Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | # SPDX-License-Identifier: GPL-2.0-only |
| 2 | %YAML 1.2 |
| 3 | --- |
| 4 | $id: http://devicetree.org/schemas/powerpc/sleep.yaml# |
| 5 | $schema: http://devicetree.org/meta-schemas/core.yaml# |
| 6 | |
| 7 | title: PowerPC sleep property |
| 8 | |
| 9 | maintainers: |
| 10 | - Rob Herring <robh@kernel.org> |
| 11 | |
| 12 | description: | |
| 13 | Devices on SOCs often have mechanisms for placing devices into low-power |
| 14 | states that are decoupled from the devices' own register blocks. Sometimes, |
| 15 | this information is more complicated than a cell-index property can |
| 16 | reasonably describe. Thus, each device controlled in such a manner |
| 17 | may contain a "sleep" property which describes these connections. |
| 18 | |
| 19 | The sleep property consists of one or more sleep resources, each of |
| 20 | which consists of a phandle to a sleep controller, followed by a |
| 21 | controller-specific sleep specifier of zero or more cells. |
| 22 | |
| 23 | The semantics of what type of low power modes are possible are defined |
| 24 | by the sleep controller. Some examples of the types of low power modes |
| 25 | that may be supported are: |
| 26 | |
| 27 | - Dynamic: The device may be disabled or enabled at any time. |
| 28 | - System Suspend: The device may request to be disabled or remain |
| 29 | awake during system suspend, but will not be disabled until then. |
| 30 | - Permanent: The device is disabled permanently (until the next hard |
| 31 | reset). |
| 32 | |
| 33 | Some devices may share a clock domain with each other, such that they should |
| 34 | only be suspended when none of the devices are in use. Where reasonable, |
| 35 | such nodes should be placed on a virtual bus, where the bus has the sleep |
| 36 | property. If the clock domain is shared among devices that cannot be |
| 37 | reasonably grouped in this manner, then create a virtual sleep controller |
| 38 | (similar to an interrupt nexus, except that defining a standardized |
| 39 | sleep-map should wait until its necessity is demonstrated). |
| 40 | |
| 41 | select: true |
| 42 | |
| 43 | properties: |
| 44 | sleep: |
| 45 | $ref: /schemas/types.yaml#/definitions/phandle-array |
| 46 | |
| 47 | additionalProperties: true |