From 002d0b0d1685473f0f81cd17346d119fc671ad9c Mon Sep 17 00:00:00 2001
From: datdenkikniet <jcdra1@gmail.com>
Date: Wed, 15 Feb 2023 23:21:52 +0100
Subject: [PATCH] Make embedded-hal-async dependency optional for better
 compatibility with HALs

Some hals implement traits for embedded-hal version `=1.0.0.alpha.<not 9>`, which is
explicitly incompatible with the version `=1.0.0.alpha.9` which embedded-hal-async
depends on. Making the dependency optional allows downstream projects to include
rtic-monotonic without requiring that all of their other libraries also implement
that specific version of embedded-hal 1.0
---
 rtic-monotonics/Cargo.toml     | 2 +-
 rtic-monotonics/src/rp2040.rs  | 4 ++--
 rtic-monotonics/src/systick.rs | 4 ++--
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/rtic-monotonics/Cargo.toml b/rtic-monotonics/Cargo.toml
index 0c942a20d7..d60b68cb9f 100644
--- a/rtic-monotonics/Cargo.toml
+++ b/rtic-monotonics/Cargo.toml
@@ -18,7 +18,7 @@ license = "MIT OR Apache-2.0"
 
 [dependencies]
 rtic-time = { version = "1.0.0-alpha.0", path = "../rtic-time" }
-embedded-hal-async = "0.2.0-alpha.0"
+embedded-hal-async = { version = "0.2.0-alpha.0", optional = true }
 fugit = { version = "0.3.6" }
 atomic-polyfill = "1"
 cfg-if = "1.0.0"
diff --git a/rtic-monotonics/src/rp2040.rs b/rtic-monotonics/src/rp2040.rs
index 064a50df69..e42c148e4c 100644
--- a/rtic-monotonics/src/rp2040.rs
+++ b/rtic-monotonics/src/rp2040.rs
@@ -3,7 +3,6 @@
 use super::Monotonic;
 pub use super::{TimeoutError, TimerQueue};
 use core::future::Future;
-use embedded_hal_async::delay::DelayUs;
 pub use fugit::ExtU64;
 use rp2040_pac::{timer, Interrupt, RESETS, TIMER};
 
@@ -116,7 +115,8 @@ impl Monotonic for Timer {
     fn disable_timer() {}
 }
 
-impl DelayUs for Timer {
+#[cfg(feature = "embedded-hal-async")]
+impl embedded_hal_async::delay::DelayUs for Timer {
     type Error = core::convert::Infallible;
 
     async fn delay_us(&mut self, us: u32) -> Result<(), Self::Error> {
diff --git a/rtic-monotonics/src/systick.rs b/rtic-monotonics/src/systick.rs
index 885da925b4..27110220a3 100644
--- a/rtic-monotonics/src/systick.rs
+++ b/rtic-monotonics/src/systick.rs
@@ -5,7 +5,6 @@ pub use super::{TimeoutError, TimerQueue};
 use atomic_polyfill::{AtomicU32, Ordering};
 use core::future::Future;
 use cortex_m::peripheral::SYST;
-use embedded_hal_async::delay::DelayUs;
 pub use fugit::ExtU32;
 
 // Features should be additive, here systick_100hz gets picked if both
@@ -136,7 +135,8 @@ impl Monotonic for Systick {
     fn disable_timer() {}
 }
 
-impl DelayUs for Systick {
+#[cfg(feature = "embedded-hal-async")]
+impl embedded_hal_async::delay::DelayUs for Systick {
     type Error = core::convert::Infallible;
 
     async fn delay_us(&mut self, us: u32) -> Result<(), Self::Error> {