Date:   Fri, 9 Mar 2018 12:24:44 +0200
From:   Roger Quadros <rogerq@...com>
To:     Andrzej Hajda <a.hajda@...sung.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>
CC:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        <dri-devel@...ts.freedesktop.org>, Inki Dae <inki.dae@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Archit Taneja <architt@...eaurora.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-samsung-soc@...r.kernel.org>, <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v5 1/6] dt-bindings: add bindings for USB physical
 connector

Hi,

On 27/02/18 09:11, Andrzej Hajda wrote:
> These bindings allow to describe most known standard USB connectors
> and it should be possible to extend it if necessary.
> USB connectors, beside USB can be used to route other protocols,
> for example UART, Audio, MHL. In such case every device passing data
> through the connector should have appropriate graph bindings.
> 
> Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
> ---
> v4:
> - improved 'type' description (Rob),
> - improved description of 2nd example (Rob).
> v3:
> - removed MHL port (samsung connector will have separate bindings),
> - added 2nd example for USB-C,
> - improved formatting.
> v2:
> - moved connector type(A,B,C) to compatible string (Rob),
> - renamed size property to type (Rob),
> - changed type description to be less confusing (Laurent),
> - removed vendor specific compatibles (implied by graph port number),
> - added requirement of connector being a child of IC (Rob),
> - removed max-mode (subtly suggested by Rob, it should be detected anyway
>   by USB Controller in runtime, downside is that device is not able to
>   report its real capabilities, maybe better would be to make it optional(?)),
> - assigned port numbers to data buses (Rob).
> 
> Regards
> Andrzej
> ---
>  .../bindings/connector/usb-connector.txt           | 75 ++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/connector/usb-connector.txt
> 
> diff --git a/Documentation/devicetree/bindings/connector/usb-connector.txt b/Documentation/devicetree/bindings/connector/usb-connector.txt
> new file mode 100644
> index 000000000000..e1463f14af38
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/connector/usb-connector.txt
> @@ -0,0 +1,75 @@
> +USB Connector
> +=============
> +
> +USB connector node represents physical USB connector. It should be
> +a child of USB interface controller.
> +
> +Required properties:
> +- compatible: describes type of the connector, must be one of:
> +    "usb-a-connector",
> +    "usb-b-connector",
> +    "usb-c-connector".

compatible should be just "usb-connector"

Type should be a property

type: type of usb connector "A", "B", "AB", "C"
AB is for dual-role connectors.

micro super-speed and high-speed connectors are different. How do you differentiate that?

> +
> +Optional properties:
> +- label: symbolic name for the connector,

Why do you need label? We can't maintain consistency as people will put creative names there.
Device/bus driver could generate a valid label.

> +- type: size of the connector, should be specified in case of USB-A, USB-B
> +  non-fullsize connectors: "mini", "micro".

type is misleading. Type is usually A/B/C. It should be size here instead.

size: size of the connector if not standard size. "mini", "micro"

If not specified it is treated as standard sized connector.
e.g. for Type-C there is no mini/micro. so size doesn't have to be specificed

What about Type-C connector?
> +
> +Required nodes:
> +- any data bus to the connector should be modeled using the OF graph bindings

s/modeled/modelled

> +  specified in bindings/graph.txt, unless the bus is between parent node and
> +  the connector. Since single connector can have multpile data buses every bus

s/multpile/multiple

> +  has assigned OF graph port number as follows:
> +    0: High Speed (HS), present in all connectors,
> +    1: Super Speed (SS), present in SS capable connectors,
> +    2: Sideband use (SBU), present in USB-C.
> +
> +Examples
> +--------
> +
> +1. Micro-USB connector with HS lines routed via controller (MUIC):
> +
> +muic-max77843@66 {
> +	...
> +	usb_con: connector {
> +		compatible = "usb-b-connector";
> +		label = "micro-USB";
> +		type = "micro";
> +	};
> +};
> +
> +2. USB-C connector attached to CC controller (s2mm005), HS lines routed
> +to companion PMIC (max77865), SS lines to USB3 PHY and SBU to DisplayPort.
> +DisplayPort video lines are routed to the connector via SS mux in USB3 PHY.
> +
> +ccic: s2mm005@33 {
> +	...
> +	usb_con: connector {
> +		compatible = "usb-c-connector";
> +		label = "USB-C";

The label is not consistent with the earlier example.

> +
> +		ports {
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +
> +			port@0 {
> +				reg = <0>;
> +				usb_con_hs: endpoint {
> +					remote-endpoint = <&max77865_usbc_hs>;
> +				};
> +			};
> +			port@1 {
> +				reg = <1>;
> +				usb_con_ss: endpoint {
> +					remote-endpoint = <&usbdrd_phy_ss>;
> +				};
> +			};
> +			port@2 {
> +				reg = <2>;
> +				usb_con_sbu: endpoint {
> +					remote-endpoint = <&dp_aux>;
> +				};
> +			};
> +		};
> +	};
> +};
> 

-- 
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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