hal::error

One error type an application can ? into.

Every subsystem keeps its own small enum — a bus timeout is not a Wi-Fi refusal, and a driver should say precisely what went wrong. But an application that talks to three of them does not want three map_err closures per function. [Error] is the sum of those enums, with a From per subsystem so ? converts, plus the handful of failures that belong to no subsystem in particular (NotInitialised, WrongDevice, …).

Drivers outside hal add impl From<TheirError> for hal::Error at the bottom of their crate; a driver with nothing more specific to say maps to [Error::Other] with a static message.

Enums

ConnectError

enum ConnectError {
    Route,
    AlreadyRegistered,
    NoneFree,
}

Why a peripheral’s interrupt could not be delivered to a handler.

Returned by the kernel’s interrupt::connect; the enum lives here so a driver can name it without naming the kernel.

Implements: Clone, Copy, Debug, Display, Eq, From, PartialEq, StructuralPartialEq

Error

enum Error {
    Bus(crate::bus::BusError),
    Wifi(crate::wifi::WifiError),
    Dma(crate::dma::DmaError),
    Interrupt(ConnectError),
    NotInitialised,
    Unsupported,
    WrongDevice { expected: u8, found: u8 },
    Other(&'static str),
}

The one error an application sees.

Implements: Clone, Copy, Debug, Display, Eq, From, PartialEq, StructuralPartialEq

References: BusError, ConnectError, DmaError, WifiError

Type Aliases

Result

type Result<T> = core::result::Result<T, Error>;

A result whose error is [Error].

References: Error