Re: [PATCH lora-next 2/4] dt-bindings: lora: sx125x: add basic documentation

Andreas Färber
2019-01-12T03:48:48Z

Am 08.01.19 um 09:41 schrieb Ben Whitten:
> The sx125x family are IQ radio transceivers from Semtech configured over
> SPI, they are typically connected to an sx130x series concentrator however
> may be connected to a host directly.

"SX125x" and "SX130x"

>
> Required properties include the radio number of the host or concentrator
> bus.
>
> Signed-off-by: Ben Whitten <ben.whitten@gmail.com>
> ---
> .../bindings/lora/semtech,sx125x.yaml | 45 +++++++++++++++++++
> 1 file changed, 45 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/lora/semtech,sx125x.yaml
>
> diff --git a/Documentation/devicetree/bindings/lora/semtech,sx125x.yaml b/Documentation/devicetree/bindings/lora/semtech,sx125x.yaml
> new file mode 100644
> index 000000000000..5eadec860b70
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/lora/semtech,sx125x.yaml
> @@ -0,0 +1,45 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/lora/semtech,sx125x.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Semtech IQ modulator/de-modulator transeiver
> +
> +maintainers:
> + - Andreas Färber <afaerber@suse.de>
> + - Ben Whitten <ben.whitten@gmail.com>
> +
> +description: |
> + The sx125x family are highly integrated RF front-end to digital I and Q
> + modulator/demodulator Multi-PHY mode transceiver capable of supporting
> + multiple constant and non-constant envelope modulation schemes.

"SX125x"

"are ... transceivers"

> +
> +properties:
> + compatible:
> + items:
> + - enum:
> + - semtech,sx1255
> + - semtech,sx1257
> + - semtech,sx1258

Do we need all three? Probably yes for the concentrator to make decisions?

> +
> + reg:
> + maxItems: 1
> + description: The chip select on the SPI bus or radio number in concentrator.

", with radio A = 0 and radio B = 1."

> +
> + spi-max-frequency:
> + maximum: 10000000
> + default: 8000000
> + description: The frequency of the SPI communication to the radio,
> + in Hz. Maximum SPI frequency is 10MHz.

If on the concentrator's SPI bus then this is unused. You don't mark it
required below, so maybe add a textual note?

> +
> +required:
> + - compatible
> + - reg
> +
> +examples:
> + - |
> + radio0: lora@0 {
> + compatible = "semtech,sx1257";
> + reg = <0>;
> + };

If you compare my sx127x implementation, should we prepare a
"radio-frequency" (or "radio-center-frequency") property for the
antenna, to preconfigure the driver during probe? Contents would then be
<868000000>, for example.

Thanks,
Andreas

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