Message ID | 1361488272-21010-2-git-send-email-rklein@nvidia.com |
---|---|
State | Not Applicable, archived |
Headers | show |
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>; > + }; -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2/22/2013 2:46 PM, Stephen Warren wrote: > 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>; >> + }; The "connection" between supplier and supplies isn't really a hard connection. Essentially, the core code uses the names/nodes in the list and iterates over all the power_supplies that are registered and does matching. I don't have any experience working with a single node that would spawn multiple supplies, though the situation I am sure is possible. I am interested to see what the consensus is around this design for multiple supplies, as I don't have a preference either way. -rhyland
diff --git a/Documentation/devicetree/bindings/power_supply/power_supply.txt b/Documentation/devicetree/bindings/power_supply/power_supply.txt new file mode 100644 index 0000000..7d8951c --- /dev/null +++ b/Documentation/devicetree/bindings/power_supply/power_supply.txt @@ -0,0 +1,23 @@ +Power Supply Core Support + +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. + +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>; + };
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. Signed-off-by: Rhyland Klein <rklein@nvidia.com> --- v2: - Changed property to "power-supply" which should be contained in the battery rather than the charger. Also updated example to match. .../bindings/power_supply/power_supply.txt | 23 ++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 Documentation/devicetree/bindings/power_supply/power_supply.txt