Add binding documentation for the new power-domains-child-ids property,
which works in conjunction with the existing power-domains property to
establish parent-child relationships between a multi-domain power domain
provider and external parent domains.

Each element in the uint32 array identifies the child domain
ID (index) within the provider that should be made a child domain of
the corresponding phandle entry in power-domains. The two arrays must
have the same number of elements.

Signed-off-by: Kevin Hilman (TI) <khilman@baylibre.com>
---
 Documentation/devicetree/bindings/power/power-domain.yaml | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
index b1147dbf2e73..a3d2af124d37 100644
--- a/Documentation/devicetree/bindings/power/power-domain.yaml
+++ b/Documentation/devicetree/bindings/power/power-domain.yaml
@@ -68,6 +68,21 @@ properties:
       by the given provider should be subdomains of the domain specified
       by this binding.
 
+  power-domains-child-ids:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description:
+      An array of child domain IDs that correspond to the power-domains
+      property. This property is only applicable to power domain providers
+      with "#power-domain-cells" > 0 (i.e., providers that supply multiple
+      power domains). It specifies which of the provider's child domains
+      should be associated with each parent domain listed in the power-domains
+      property. The number of elements in this array must match the number of
+      phandles in the power-domains property. Each element specifies the child
+      domain ID (index) that should be made a child domain of the corresponding
+      parent domain. This enables hierarchical power domain structures where
+      different child domains from the same provider can have different
+      parent domains.
+
 required:
   - "#power-domain-cells"
 
@@ -133,3 +148,23 @@ examples:
             min-residency-us = <7000>;
         };
     };
+
+  - |
+    // Example: SCMI domain 15 -> MAIN_PD, SCMI domain 19 -> WKUP_PD
+    MAIN_PD: power-controller-main {
+        compatible = "foo,power-controller";
+        #power-domain-cells = <0>;
+    };
+
+    WKUP_PD: power-controller-wkup {
+        compatible = "foo,power-controller";
+        #power-domain-cells = <0>;
+    };
+
+    scmi_pds: protocol@11 {
+        compatible = "foo,power-controller";
+        reg = <0x11>;
+        #power-domain-cells = <1>;
+        power-domains = <&MAIN_PD>, <&WKUP_PD>;
+        power-domains-child-ids = <15>, <19>;
+    };

-- 
2.51.0

On Tue, Mar 10, 2026 at 05:19:23PM -0700, Kevin Hilman (TI) wrote:
> Add binding documentation for the new power-domains-child-ids property,
> which works in conjunction with the existing power-domains property to
> establish parent-child relationships between a multi-domain power domain
> provider and external parent domains.
> 
> Each element in the uint32 array identifies the child domain
> ID (index) within the provider that should be made a child domain of
> the corresponding phandle entry in power-domains. The two arrays must
> have the same number of elements.
> 
> Signed-off-by: Kevin Hilman (TI) <khilman@baylibre.com>
> ---
>  Documentation/devicetree/bindings/power/power-domain.yaml | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/power/power-domain.yaml b/Documentation/devicetree/bindings/power/power-domain.yaml
> index b1147dbf2e73..a3d2af124d37 100644
> --- a/Documentation/devicetree/bindings/power/power-domain.yaml
> +++ b/Documentation/devicetree/bindings/power/power-domain.yaml
> @@ -68,6 +68,21 @@ properties:
>        by the given provider should be subdomains of the domain specified
>        by this binding.
>  
> +  power-domains-child-ids:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    description:
> +      An array of child domain IDs that correspond to the power-domains
> +      property. This property is only applicable to power domain providers
> +      with "#power-domain-cells" > 0 (i.e., providers that supply multiple
> +      power domains). It specifies which of the provider's child domains
> +      should be associated with each parent domain listed in the power-domains
> +      property. The number of elements in this array must match the number of
> +      phandles in the power-domains property. Each element specifies the child
> +      domain ID (index) that should be made a child domain of the corresponding
> +      parent domain. This enables hierarchical power domain structures where
> +      different child domains from the same provider can have different
> +      parent domains.

Okay, I guess we stick with this. Sorry for the detour.

With the example fixed,

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Rob

On Tue, 10 Mar 2026 17:19:23 -0700, Kevin Hilman (TI) wrote:
> Add binding documentation for the new power-domains-child-ids property,
> which works in conjunction with the existing power-domains property to
> establish parent-child relationships between a multi-domain power domain
> provider and external parent domains.
> 
> Each element in the uint32 array identifies the child domain
> ID (index) within the provider that should be made a child domain of
> the corresponding phandle entry in power-domains. The two arrays must
> have the same number of elements.
> 
> Signed-off-by: Kevin Hilman (TI) <khilman@baylibre.com>
> ---
>  Documentation/devicetree/bindings/power/power-domain.yaml | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/power/power-domain.example.dts:136.13-26: Warning (reg_format): /example-3/protocol@11:reg: property has invalid length (4 bytes) (#address-cells == 1, #size-cells == 1)
Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (pci_device_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (pci_device_bus_num): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (simple_bus_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (i2c_bus_reg): Failed prerequisite 'reg_format'
Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (spi_bus_reg): Failed prerequisite 'reg_format'

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260310-topic-lpm-pmdomain-child-ids-v1-1-5361687a18ff@baylibre.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

"Rob Herring (Arm)" <robh@kernel.org> writes:

> On Tue, 10 Mar 2026 17:19:23 -0700, Kevin Hilman (TI) wrote:
>> Add binding documentation for the new power-domains-child-ids property,
>> which works in conjunction with the existing power-domains property to
>> establish parent-child relationships between a multi-domain power domain
>> provider and external parent domains.
>> 
>> Each element in the uint32 array identifies the child domain
>> ID (index) within the provider that should be made a child domain of
>> the corresponding phandle entry in power-domains. The two arrays must
>> have the same number of elements.
>> 
>> Signed-off-by: Kevin Hilman (TI) <khilman@baylibre.com>
>> ---
>>  Documentation/devicetree/bindings/power/power-domain.yaml | 35 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 35 insertions(+)
>> 
>
> My bot found errors running 'make dt_binding_check' on your patch:
>
> yamllint warnings/errors:
>
> dtschema/dtc warnings/errors:
> Documentation/devicetree/bindings/power/power-domain.example.dts:136.13-26: Warning (reg_format): /example-3/protocol@11:reg: property has invalid length (4 bytes) (#address-cells == 1, #size-cells == 1)
> Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (pci_device_reg): Failed prerequisite 'reg_format'
> Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (pci_device_bus_num): Failed prerequisite 'reg_format'
> Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (simple_bus_reg): Failed prerequisite 'reg_format'
> Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (i2c_bus_reg): Failed prerequisite 'reg_format'
> Documentation/devicetree/bindings/power/power-domain.example.dtb: Warning (spi_bus_reg): Failed prerequisite 'reg_format'

Noted, and fix will be included in next rev.

Kevin