Struct PowerManager 

pub struct PowerManager<C: PowerController = NoController> { /* private fields */ }

Power manager for controlling system power state.

Hardware support (read this)

Real power transitions — dynamic CPU-frequency scaling and peripheral clock/power gating for HighPerformance / Balanced / LowPower / UltraLowPower / DeepSleep — are SoC-vendor-specific and require a BSP-provided PowerController. This manager never fabricates vendor-register writes; it delegates every transition to the installed controller.

The type parameter records which controller is installed:

• PowerManager::new builds a PowerManager<NoController>: a bookkeeping-only manager. Transitions are validated and the requested mode is recorded (so current_mode always reflects the last successful request), but no hardware is touched for the four active modes. This is honest by construction — the type is PowerManager<NoController> and has_hardware_controller returns false.
• PowerManager::with_controller builds a PowerManager<C> around a real BSP controller; request_mode then delegates to PowerController::set_power_mode and propagates its result.

Sleep modes

For PowerMode::Sleep and PowerMode::DeepSleep the manager, after delegating to the controller, additionally issues the ISA-level WFI (wait-for-interrupt) on arm/aarch64 and riscv targets. WFI really halts the core in a low-power state until a wake event and is target-generic (not SoC-specific), so it lives here rather than in the controller. On other targets it is a no-op.

Requiring real hardware

Callers that must not proceed without silicon-level control should use request_mode_strict, which returns EmbeddedError::NoPowerController when only a NoController is installed instead of silently recording a mode that never reached hardware.

Implementations

impl PowerManager<NoController>

pub const fn new() -> Self

Create a new bookkeeping-only power manager in high performance mode.

The manager holds a NoController, so transitions are recorded but no hardware is reconfigured. Use with_controller to install a BSP-provided PowerController for real transitions.

impl<C: PowerController> PowerManager<C>

pub const fn with_controller(controller: C) -> Self

Create a power manager backed by a BSP-provided PowerController, starting in high performance mode.

Every subsequent transition delegates to controller.

pub const fn controller(&self) -> &C

Borrow the installed power controller.

pub fn has_hardware_controller(&self) -> bool

Whether a real hardware PowerController is installed.

Returns false for the default NoController and true for any controller that does not override PowerController::is_hardware to false.

pub fn current_mode(&self) -> PowerMode

Get current power mode.

pub fn request_mode(&self, mode: PowerMode) -> Result<()>

Request a power mode transition.

The requested mode is validated and recorded, then applied through the installed PowerController. With the default NoController the mode is recorded but no hardware is reconfigured (see the type-level docs); with a BSP controller the transition is delegated to PowerController::set_power_mode and its result is propagated. For sleep modes the ISA-level WFI is issued afterwards on arm/riscv.

If you must not proceed without real hardware control, use request_mode_strict instead.

Errors

Returns EmbeddedError::PowerModeTransitionFailed if the transition is not allowed, or any error surfaced by the installed controller.

pub fn request_mode_strict(&self, mode: PowerMode) -> Result<()>

Request a power mode transition, failing loudly if there is no real hardware controller.

Identical to request_mode except that it returns EmbeddedError::NoPowerController — without recording the mode or touching hardware — when only a bookkeeping NoController is installed. Use this when a silent no-op would be a correctness bug (for example, before entering a mode your application depends on for thermal or battery limits).

Errors

Returns EmbeddedError::NoPowerController if no hardware controller is installed, otherwise behaves like request_mode.

Trait Implementations

impl Default for PowerManager<NoController>

fn default() -> Self

Returns the “default value” for a type.