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3261227d13
While converting to the json-schema, let's also take the opportunity to
further specify/clarify some more details about the DT binding.
For example, let's define the label where to put the states nodes, set a
pattern for nodename of the state nodes and finally add an example.
Fixes: a3f048b542 ("dt: psci: Update DT bindings to support hierarchical PSCI states")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[robh: drop type refs from standard unit properties]
Signed-off-by: Rob Herring <robh@kernel.org>
113 lines
3.6 KiB
Plaintext
113 lines
3.6 KiB
Plaintext
* Generic PM domains
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System on chip designs are often divided into multiple PM domains that can be
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used for power gating of selected IP blocks for power saving by reduced leakage
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current.
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This device tree binding can be used to bind PM domain consumer devices with
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their PM domains provided by PM domain providers. A PM domain provider can be
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represented by any node in the device tree and can provide one or more PM
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domains. A consumer node can refer to the provider by a phandle and a set of
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phandle arguments (so called PM domain specifiers) of length specified by the
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#power-domain-cells property in the PM domain provider node.
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==PM domain providers==
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See power-domain.yaml.
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==PM domain consumers==
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Required properties:
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- power-domains : A list of PM domain specifiers, as defined by bindings of
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the power controller that is the PM domain provider.
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Optional properties:
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- power-domain-names : A list of power domain name strings sorted in the same
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order as the power-domains property. Consumers drivers will use
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power-domain-names to match power domains with power-domains
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specifiers.
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Example:
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leaky-device@12350000 {
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compatible = "foo,i-leak-current";
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reg = <0x12350000 0x1000>;
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power-domains = <&power 0>;
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power-domain-names = "io";
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};
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leaky-device@12351000 {
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compatible = "foo,i-leak-current";
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reg = <0x12351000 0x1000>;
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power-domains = <&power 0>, <&power 1> ;
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power-domain-names = "io", "clk";
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};
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The first example above defines a typical PM domain consumer device, which is
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located inside a PM domain with index 0 of a power controller represented by a
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node with the label "power".
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In the second example the consumer device are partitioned across two PM domains,
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the first with index 0 and the second with index 1, of a power controller that
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is represented by a node with the label "power".
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Optional properties:
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- required-opps: This contains phandle to an OPP node in another device's OPP
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table. It may contain an array of phandles, where each phandle points to an
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OPP of a different device. It should not contain multiple phandles to the OPP
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nodes in the same OPP table. This specifies the minimum required OPP of the
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device(s), whose OPP's phandle is present in this property, for the
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functioning of the current device at the current OPP (where this property is
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present).
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Example:
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- OPP table for domain provider that provides two domains.
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domain0_opp_table: opp-table0 {
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compatible = "operating-points-v2";
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domain0_opp_0: opp-1000000000 {
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opp-hz = /bits/ 64 <1000000000>;
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opp-microvolt = <975000 970000 985000>;
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};
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domain0_opp_1: opp-1100000000 {
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opp-hz = /bits/ 64 <1100000000>;
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opp-microvolt = <1000000 980000 1010000>;
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};
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};
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domain1_opp_table: opp-table1 {
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compatible = "operating-points-v2";
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domain1_opp_0: opp-1200000000 {
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opp-hz = /bits/ 64 <1200000000>;
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opp-microvolt = <975000 970000 985000>;
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};
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domain1_opp_1: opp-1300000000 {
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opp-hz = /bits/ 64 <1300000000>;
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opp-microvolt = <1000000 980000 1010000>;
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};
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};
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power: power-controller@12340000 {
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compatible = "foo,power-controller";
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reg = <0x12340000 0x1000>;
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#power-domain-cells = <1>;
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operating-points-v2 = <&domain0_opp_table>, <&domain1_opp_table>;
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};
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leaky-device0@12350000 {
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compatible = "foo,i-leak-current";
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reg = <0x12350000 0x1000>;
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power-domains = <&power 0>;
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required-opps = <&domain0_opp_0>;
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};
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leaky-device1@12350000 {
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compatible = "foo,i-leak-current";
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reg = <0x12350000 0x1000>;
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power-domains = <&power 1>;
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required-opps = <&domain1_opp_1>;
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};
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[1]. Documentation/devicetree/bindings/power/domain-idle-state.yaml
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