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

Rob Herring
2019-01-21T20:11:57Z

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 <ben.whitten@gmail.com>
> ---
> .../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 <afaerber@suse.de>
> + - Ben Whitten <ben.whitten@gmail.com>
> +
> +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/