Re: [PATCH v3 7/9] dt-bindings: media: Add Allwinner A83T MIPI CSI-2 bindings documentation

[Paul Kocialkowski <paul.kocialkowski@bootlin.com>]

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Hi Sakari,

On Wed 16 Mar 22, 15:26, Sakari Ailus wrote:
> Hi Paul,
> 
> Thanks for the patch.

And thanks for the review!

> On Wed, Mar 02, 2022 at 11:07:37PM +0100, Paul Kocialkowski wrote:
> > This introduces YAML bindings documentation for the Allwinner A83T
> > MIPI CSI-2 controller.
> > 
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > ---
> >  .../media/allwinner,sun8i-a83t-mipi-csi2.yaml | 138 ++++++++++++++++++
> >  1 file changed, 138 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-mipi-csi2.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-mipi-csi2.yaml b/Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-mipi-csi2.yaml
> > new file mode 100644
> > index 000000000000..75121b402435
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/allwinner,sun8i-a83t-mipi-csi2.yaml
> > @@ -0,0 +1,138 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/allwinner,sun8i-a83t-mipi-csi2.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Allwinner A83T MIPI CSI-2 Device Tree Bindings
> > +
> > +maintainers:
> > +  - Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > +
> > +properties:
> > +  compatible:
> > +    const: allwinner,sun8i-a83t-mipi-csi2
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    items:
> > +      - description: Bus Clock
> > +      - description: Module Clock
> > +      - description: MIPI-specific Clock
> > +      - description: Misc CSI Clock
> > +
> > +  clock-names:
> > +    items:
> > +      - const: bus
> > +      - const: mod
> > +      - const: mipi
> > +      - const: misc
> > +
> > +  resets:
> > +    maxItems: 1
> > +
> > +  ports:
> > +    $ref: /schemas/graph.yaml#/properties/ports
> > +
> > +    properties:
> > +      port@0:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
> > +        description: Input port, connect to a MIPI CSI-2 sensor
> > +
> > +        properties:
> > +          reg:
> > +            const: 0
> > +
> > +          endpoint:
> > +            $ref: video-interfaces.yaml#
> > +            unevaluatedProperties: false
> > +
> > +            properties:
> > +              clock-lanes:
> > +                maxItems: 1
> 
> Does the hardware support lane reordering? If not, the property should be
> omitted here.

I'm not sure what this relates to. Is it about inverting the clock lane with
a data lane? I'm a bit confused about logical vs physical lane in the context
of MIPI CSI-2.

The controller has dedicated pins for the clock and data lanes and supports
filtering packets based on virtual channel or data type.

Are the clock-lanes and data-lanes only relevant for reordering?
IIRC they are also necessary to get the lanes count in the driver.

> I can also remove the three lines here while applying the patches.

I think this series will need another iteration anyway, so let's wait.

Paul

> > +
> > +              data-lanes:
> > +                minItems: 1
> > +                maxItems: 4
> > +
> > +            required:
> > +              - data-lanes
> > +
> > +        additionalProperties: false
> > +
> > +      port@1:
> > +        $ref: /schemas/graph.yaml#/$defs/port-base
> > +        description: Output port, connect to a CSI controller
> > +
> > +        properties:
> > +          reg:
> > +            const: 1
> > +
> > +          endpoint:
> > +            $ref: video-interfaces.yaml#
> > +            unevaluatedProperties: false
> > +
> > +        additionalProperties: false
> > +
> > +    required:
> > +      - port@0
> > +      - port@1
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - clocks
> > +  - clock-names
> > +  - resets
> > +  - ports
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +    #include <dt-bindings/clock/sun8i-a83t-ccu.h>
> > +    #include <dt-bindings/reset/sun8i-a83t-ccu.h>
> > +
> > +    mipi_csi2: csi@1cb1000 {
> > +        compatible = "allwinner,sun8i-a83t-mipi-csi2";
> > +        reg = <0x01cb1000 0x1000>;
> > +        interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
> > +        clocks = <&ccu CLK_BUS_CSI>,
> > +                 <&ccu CLK_CSI_SCLK>,
> > +                 <&ccu CLK_MIPI_CSI>,
> > +                 <&ccu CLK_CSI_MISC>;
> > +        clock-names = "bus", "mod", "mipi", "misc";
> > +        resets = <&ccu RST_BUS_CSI>;
> > +
> > +        ports {
> > +            #address-cells = <1>;
> > +            #size-cells = <0>;
> > +
> > +            mipi_csi2_in: port@0 {
> > +                reg = <0>;
> > +
> > +                mipi_csi2_in_ov8865: endpoint {
> > +                    data-lanes = <1 2 3 4>;
> > +
> > +                    remote-endpoint = <&ov8865_out_mipi_csi2>;
> > +                };
> > +            };
> > +
> > +            mipi_csi2_out: port@1 {
> > +                reg = <1>;
> > +
> > +                mipi_csi2_out_csi: endpoint {
> > +                    remote-endpoint = <&csi_in_mipi_csi2>;
> > +                };
> > +            };
> > +        };
> > +    };
> > +
> > +...
> 
> -- 
> Kind regards,
> 
> Sakari Ailus

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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