hal: add optional defmt support.

.github/workflows/test.yml

@@ -24,13 +24,18 @@ jobs:
           - thumbv6m-none-eabi
           - thumbv7m-none-eabi
         include:
+          - target: thumbv7m-none-eabi
+            features: defmt-03
           - target: x86_64-unknown-linux-gnu
             features: std
           - target: x86_64-unknown-linux-gnu
             features: alloc
           - target: x86_64-unknown-linux-gnu
             features: std,tokio-1,futures-03
             rust: nightly
+          - target: x86_64-unknown-linux-gnu
+            features: std,tokio-1,futures-03,defmt-03
+            rust: nightly
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@master

embedded-hal-async/Cargo.toml

@@ -14,5 +14,9 @@ repository = "https://github.com/rust-embedded/embedded-hal"
 version = "0.2.0-alpha.2"
 rust-version = "1.65.0"
 
+[features]
+defmt-03 = ["dep:defmt-03", "embedded-hal/defmt-03"]
+
 [dependencies]
 embedded-hal = { version = "=1.0.0-alpha.11", path = "../embedded-hal" }
+defmt-03 = { package = "defmt", version = "0.3", optional = true }

embedded-hal-bus/Cargo.toml

@@ -16,11 +16,13 @@ version = "0.1.0-alpha.3"
 [features]
 std = []
 async = ["dep:embedded-hal-async"]
+defmt-03 = ["dep:defmt-03", "embedded-hal/defmt-03", "embedded-hal-async?/defmt-03"]
 
 [dependencies]
 embedded-hal = { version = "=1.0.0-alpha.11", path = "../embedded-hal" }
 embedded-hal-async = { version = "=0.2.0-alpha.2", path = "../embedded-hal-async", optional = true }
 critical-section = { version = "1.0" }
+defmt-03 = { package = "defmt", version = "0.3", optional = true }
 
 [package.metadata.docs.rs]
 features = ["std", "async"]

embedded-hal-bus/src/lib.rs

@@ -4,5 +4,9 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![cfg_attr(feature = "async", feature(async_fn_in_trait, impl_trait_projections))]
 
+// needed to prevent defmt macros from breaking, since they emit code that does `defmt::blahblah`.
+#[cfg(feature = "defmt-03")]
+use defmt_03 as defmt;
+
 pub mod i2c;
 pub mod spi;

embedded-hal-bus/src/spi/mod.rs

@@ -14,8 +14,12 @@ pub use mutex::*;
 mod critical_section;
 pub use self::critical_section::*;
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// Error type for [`ExclusiveDevice`] operations.
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum DeviceError<BUS, CS> {
     /// An inner SPI bus operation failed
     Spi(BUS),
@@ -37,6 +41,8 @@ where
 }
 
 /// Dummy `DelayUs` implementation that panics on use.
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub struct NoDelay;
 
 #[cold]

embedded-hal/Cargo.toml

@@ -14,3 +14,6 @@ name = "embedded-hal"
 readme = "README.md"
 repository = "https://github.com/rust-embedded/embedded-hal"
 version = "1.0.0-alpha.11"
+
+[dependencies]
+defmt-03 = { package = "defmt", version = "0.3", optional = true }

embedded-hal/src/digital.rs

@@ -2,6 +2,9 @@
 
 use core::{convert::From, ops::Not};
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// Error
 pub trait Error: core::fmt::Debug {
     /// Convert error to a generic error kind
@@ -24,6 +27,7 @@ impl Error for core::convert::Infallible {
 /// free to define more specific or additional error types. However, by providing
 /// a mapping to these common errors, generic code can still react to them.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum ErrorKind {
     /// A different error occurred. The original error may contain more information.
@@ -74,6 +78,7 @@ impl<T: ErrorType + ?Sized> ErrorType for &mut T {
 /// assert_eq!(!state, PinState::High);
 /// ```
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum PinState {
     /// Low pin state
     Low,

embedded-hal/src/i2c.rs

@@ -154,6 +154,9 @@
 
 use crate::private;
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// I2C error
 pub trait Error: core::fmt::Debug {
     /// Convert error to a generic I2C error kind
@@ -176,6 +179,7 @@ impl Error for core::convert::Infallible {
 /// free to define more specific or additional error types. However, by providing
 /// a mapping to these common I2C errors, generic code can still react to them.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum ErrorKind {
     /// Bus error occurred. e.g. A START or a STOP condition is detected and is not
@@ -199,6 +203,7 @@ pub enum ErrorKind {
 /// response was received to an address versus a no acknowledge to a data byte.
 /// Where it is not possible to differentiate, `Unknown` should be indicated.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum NoAcknowledgeSource {
     /// The device did not acknowledge its address. The device may be missing.
     Address,
@@ -272,6 +277,7 @@ impl AddressMode for TenBitAddress {}
 ///
 /// Several operations can be combined as part of a transaction.
 #[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum Operation<'a> {
     /// Read data into the provided buffer
     Read(&'a mut [u8]),

embedded-hal/src/lib.rs

@@ -15,3 +15,7 @@ mod private {
     impl Sealed for SevenBitAddress {}
     impl Sealed for TenBitAddress {}
 }
+
+// needed to prevent defmt macros from breaking, since they emit code that does `defmt::blahblah`.
+#[cfg(feature = "defmt-03")]
+use defmt_03 as defmt;

embedded-hal/src/pwm.rs

@@ -1,5 +1,8 @@
 //! Pulse Width Modulation (PWM) traits
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// Error
 pub trait Error: core::fmt::Debug {
     /// Convert error to a generic error kind
@@ -22,6 +25,7 @@ impl Error for core::convert::Infallible {
 /// free to define more specific or additional error types. However, by providing
 /// a mapping to these common errors, generic code can still react to them.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum ErrorKind {
     /// A different error occurred. The original error may contain more information.

embedded-hal/src/spi.rs

@@ -163,8 +163,12 @@
 
 use core::fmt::Debug;
 
+#[cfg(feature = "defmt-03")]
+use crate::defmt;
+
 /// Clock polarity
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum Polarity {
     /// Clock signal low when idle
     IdleLow,
@@ -174,6 +178,7 @@ pub enum Polarity {
 
 /// Clock phase
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum Phase {
     /// Data in "captured" on the first clock transition
     CaptureOnFirstTransition,
@@ -183,6 +188,7 @@ pub enum Phase {
 
 /// SPI mode
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub struct Mode {
     /// Clock polarity
     pub polarity: Polarity,
@@ -236,6 +242,7 @@ impl Error for core::convert::Infallible {
 /// free to define more specific or additional error types. However, by providing
 /// a mapping to these common SPI errors, generic code can still react to them.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum ErrorKind {
     /// The peripheral receive buffer was overrun
@@ -295,7 +302,8 @@ impl<T: ErrorType + ?Sized> ErrorType for &mut T {
 /// SPI transaction operation.
 ///
 /// This allows composition of SPI operations into a single bus transaction
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
 pub enum Operation<'a, Word: 'static> {
     /// Read data into the provided buffer.
     ///