Re: [PATCH 2/3] dt-bindings: fpga: Add Efinix serial SPI programming bindings

[Krzysztof Kozlowski <krzk@kernel.org>]

On 27/09/2024 16:14, iansdannapel@gmail.com wrote:
> From: Ian Dannapel <iansdannapel@gmail.com>
> 
> Add device tree binding documentation for configuring Efinix FPGA
> using serial SPI passive programming mode.
> 
> Signed-off-by: Ian Dannapel <iansdannapel@gmail.com>
> ---
>  .../fpga/efinix,trion-spi-passive.yaml        | 85 +++++++++++++++++++
>  1 file changed, 85 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/fpga/efinix,trion-spi-passive.yaml
> 
> diff --git a/Documentation/devicetree/bindings/fpga/efinix,trion-spi-passive.yaml b/Documentation/devicetree/bindings/fpga/efinix,trion-spi-passive.yaml
> new file mode 100644
> index 000000000000..ec6697fa6f44
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/efinix,trion-spi-passive.yaml
> @@ -0,0 +1,85 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/fpga/efinix,trion-spi-passive.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Efinix SPI FPGA Manager
> +
> +maintainers:
> +  - Ian Dannapel <iansdannapel@gmail.com>
> +
> +description: |
> +  Efinix Trion and Titanium Series FPGAs support a method of loading the
> +  bitstream over what is referred to as "SPI Passive Programming".
> +  Only serial (1x bus width) is supported, setting the programming mode
> +  is not in the scope the this manager and must be done elsewhere.
> +
> +  Warning: The slave serial link is not technically SPI and therefore it is
> +  not recommended to have other devices on the same bus since it might
> +  interfere or be interfered by other transmissions.
> +
> +  References:
> +  - https://www.efinixinc.com/docs/an033-configuring-titanium-fpgas-v2.6.pdf
> +  - https://www.efinixinc.com/docs/an006-configuring-trion-fpgas-v6.0.pdf
> +
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - efinix,trion-spi-passive
> +      - efinix,titanium-spi-passive

1. Your driver suggests these are compatible, so make them compatible
with using fallback.

2. What is "spi-passive"? Compatible is supposed to be the name of the
device, so I assume this is "trion"? Can trion be anything else than fpga?

> +
> +  spi-cpha: true
> +
> +  spi-cpol: true
> +
> +  spi-max-frequency:
> +    maximum: 25000000
> +
> +  reg:
> +    maxItems: 1
> +
> +  creset-gpios:

reset-gpios

Do not invent own properties.

> +    description:
> +      reset and re-configuration trigger pin (low active)
> +    maxItems: 1
> +
> +  cs-gpios:
> +    description:
> +      chip-select pin (low active)

Eee? That's a property of controller, not child. Aren't you duplicating
existing controller property?

> +    maxItems: 1
> +
> +  cdone-gpios:
> +    description:
> +      optional configuration done status pin (high active)
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - creset-gpios
> +  - cs-gpios
> +
> +additionalProperties: false

unevaluatedProperties instead

> +



Best regards,
Krzysztof