linux-kernel - Re: [PATCH next v10 03/11] dt-bindings: usb: add binding for USB GPIO based connection detection driver

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Date:   Tue, 27 Aug 2019 13:31:54 -0500
From:   Rob Herring <robh@...nel.org>
To:     Chunfeng Yun <chunfeng.yun@...iatek.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Biju Das <biju.das@...renesas.com>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        Li Jun <jun.li@....com>,
        Badhri Jagan Sridharan <badhri@...gle.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Min Guo <min.guo@...iatek.com>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Nagarjuna Kristam <nkristam@...dia.com>
Subject: Re: [PATCH next v10 03/11] dt-bindings: usb: add binding for USB
 GPIO based connection detection driver

On Fri, Aug 23, 2019 at 03:57:13PM +0800, Chunfeng Yun wrote:
> It's used to support dual role switch via GPIO when use Type-B
> receptacle, typically the USB ID pin is connected to an input
> GPIO, and also used to enable/disable device when the USB Vbus
> pin is connected to an input GPIO.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@...iatek.com>
> ---
> v9~v10 no changes
> 
> v8 changes:
>  1. rename the title
>  2. change the compatible as "linux,usb-conn-gpio" instead of
>     "linux,typeb-conn-gpio"

I don't think that is an improvement. How about 'gpio-usb-b-connector' 
to be consistent.

> 
> v7 changes:
>  1. add description for device only mode
> 
> v6 changes:
>  1. remove status and port nodes in example
>  2. make vbus-supply as optional property
> 
> v5 changes:
>  1. treat type-B connector as child device of USB controller's, but not
>     as a separate virtual device, suggested by Rob
>  2. put connector's port node under connector node, suggested by Rob
> 
> v4 no changes
> 
> v3 changes:
>  1. treat type-B connector as a virtual device, but not child device of
>     USB controller's
> 
> v2 changes:
>   1. new patch to make binding clear suggested by Hans
> ---
>  .../devicetree/bindings/usb/usb-conn-gpio.txt | 31 +++++++++++++++++++
>  1 file changed, 31 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/usb/usb-conn-gpio.txt
> 
> diff --git a/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt b/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt
> new file mode 100644
> index 000000000000..d4d107fedc22
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/usb-conn-gpio.txt
> @@ -0,0 +1,31 @@
> +USB GPIO Based Connection Detection
> +
> +This is typically used to switch dual role mode from the USB ID pin connected
> +to an input GPIO, and also used to enable/disable device mode from the USB
> +Vbus pin connected to an input GPIO.
> +
> +Required properties:
> +- compatible : should include "linux,usb-conn-gpio" and "usb-b-connector".
> +- id-gpios, vbus-gpios : input gpios, either one of them must be present,
> +	and both can be present as well.
> +	see connector/usb-connector.txt
> +
> +Optional properties:
> +- vbus-supply : can be present if needed when supports dual role mode.
> +	see connector/usb-connector.txt
> +
> +- Sub-nodes:
> +	- port : can be present.
> +		see graph.txt
> +
> +Example:
> +
> +&mtu3 {
> +	connector {
> +		compatible = "linux,usb-conn-gpio", "usb-b-connector";
> +		label = "micro-USB";

'label' is for a human identifying a particular connector when there are 
multiple (of the same type). So not a great example here.

> +		type = "micro";
> +		id-gpios = <&pio 12 GPIO_ACTIVE_HIGH>;
> +		vbus-supply = <&usb_p0_vbus>;
> +	};
> +};
> -- 
> 2.23.0
>