Re: [PATCH 2/2] dt-bindings: extcon: Add support for cros-ec device

[Rob Herring]

On Mon, Feb 20, 2017 at 04:18:54PM +0100, Enric Balletbo i Serra wrote:
> From: Benson Leung <bleung@xxxxxxxxxxxx>
> 
> This patch add documentation for binding of USB Type C cable detection
> mechanism is using EXTCON subsystem. The device can detect the presence
> of display out but it may also detect other external accessories when
> external accessories is attached or detached.
> 
> Signed-off-by: Benson Leung <bleung@xxxxxxxxxxxx>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/extcon/extcon-cros-ec.txt  | 24 ++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/extcon/extcon-cros-ec.txt
> 
> diff --git a/Documentation/devicetree/bindings/extcon/extcon-cros-ec.txt b/Documentation/devicetree/bindings/extcon/extcon-cros-ec.txt
> new file mode 100644
> index 0000000..3576869
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/extcon/extcon-cros-ec.txt
> @@ -0,0 +1,24 @@
> +ChromeOS EC Type-C Extcon device

Extcon is a Linux term. Devicetree describes the h/w.

> +
> +On ChromeOS systems with USB Type C ports, the ChromeOS Embedded Controller is
> +able to detect the state of external accessories such as display adapters
> +or USB devices when said accessories are attached or detached.
> +
> +The node for this device must be under a cros-ec node like google,cros-ec-spi
> +or google,cros-ec-i2c.
> +
> +Required properties:
> +- compatible:		Should be "google,extcon-cros-ec".

Perhaps something indicating this is USB Type C related.

> +- google,usb-port-id:	Specifies the USB port ID to use.

What are the choices here? Most likely this should be some phandle back 
to the USB controller or hub.

> +
> +Example:
> +	cros-ec@0 {
> +		compatible = "google,cros-ec-i2c";
> +
> +		...
> +
> +		extcon {
> +			compatible = "google,extcon-cros-ec";
> +			google,usb-port-id = <0>;
> +		};
> +	}
> -- 
> 2.9.3
>