Re: [PATCH v10 1/2] dt-bindings: spi: Add schema for Cadence QSPI Controller driver

[Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Tue, Feb 18, 2020 at 8:29 PM Ramuthevar,Vadivel MuruganX
<vadivel.muruganx.ramuthevar-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> wrote:
>
> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

Cc the DT list if you want this reviewed.

>
> Add dt-bindings documentation for Cadence-QSPI controller to support
> spi based flash memories.
>
> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> ---
>  .../devicetree/bindings/spi/cdns,qspi-nor.yaml     | 147 +++++++++++++++++++++
>  1 file changed, 147 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
>
> diff --git a/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
> new file mode 100644
> index 000000000000..1a4d6e8d0d0b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
> @@ -0,0 +1,147 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/spi/cdns,qspi-nor.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Cadence QSPI Flash Controller support
> +
> +maintainers:
> +  - Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> +
> +allOf:
> +  - $ref: "spi-controller.yaml#"
> +
> +description: |
> +  Binding Documentation for Cadence QSPI controller,This controller is
> +  present in the Intel LGM, Altera SoCFPGA and TI SoCs and this driver
> +  has been tested On Intel's LGM SoC.
> +
> +  - compatible : should be one of the following:
> +        Generic default - "cdns,qspi-nor".
> +        For TI 66AK2G SoC - "ti,k2g-qspi", "cdns,qspi-nor".
> +        For TI AM654 SoC  - "ti,am654-ospi", "cdns,qspi-nor".
> +        For Intel LGM SoC - "intel,lgm-qspi", "cdns,qspi-nor".
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +        - enum:
> +           - ti,k2g-qspi
> +        - const: cdns,qspi-nor
> +
> +      - items:
> +        - enum:
> +           - ti,am654-ospi
> +        - const: cdns,qspi-nor
> +
> +      - items:
> +        - enum:
> +           - intel,lgm-qspi
> +        - const: cdns,qspi-nor
> +
> +      - items:
> +        - const: cdns,qspi-nor
> +
> +  reg:
> +    maxItems: 2
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  cdns,fifo-depth:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Size of the data FIFO in words.

A 4GB fifo is valid? Add some constraints.

> +
> +  cdns,fifo-width:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Bus width of the data FIFO in bytes.

Add some constraints.

> +
> +  cdns,trigger-address:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      32-bit indirect AHB trigger address.
> +
> +  cdns,rclk-en:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Flag to indicate that QSPI return clock is used to latch the read data
> +      rather than the QSPI clock. Make sure that QSPI return clock is populated
> +      on the board before using this property.
> +
> +# subnode's properties
> +patternProperties:
> +  "^.*@[0-9a-fA-F]+$":
> +    type: object
> +    description:
> +      flash device uses the subnodes below defined properties.
> +
> +  cdns,read-delay:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Delay for read capture logic, in clock cycles.

4 billion clock delay is valid?

> +
> +  cdns,tshsl-ns:
> +    $ref: /schemas/types.yaml#/definitions/uint32

You can drop this, anything with a standard unit suffix already has a type.

> +    description: |
> +      Delay in nanoseconds for the length that the master mode chip select
> +      outputs are de-asserted between transactions.

Constraints...?

> +
> +  cdns,tsd2d-ns:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Delay in nanoseconds between one chip select being de-activated
> +      and the activation of another.
> +
> +  cdns,tchsh-ns:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Delay in nanoseconds between last bit of current transaction and
> +      deasserting the device chip select (qspi_n_ss_out).
> +
> +  cdns,tslch-ns:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Delay in nanoseconds between setting qspi_n_ss_out low and
> +      first bit transfer.
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - cdns,fifo-depth
> +  - cdns,fifo-width
> +  - cdns,trigger-address
> +
> +examples:
> +  - |
> +    qspi: spi@ff705000 {
> +          compatible = "cdns,qspi-nor";
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +          reg = <0xff705000 0x1000>,
> +                <0xffa00000 0x1000>;
> +          interrupts = <0 151 4>;
> +          clocks = <&qspi_clk>;
> +          cdns,fifo-depth = <128>;
> +          cdns,fifo-width = <4>;
> +          cdns,trigger-address = <0x00000000>;
> +
> +          flash0: n25q00@0 {
> +              compatible = "jedec,spi-nor";
> +              reg = <0x0>;
> +              cdns,read-delay = <4>;
> +              cdns,tshsl-ns = <50>;
> +              cdns,tsd2d-ns = <50>;
> +              cdns,tchsh-ns = <4>;
> +              cdns,tslch-ns = <4>;
> +          };
> +    };
> +
> --
> 2.11.0
>