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SubjectRe: [PATCH v5 1/6] dt-bindings: add bindings for USB physical connector
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On 09.03.2018 11:24, Roger Quadros wrote:
> 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@samsung.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.

I have proposed such property (and size also) in my first RFC [1]. Rod
did not like it :)

[1]: https://marc.info/?l=devicetree&m=150660411515233&w=2


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

I am aware of it, and property differentiating it was also in my earlier
iterations.
If there will be need to differentiate such connectors, adding property
max-speed or max-mode would do the thing.

>
>> +
>> +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.

It follows convention for other connectors: HDMI, DVI, ....

>
>> +- 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.

As you can see in discussion for previous iterations it follows
convention already established for other connectors.

>
> 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
Few lines above it is described: should be specified in case of USB-A,
USB-B non-fullsize connectors.

>
> 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

OK, I will fix both typos.

>
>> + 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.

Why?

Regards
Andrzej

>
>> +
>> + 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>;
>> + };
>> + };
>> + };
>> + };
>> +};
>>

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