Re: [PATCH v2 10/12] dt-bindings: connector: add properties for typec power delivery

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 26.02.2018 12:49, Li Jun wrote:
> In case of usb-c-connector with power delivery support, add bingdings
> supported by current typec driver, so user can pass all those properties
> via dt.
>
> Signed-off-by: Li Jun <jun.li@xxxxxxx>
> ---
> Changes for v2:
> - Added typec properties are based on general usb connector bindings[1]
>   proposed by Andrzej Hajda.
> - Use the standard unit suffixes as defined in property-units.txt.
>
> [1] https://patchwork.kernel.org/patch/10231447/
>
>  .../bindings/connector/usb-connector.txt           | 43 ++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/connector/usb-connector.txt b/Documentation/devicetree/bindings/connector/usb-connector.txt
> index e1463f1..242f6df 100644
> --- a/Documentation/devicetree/bindings/connector/usb-connector.txt
> +++ b/Documentation/devicetree/bindings/connector/usb-connector.txt
> @@ -15,6 +15,30 @@ Optional properties:
>  - type: size of the connector, should be specified in case of USB-A, USB-B
>    non-fullsize connectors: "mini", "micro".
>  
> +Required properties for usb-c-connector with power delivery support:
> +- port-type: should be one of "source", "sink" or "dual".
> +- default-role: preferred power role if port-type is "dual"(drp), should be
> +  "sink" or "source".

Since port carries data and power, it would be better to explicitly
mention it in names of properties which can be ambiguous.
Maybe instead of 'port-type' you can use 'power-role', for example.
Other thing is that default-role is required only in case of DRP, so
maybe better would be to squash it in power-role, for example:
    power-role: should be on of "source", "sink", "dual-source",
"dual-sink", in case of dual roles suffix determines preferred role.


> +- src-pdos: An array of u32 with each entry providing supported power
> +  source data object(PDO), the detailed bit definitions of PDO can be found
> +  in "Universal Serial Bus Power Delivery Specification" chapter 6.4.1.2
> +  Source_Capabilities Message, the order of each entry(PDO) should follow
> +  the PD spec chapter 6.4.1. Required for power source and power dual role.
> +- snk-pdos: An array of u32 with each entry providing supported power
> +  sink data object(PDO), the detailed bit definitions of PDO can be found in
> +  "Universal Serial Bus Power Delivery Specification" chapter 6.4.1.3 Sink
> +  Capabilities Message, the order of each entry(PDO) should follow the PD
> +  spec chapter 6.4.1. Required for power sink and power dual role.

We should avoid magic numbers, magic numbers are bad :)
If we really need to use PDOs here, I think we can re-use PDO_* macros
[1] - DTC should be able to parse it, maybe some lifting will be necessary.

[1]:
https://elixir.bootlin.com/linux/v4.16-rc3/source/include/linux/usb/pd.h#L161
> +- max-snk-microvolt: The max voltage the sink can support in micro volts,
> +  required for power sink and power dual role.
> +- max-snk-microamp: The max current the sink can support in micro amps,
> +  required for power sink and power dual role.
> +- max-snk-microwatt-hours: The max power the sink can support in micro
> +  Watt-hours, required for power sink and power dual role.
> +- op-snk-microwatt-hours: Sink required operating power in micro Watt-hours,
> +  if source offered power is less then it, Capability Mismatch is set,
> +  required for power sink and power dual role.

What is the relation between above properties and PDOs specified earlier?
Are you sure all these props are required?

And general remark regarding all above properties. For me, most of them
are specific not to the port but to devices responsible for power
management: chargers, pmics,....
In many cases these properties are redundant with devices capabilities.
On the other side I guess in many cases it may be convenient to put them
here, so I am not sure what is better :)

Regards
Andrzej

> +
>  Required nodes:
>  - any data bus to the connector should be modeled using the OF graph bindings
>    specified in bindings/graph.txt, unless the bus is between parent node and
> @@ -73,3 +97,22 @@ ccic: s2mm005@33 {
>  		};
>  	};
>  };
> +
> +3. USB-C connector attached to a typec port controller(ptn5110), which has
> +power delivery support and enables drp.
> +
> +typec: ptn5110@50 {
> +	...
> +	usb_con: connector {
> +		compatible = "usb-c-connector";
> +		label = "USB-C";
> +		port-type = "dual";
> +		default-role = "sink";
> +		src-pdos = <0x380190c8>;
> +		snk-pdos = <0x380190c8 0x3802d0c8>;
> +		max-snk-microvolt = <9000>;
> +		max-snk-microamp = <2000>;
> +		max-snk-microwatt-hours = <18000>;
> +		op-snk-microwatt-hours = <9000>;
> +	};
> +};


--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux