fuchsia.hardware.power

PowerElementConfiguration and types contained in that struct define the configuration that drivers can expect from board drivers. This configuration information is intended to be reflected into the power management system by the receivers of that configuration.

PowerTokenService is what drivers should implement to provide their children with access to the driver's power elements.

PROTOCOLS

Device

Defined in fuchsia.hardware.power/power.fidl

GetCurrentVoltage

Get current voltage in uV.

Request

Name	Type
index	uint32

Response

Name	Type
payload	Device_GetCurrentVoltage_Result

GetPowerDomainStatus

Get power domain status

Request

<EMPTY>

Response

Name	Type
payload	Device_GetPowerDomainStatus_Result

GetSupportedVoltageRange

Get Supported Voltage Range. min and max are in micorVolts(uV)

Request

<EMPTY>

Response

Name	Type
payload	Device_GetSupportedVoltageRange_Result

ReadPmicCtrlReg

Read ctrl register of PMIC

Request

Name	Type
reg_addr	uint32

Response

Name	Type
payload	Device_ReadPmicCtrlReg_Result

RegisterPowerDomain

Register the callee for this power domain. The callee will be registered until UnregisterPowerDomain is called. Any voltage changes to the power domain will be made considering the min_needed_voltage(in uV) and max_supported_voltage(in uV) published here. If voltages mentioned are out of supported voltage range of domain(obtained by calling GetSupportedVoltageRange), the callee will be registered with the supported voltage range.

Request

Name	Type
min_needed_voltage	uint32
max_supported_voltage	uint32

Response

Name	Type
payload	Device_RegisterPowerDomain_Result

RequestVoltage

Request a particular voltage. The actual_voltage is the voltage that the power domain is transitioned to after considering supported voltage ranges of all the registered dependents. "voltage" should be in uV.

Request

Name	Type
voltage	uint32

Response

Name	Type
payload	Device_RequestVoltage_Result

UnregisterPowerDomain

Unregister the callee for this power domain. The callee will no longer be considered as a dependent of this power domain.

Request

<EMPTY>

Response

Name	Type
payload	Device_UnregisterPowerDomain_Result

WritePmicCtrlReg

Write to ctrl register of PMIC

Request

Name	Type
reg_addr	uint32
value	uint32

Response

Name	Type
payload	Device_WritePmicCtrlReg_Result

PowerTokenProvider

Defined in fuchsia.hardware.power/config.fidl

GetToken

Returns a token which can be used with fuchsia.power.broker APIs to create a relationship between this driver's power element(s) and the power element this token is associated with.

Request

<EMPTY>

Response

Name	Type
payload	PowerTokenProvider_GetToken_Result

STRUCTS

ComponentPowerConfiguration

Defined in fuchsia.hardware.power/config.fidl

The configuration for a component's power elements.

Field	Type	Description	Default
power_elements	vector<PowerElementConfiguration>:32		No default

Device_GetCurrentVoltage_Response

Defined in fuchsia.hardware.power/power.fidl

Field	Type	Description	Default
current_voltage	uint32		No default

Device_GetPowerDomainStatus_Response

Defined in fuchsia.hardware.power/power.fidl

Field	Type	Description	Default
status	PowerDomainStatus		No default

Device_GetSupportedVoltageRange_Response

Defined in fuchsia.hardware.power/power.fidl

Field	Type	Description	Default
min	uint32		No default
max	uint32		No default

Device_ReadPmicCtrlReg_Response

Defined in fuchsia.hardware.power/power.fidl

Field	Type	Description	Default
value	uint32		No default

Device_RegisterPowerDomain_Response

Defined in fuchsia.hardware.power/power.fidl

<EMPTY>

Device_RequestVoltage_Response

Defined in fuchsia.hardware.power/power.fidl

Field	Type	Description	Default
actual_voltage	uint32		No default

Device_UnregisterPowerDomain_Response

Defined in fuchsia.hardware.power/power.fidl

<EMPTY>

Device_WritePmicCtrlReg_Response

Defined in fuchsia.hardware.power/power.fidl

<EMPTY>

PowerTokenProvider_GetToken_Response resource

Defined in fuchsia.hardware.power/config.fidl

Field	Type	Description	Default
handle	handle<event>		No default

ENUMS

CpuPowerElement strict

Type: uint32

Defined in fuchsia.hardware.power/config.fidl

Represents the power elements related to controlling the CPU. This is an enum with a single variant to add flexibility for future addition of more elements related to CPU power state.

Name	Value	Description
CPU	1

PowerDomainStatus strict

Type: uint8

Defined in fuchsia.hardware.power/power.fidl

Name	Value	Description
DISABLED	1
ENABLED	2

RequirementType strict

Type: uint32

Defined in fuchsia.hardware.power/config.fidl

Name	Value	Description
ASSERTIVE	1
OPPORTUNISTIC	2

SagElement strict

Type: uint32

Defined in fuchsia.hardware.power/config.fidl

Name	Value	Description
EXECUTION_STATE	1
WAKE_HANDLING	3
APPLICATION_ACTIVITY	4

TABLES

Domain

Defined in fuchsia.hardware.power/metadata.fidl

Information related to a power domain.

Ordinal	Field	Type	Description
1	id	uint32	Domain ID should be unique across all power domains in the same level. Used to associate power consumers that belong to the same power domain.

DomainMetadata

Defined in fuchsia.hardware.power/metadata.fidl

Passed to the power core driver in metadata as DEVICE_METADATA_POWER_DOMAINS.

Ordinal	Field	Type	Description
1	domains	vector<Domain>	List of power domains to be managed by this power driver.

LevelTuple

Defined in fuchsia.hardware.power/config.fidl

Represents a dependency between two power levels of two different PowerElements.

Ordinal	Field	Type	Description
1	child_level	uint8
2	parent_level	uint8

PowerDependency

Defined in fuchsia.hardware.power/config.fidl

Describes the relationship between the PowerLevels of two PowerElements. child is the name of the PowerElement which has PowerLevels that depend on parent.

• child is the name for a PowerElement which a driver owns.
• parent is the name for a PowerElement which a driver has access to
• level_deps is the map of level dependencies from child to parent.

Ordinal	Field	Type	Description
1	child	string:63
2	parent	ParentElement
3	level_deps	vector<LevelTuple>:128
4	strength	RequirementType

PowerElement

Defined in fuchsia.hardware.power/config.fidl

Set of PowerLevels and a human-readable identifier. A PowerLevel itself contains information about valid transitions out of that level.

Ordinal	Field	Type	Description
1	name	string:63
2	levels	vector<PowerLevel>:128

PowerElementConfiguration

Defined in fuchsia.hardware.power/config.fidl

Contains the PowerElement description and any dependencies it has on other PowerElements.

Ordinal	Field	Type	Description
1	element	PowerElement
2	dependencies	vector<PowerDependency>:128

PowerLevel

Defined in fuchsia.hardware.power/config.fidl

A zero-indexed set of levels that a device can assume.

• level is the zero-indexed level of this PowerLevel.
• name is a human-readable label for this PowerLevel, used only for debugging.
• transitions describes the levels that are valid transitions from this PowerLevel.

Ordinal	Field	Type	Description
1	level	uint8
2	name	string:63
3	transitions	vector<Transition>:127

Transition

Defined in fuchsia.hardware.power/config.fidl

The length of time it takes to move to a power level.

• target_level is the power level we're moving to.
• latency_us is the time it takes to move to the level in microseconds.

Ordinal	Field	Type	Description
1	target_level	uint8
2	latency_us	uint32

UNIONS

Device_GetCurrentVoltage_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_GetCurrentVoltage_Response
2	err	zx/Status

Device_GetPowerDomainStatus_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_GetPowerDomainStatus_Response
2	err	zx/Status

Device_GetSupportedVoltageRange_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_GetSupportedVoltageRange_Response
2	err	zx/Status

Device_ReadPmicCtrlReg_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_ReadPmicCtrlReg_Response
2	err	zx/Status

Device_RegisterPowerDomain_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_RegisterPowerDomain_Response
2	err	zx/Status

Device_RequestVoltage_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_RequestVoltage_Response
2	err	zx/Status

Device_UnregisterPowerDomain_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_UnregisterPowerDomain_Response
2	err	zx/Status

Device_WritePmicCtrlReg_Result strict

Defined in fuchsia.hardware.power/power.fidl

Ordinal	Variant	Type	Description
1	response	Device_WritePmicCtrlReg_Response
2	err	zx/Status

ParentElement strict

Defined in fuchsia.hardware.power/config.fidl

Identifier for an element that is another element's parent, in other words an element that the other element depends upon.

Ordinal	Variant	Type	Description
1	sag	SagElement	The parent element is one of SAG's elements and the access token should be obtained from the appropriate SAG-related protocol.
2	instance_name	string:63	The parent element's access token should be available from /svc/fuchsia.hardware.power.PowerTokenProvider/{instance_name}.
3	cpu_control	CpuPowerElement	The parent element comes from the fuchsia.power.system/CpuElementManager protocol.

PowerTokenProvider_GetToken_Result strict resource

Defined in fuchsia.hardware.power/config.fidl

Ordinal	Variant	Type	Description
1	response	PowerTokenProvider_GetToken_Response
2	err	zx/Status
3	framework_err	internal

CONSTANTS

Name	Value	Type	Description
MAX_DEPENDENCIES	128	uint16
MAX_LEVELS	128	uint16	Should be MAX_TRANSITIONS + 1
MAX_NAME_LENGTH	63	uint16
MAX_POWER_ELEMENTS	32	uint16
MAX_TRANSITIONS	127	uint16	This means we could have up to 128 power levels, which seems like more than enough.

SERVICES

PowerTokenService

Defined in fuchsia.hardware.power/config.fidl

Name	Type	Transport
token_provider	fuchsia.hardware.power/PowerTokenProvider	Channel

Service

Defined in fuchsia.hardware.power/power.fidl

Name	Type	Transport
device	fuchsia.hardware.power/Device	Channel