Merge pull request #115 from ia0/polyfill

Support architectures without atomics with polyfill

Author: eldruin

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 * New enums and allocators for Isochronous endpoints ([#60](https://github.com/rust-embedded-community/usb-device/pull/60)).
 * Ability to select USB revision ([#116](https://github.com/rust-embedded-community/usb-device/pull/116)).
 * Added support for alternate settings on interfaces ([#114](https://github.com/rust-embedded-community/usb-device/pull/114)).
+* Added support for architectures without atomics ([#115](https://github.com/rust-embedded-community/usb-device/pull/115)).
 
 ### Changed
 * `EndpointType` enum now has fields for isochronous synchronization and usage ([#60](https://github.com/rust-embedded-community/usb-device/pull/60)).

Cargo.toml

@@ -11,6 +11,7 @@ repository = "https://github.com/mvirkkunen/usb-device"
 
 [dependencies]
 defmt = { version = "0.3", optional = true }
+portable-atomic = { version = "1.2.0", default-features = false }
 
 [dev-dependencies]
 rusb = "0.9.1"

src/bus.rs

@@ -6,7 +6,7 @@ use crate::{Result, UsbDirection, UsbError};
 use core::cell::RefCell;
 use core::mem;
 use core::ptr;
-use core::sync::atomic::{AtomicPtr, Ordering};
+use portable_atomic::{AtomicPtr, Ordering};
 
 /// A trait for device-specific USB peripherals. Implement this to add support for a new hardware
 /// platform.

src/endpoint.rs

@@ -1,7 +1,7 @@
 use crate::bus::UsbBus;
 use crate::{Result, UsbDirection};
 use core::marker::PhantomData;
-use core::sync::atomic::{AtomicPtr, Ordering};
+use portable_atomic::{AtomicPtr, Ordering};
 
 /// Trait for endpoint type markers.
 pub trait EndpointDirection {