Re: [PATCH v7 2/2] dt-bindings: fpga: document Lattice sysCONFIG FPGA manager

[Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>]

On 24/08/2022 18:01, Ivan Bornyakov wrote:
> Add Device Tree Binding doc for configuring Lattice ECP5 and MachXO2
> FPGAs over Slave SPI sysCONFIG interface.
> 
> Signed-off-by: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
> ---
>  .../bindings/fpga/lattice,sysconfig.yaml      | 103 ++++++++++++++++++
>  1 file changed, 103 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/fpga/lattice,sysconfig.yaml
> 
> diff --git a/Documentation/devicetree/bindings/fpga/lattice,sysconfig.yaml b/Documentation/devicetree/bindings/fpga/lattice,sysconfig.yaml
> new file mode 100644
> index 000000000000..596776427a00
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/lattice,sysconfig.yaml
> @@ -0,0 +1,103 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/fpga/lattice,sysconfig.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Lattice Slave SPI sysCONFIG FPGA manager
> +
> +maintainers:
> +  - Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx>
> +
> +description: |
> +  Lattice sysCONFIG port, which is used for FPGA configuration, among others,
> +  have Slave Serial Peripheral Interface. Only full reconfiguration is
> +  supported.
> +
> +  Programming of ECP5 is done by writing uncompressed bitstream image in .bit
> +  format into FPGA's SRAM configuration memory.
> +
> +  Programming of MachXO2 is done by writing configuration data into device's
> +  internal non-volatile Flash memory, then Self-Download of data from Flash
> +  into SRAM is issued.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - lattice,ecp5-fpga-mgr
> +      - lattice,machxo2-fpga-mgr
> +
> +  reg:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: lattice,machxo2-fpga-mgr
> +    then:
> +      properties:
> +        spi-max-frequency:
> +          maximum: 66000000
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: lattice,ecp5-fpga-mgr
> +    then:
> +      properties:
> +        spi-max-frequency:
> +          maximum: 60000000
> +        program-gpios:
> +          description:
> +            A GPIO line connected to PROGRAMN (active low) pin of the device.
> +            Initiates configuration sequence.
> +          maxItems: 1
> +        init-gpios:
> +          description:
> +            A GPIO line connected to INITN (active low) pin of the device.
> +            Indicates that the FPGA is ready to be configured.
> +          maxItems: 1
> +        done-gpios:
> +          description:
> +            A GPIO line connected to DONE (active high) pin of the device.
> +            Indicates that the configuration sequence is complete.
> +          maxItems: 1

Define instead the properties in top-level properties and disallow them
for other variant (program-gpios: false). Required can stay.

> +      required:
> +        - program-gpios
> +        - init-gpios
> +        - done-gpios
> +


Best regards,
Krzysztof