property inside this 'port' node must have the 'reg' property as 1,
> + being the second child node.
> + This node must have one 'endpoint', and this 'endpoint' is related to the
> + virtual channel identifier.
> + The 'reg' property inside this 'endpoint' represents the CSI2 virtual channel
> + identifier.
> + This '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.

And all this.

> +
> + 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.

Better to be part of 'clocks'.

> +
> + 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:
> + description:
> + Physical base address and length of the registers set for the device.

That is every 'reg' prop. Drop.

> + maxItems: 1
> +
> + clocks:
> + maxItems: 2
> +
> + clock-names:
> + items:
> + - const: pclk
> + - const: scck
> +
> + microchip,clk-gated:
> + type: boolean
> + description:
> + If present, indicates that the clock is gated.
> + Otherwise, the clock is free-running.
> +
> + microchip,inter-line-delay:
> + allOf:
> + - $ref: /schemas/types.yaml#/definitions/uint32
> + - minimum: 1
> + - maximum: 16
> + default: 16
> + description:
> + Indicates how many clock cycles should be introduced between each line.
> +
> + port@0:
> + type: object
> + description:
> + Input port node, single endpoint describing the input pad.
> +
> + properties:
> + reg:
> + const: 0
> +
> + endpoint:
> + type: object
> +
> + properties:
> + remote-endpoint: true
> +
> + required:
> + - remote-endpoint
> +
> + additionalProperties: false
> +
> + additionalProperties: false
> +
> + port@1:
> + type: object
> + description:
> + Output port node, single endpoint, describing the output pad.
> +
> + properties:
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> + reg:
> + const: 1
> +
> + patternProperties:
> + "^endpoint@[0-9a-f]$":

Looks like only [0-3] is valid.

> + type: object
> +
> + properties:
> + reg:
> + enum: [0, 1, 2, 3]
> + description: virtual channel for the endpoint
> +
> + remote-endpoint: true
> +
> + required:
> + - remote-endpoint
> + - reg
> +
> + additionalProperties: false
> +
> + additionalProperties: false
> +
> +required:
> + - compatible
> + - reg
> + - clocks
> + - clock-names
> + - port@0
> +
> +examples:
> + - |
> + csi2dc@e1404000 {
> + compatible = "microchip,sama7g5-csi2dc";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0xe1404000 0x500>;
> + clocks = <&pclk>, <&scck>;
> + clock-names = "pclk", "scck";
> +
> + port@0 {
> + reg = <0>; /* must be 0, first child port */
> + csi2dc_in: endpoint { /* input from IDI interface */
> + remote-endpoint = <&csi2host_out>;
> + };
> + };
> +
> + port@1 {
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <1>; /* must be 1, second child port */
> + csi2dc_out: endpoint@2 {
> + reg = <2>; /* virtual channel identifier */
> + remote-endpoint = <&xisc_in>; /* output to sensor controller */
> + };
> + };
> + };
> +
> +...
> --
> 2.25.1
>

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