Subject: Re: [PATCH 01/23] dt-bindings: introduce silabs,wfx.yaml

From: Rob Herring <[email-masked]>
Date: Tue, 13 Oct 2020 11:49:35 -0500

On Mon, Oct 12, 2020 at 12:46:26PM +0200, Jerome Pouiller wrote:
> From: Jérôme Pouiller <[email-masked]>
> 
> Signed-off-by: Jérôme Pouiller <[email-masked]>
> ---
>  .../bindings/net/wireless/silabs,wfx.yaml     | 125 ++++++++++++++++++
>  1 file changed, 125 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/net/wireless/silabs,wfx.yaml
> 
> diff --git a/Documentation/devicetree/bindings/net/wireless/silabs,wfx.yaml b/Documentation/devicetree/bindings/net/wireless/silabs,wfx.yaml
> new file mode 100644
> index 000000000000..43b5630c0407
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/wireless/silabs,wfx.yaml
> @@ -0,0 +1,125 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (c) 2020, Silicon Laboratories, Inc.
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/net/wireless/silabs,wfx.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Silicon Labs WFxxx devicetree bindings
> +
> +maintainers:
> +  - Jérôme Pouiller <[email-masked]>
> +
> +description:
> +  The WFxxx chip series can be connected via SPI or via SDIO.

What does this chip do? WiFi or some other wireless?

> +
> +  For SDIO':'
> +
> +    The driver is able to detect a WFxxx chip on SDIO bus by matching its Vendor
> +    ID and Product ID. However, driver will only provide limited features in
> +    this case. Thus declaring WFxxx chip in device tree is recommended (and may
> +    become mandatory in the future).
> +
> +    In addition, it is recommended to declare a mmc-pwrseq on SDIO host above
> +    WFx. Without it, you may encounter issues with warm boot. The mmc-pwrseq
> +    should be compatible with mmc-pwrseq-simple. Please consult
> +    Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt for more
> +    information.
> +
> +  For SPI':'
> +
> +    In add of the properties below, please consult
> +    Documentation/devicetree/bindings/spi/spi-controller.yaml for optional SPI
> +    related properties.
> +
> +  Note that in add of the properties below, the WFx driver also supports
> +  `mac-address` and `local-mac-address` as described in
> +  Documentation/devicetree/bindings/net/ethernet.txt

Note what ethernet.txt contains... This should have a $ref to 
ethernet-controller.yaml to express the above.

You can add 'mac-address: true' if you want to be explicit about what 
properties are used.

> +
> +properties:
> +  compatible:
> +    const: silabs,wf200

blank line between each DT property.

> +  reg:
> +    description:
> +      When used on SDIO bus, <reg> must be set to 1. When used on SPI bus, it is
> +      the chip select address of the device as defined in the SPI devices
> +      bindings.
> +    maxItems: 1
> +  spi-max-frequency:
> +    description: (SPI only) Maximum SPI clocking speed of device in Hz.

No need to redefine a common property.

> +    maxItems: 1

Not an array. Just need:

spi-max-frequency: true

> +  interrupts:
> +    description: The interrupt line. Triggers IRQ_TYPE_LEVEL_HIGH and
> +      IRQ_TYPE_EDGE_RISING are both supported by the chip and the driver. When
> +      SPI is used, this property is required. When SDIO is used, the "in-band"
> +      interrupt provided by the SDIO bus is used unless an interrupt is defined
> +      in the Device Tree.
> +    maxItems: 1
> +  reset-gpios:
> +    description: (SPI only) Phandle of gpio that will be used to reset chip
> +      during probe. Without this property, you may encounter issues with warm
> +      boot. (For legacy purpose, the gpio in inverted when compatible ==
> +      "silabs,wfx-spi")
> +
> +      For SDIO, the reset gpio should declared using a mmc-pwrseq.
> +    maxItems: 1
> +  wakeup-gpios:
> +    description: Phandle of gpio that will be used to wake-up chip. Without this
> +      property, driver will disable most of power saving features.
> +    maxItems: 1
> +  config-file:
> +    description: Use an alternative file as PDS. Default is `wf200.pds`. Only
> +      necessary for development/debug purpose.

'firmware-name' is typically what we'd use here. Though if just for 
debug/dev, perhaps do a debugfs interface for this instead. As DT should 
come from the firmware/bootloader, requiring changing the DT for 
dev/debug is not the easiest workflow compared to doing something from 
userspace.

> +    maxItems: 1

Looks like a string, not an array.

> +
> +required:
> +  - compatible
> +  - reg

Will need additionalProperties or unevaluatedProperties depending on 
whether you list out properties from ethernet-controller.yaml or not.

Rob