Messages in this thread | | | Date | Fri, 22 Feb 2013 12:46:01 -0700 | From | Stephen Warren <> | Subject | Re: [RFC v2 1/3] power_supply: Define Binding for supplied-nodes |
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On 02/21/2013 04:11 PM, Rhyland Klein wrote: > This property is meant to be used in device nodes which represent > power_supply devices that wish to provide a list of supplies to > which they provide power. A common case is a AC Charger with > the batteries it powers.
> diff --git a/Documentation/devicetree/bindings/power_supply/power_supply.txt b/Documentation/devicetree/bindings/power_supply/power_supply.txt
> +Optional Properties: > + - power-supply : This property is added to a supply in order to list the > + devices which supply it power, referenced by their phandles.
DT properties that reference resources are usually named in the plural, so "power-supplies" would be more appropriate here.
It seems plausible that a single DT node could represent/instantiate multiple separate supply objects. I think we want to employ the standard pattern of <phandle args*> rather than just <phandle>.
That way, each supply that can supply others would have something like a #supply-cells = <n>, where n is the number of cells that the supply uses to name the multiple supplies provided by that node. 0 would be a common value here. 1 might be used for a node that represents many supplies.
When a client supply uses a providing supply as the supply(!), do you need any flags to parameterize the connection? If so, that might be cause for a supplier to have a larger #supply-cells, so the flags could be represented.
That all said, regulators assume 1 node == 1 regulator, so an alternative would be for a multi-supply node to include a child node per supply, e.g.:
power@xxx { ... supply1 { ... }; supply2 { ... }; };
client { supplies = <&supply1> <&supply2>; };
I don't recall why regulators went for the style above rather than the #supply-cells style. Cc Mark Brown for any comment here.
Also, do supplies and regulators need to inter-operate in any way (e.g. reference each-other in DT)?
> +Example: > + > + usb-charger: power@e { > + compatible = "some,usb-charger"; > + ... > + }; > + > + ac-charger: power@e { > + compatible = "some,ac-charger"; > + ... > + }; > + > + battery@b { > + compatible = "some,battery"; > + ... > + power-supply = <&usb-charger>, <&ac-charger>; > + };
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