Subject: Re: [PATCH lora-next 1/4] dt-bindings: lora: sx130x: add basic documentation

From: Rob Herring <[email-masked]>
Date: Mon, 21 Jan 2019 14:11:52 -0600

On Tue, Jan 08, 2019 at 05:41:29PM +0900, Ben Whitten wrote:
> Add basic documentation in YAML format for the sx130x series concentrators
> from Semtech.
> Required is; the location on the SPI bus, the reset gpio and the node for
> downstream IQ radios, typically sx125x.
> 
> Signed-off-by: Ben Whitten <[email-masked]>
> ---
>  .../bindings/lora/semtech,sx130x.yaml         | 87 +++++++++++++++++++
>  1 file changed, 87 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/lora/semtech,sx130x.yaml
> 
> diff --git a/Documentation/devicetree/bindings/lora/semtech,sx130x.yaml b/Documentation/devicetree/bindings/lora/semtech,sx130x.yaml
> new file mode 100644
> index 000000000000..ad263bc4e60d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/lora/semtech,sx130x.yaml
> @@ -0,0 +1,87 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/lora/semtech,sx130x.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Semtech LoRa concentrator
> +
> +maintainers:
> +  - Andreas Färber <[email-masked]>
> +  - Ben Whitten <[email-masked]>
> +
> +description: |
> +  Semtech LoRa concentrator sx130x digital baseband chip is capable of
> +  demodulating LoRa signals on 8 channels simultaneously.
> +
> +  It is typically paired with two sx125x IQ radios controlled over an
> +  SPI directly from the concentrator.
> +
> +  The concentrator itself it controlled over SPI.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +        - semtech,sx1301
> +        - semtech,sx1308
> +
> +  reg:
> +    maxItems: 1
> +    description: The chip select on the SPI bus.
> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: A connection of the reset gpio line.
> +
> +  spi-max-frequency:
> +    maximum: 10000000
> +    default: 8000000
> +    description: The frequency of the SPI communication to the concentrator,
> +      in Hz. Maximum SPI frequency is 10MHz although 8MHz is typically used
> +      on a number of cards.
> +
> +  radio-spi:
> +    description: The concentrator has two radios connected which are contained
> +      within the following node.
> +
> +    properties:
> +      '#address-cells':
> +        const: 1
> +
> +      '#size-cells':
> +        const: 0
> +
> +    required:
> +      - '#address-cells'
> +      - '#size-cells'
> +
> +required:
> +  - compatible
> +  - reg
> +  - reset-gpios
> +  - radio-spi
> +
> +examples:
> +  - |

One more comment. Make sure you "build" the schema with 
'dt_binding_check' target. That builds the examples.

It is also checked by a CI job and the status is added to patchwork[1]. 
(Though it didn't work correctly for this one and I just fixed it.)

> +    concentrator0: lora@0 {

This example doesn't build because there's an expectation of the top 
level nodes being MMIO if there's a reg prop. You just need to wrap this 
in a parent node representing a spi controller:

spi {
  #address-cells = <1>;
  #size-cells = <0>;

  ...

};

> +      compatible = "semtech,sx1301";
> +      reg = <0>;
> +      reset-gpios = <&pioB 27 GPIO_ACTIVE_HIGH>;
> +      spi-max-frequency = <8000000>;
> +
> +      radio-spi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        radio0: lora@0 {
> +          compatible = "semtech,sx1257";
> +          reg = <0>;
> +        };
> +
> +        radio1: lora@1 {
> +          compatible = "semtech,sx1257";
> +          reg = <1>;
> +        };
> +      };
> +    };

[1] https://patchwork.ozlabs.org/patch/1021773/