blob: 1b0936a5beec350e1fff10ad60fc4bfaa75400e0 [file] [log] [blame]
# SPDX-License-Identifier: GPL-2.0-only
%YAML 1.2
title: PowerPC sleep property
- Rob Herring <>
description: |
Devices on SOCs often have mechanisms for placing devices into low-power
states that are decoupled from the devices' own register blocks. Sometimes,
this information is more complicated than a cell-index property can
reasonably describe. Thus, each device controlled in such a manner
may contain a "sleep" property which describes these connections.
The sleep property consists of one or more sleep resources, each of
which consists of a phandle to a sleep controller, followed by a
controller-specific sleep specifier of zero or more cells.
The semantics of what type of low power modes are possible are defined
by the sleep controller. Some examples of the types of low power modes
that may be supported are:
- Dynamic: The device may be disabled or enabled at any time.
- System Suspend: The device may request to be disabled or remain
awake during system suspend, but will not be disabled until then.
- Permanent: The device is disabled permanently (until the next hard
Some devices may share a clock domain with each other, such that they should
only be suspended when none of the devices are in use. Where reasonable,
such nodes should be placed on a virtual bus, where the bus has the sleep
property. If the clock domain is shared among devices that cannot be
reasonably grouped in this manner, then create a virtual sleep controller
(similar to an interrupt nexus, except that defining a standardized
sleep-map should wait until its necessity is demonstrated).
select: true
$ref: /schemas/types.yaml#/definitions/phandle-array
additionalProperties: true