Add async support

.github/workflows/build.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [stable, 1.62.0]
+        rust: [stable, 1.75.0]
         TARGET:
           - x86_64-unknown-linux-gnu
           - x86_64-unknown-linux-musl
@@ -108,4 +108,4 @@ jobs:
         uses: coverallsapp/github-action@master
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
-          path-to-lcov: './lcov.info'
+          path-to-lcov: './lcov.info'

CHANGELOG.md

@@ -10,10 +10,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 - Added `Display`, `Error` and common trait implementations for `Error<E>`.
 - Added common trait implementations for types.
+- Async support based on `embedded-hal-async` 1.0 behind `async` feature flag.
 
 ### Changed
 - [breaking-change] Removed `Default` implementation for `Pca9685` struct.
-- Raised MSRV to 1.62.0.
+- Raised MSRV to 1.75.0.
 - [breaking-change] Updated `embedded-hal` dependency to 1.0.
 
 ## [0.3.1] - 2021-07-14

Cargo.toml

@@ -23,6 +23,8 @@ edition = "2018"
 [dependencies]
 embedded-hal = "1.0"
 nb = "1"
+embedded-hal-async = { version = "1", optional = true }
+maybe-async-cfg = "0.2.3"
 
 [dev-dependencies]
 linux-embedded-hal = "0.4"
@@ -33,3 +35,4 @@ lto = true
 
 [features]
 std = []
+async = ["dep:embedded-hal-async"]

README.md

@@ -2,14 +2,16 @@
 
 [![crates.io](https://img.shields.io/crates/v/pwm-pca9685.svg)](https://crates.io/crates/pwm-pca9685)
 [![Docs](https://docs.rs/pwm-pca9685/badge.svg)](https://docs.rs/pwm-pca9685)
-![Minimum Supported Rust Version](https://img.shields.io/badge/rustc-1.62+-blue.svg)
+![Minimum Supported Rust Version](https://img.shields.io/badge/rustc-1.75+-blue.svg)
 [![Build Status](https://github.com/eldruin/pwm-pca9685-rs/workflows/Build/badge.svg)](https://github.com/eldruin/pwm-pca9685-rs/actions?query=workflow%3ABuild)
 [![Coverage Status](https://coveralls.io/repos/github/eldruin/pwm-pca9685-rs/badge.svg?branch=master)](https://coveralls.io/github/eldruin/pwm-pca9685-rs?branch=master)
 
 This is a platform agnostic Rust driver for the PCA9685 PWM/Servo/LED
 controller, based on the [`embedded-hal`] traits.
+This driver also supports the [`embedded-hal-async`] traits if the `async` feature is enabled.
 
 [`embedded-hal`]: https://github.com/rust-embedded/embedded-hal
+[`embedded-hal-async`]: https://github.com/rust-embedded/embedded-hal-async
 
 This driver allows you to:
 - Enable/disable the device. See: `enable()`.
@@ -91,6 +93,53 @@ fn main() {
 }
 ```
 
+The same settings, but async with the [Embassy](https://embassy.dev/) framework on an RP2040:
+
+```toml
+# Cargo.toml
+pwm-pca9685 = { version = "0.3.1", features = ["async"] }
+```
+
+```rust
+#![no_std]
+#![no_main]
+
+use embassy_executor::Spawner;
+use embassy_rp::{bind_interrupts, i2c};
+use embassy_rp::peripherals::I2C0;
+use embassy_time::Timer;
+use panic_halt as _;
+use pwm_pca9685::{Address, Channel, Pca9685};
+
+bind_interrupts!(struct Irqs {
+    I2C0_IRQ => i2c::InterruptHandler<I2C0>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let i2c = i2c::I2c::new_async(p.I2C0, p.PIN_1, p.PIN_0, Irqs, i2c::Config::default());
+
+    let address = Address::default();
+    let mut pwm = Pca9685::new(dev, address).await.unwrap();
+
+    // This corresponds to a frequency of 60 Hz.
+    pwm.set_prescale(100).await.unwrap();
+
+    // It is necessary to enable the device.
+    pwm.enable().await.unwrap();
+
+    // Turn on channel 0 at 0.
+    pwm.set_channel_on(Channel::C0, 0).await.unwrap();
+
+    // Turn off channel 0 at 2047, which is 50% in
+    // the range `[0..4095]`.
+    pwm.set_channel_off(Channel::C0, 2047).await.unwrap();
+
+    let _dev = pwm.destroy(); // Get the I2C device back
+}
+```
+
 ## Support
 
 For questions, issues, feature requests, and other changes, please file an

src/channels.rs

@@ -1,37 +1,50 @@
-use crate::{hal, Channel, Error, Pca9685, Register};
+use crate::{Channel, Error, Pca9685, Register};
 
+#[cfg(not(feature = "async"))]
+use embedded_hal::i2c::I2c;
+#[cfg(feature = "async")]
+use embedded_hal_async::i2c::I2c as AsyncI2c;
+
+#[maybe_async_cfg::maybe(
+    sync(
+        cfg(not(feature = "async")),
+        self = "Pca9685",
+        idents(AsyncI2c(sync = "I2c"))
+    ),
+    async(feature = "async", keep_self)
+)]
 impl<I2C, E> Pca9685<I2C>
 where
-    I2C: hal::i2c::I2c<Error = E>,
+    I2C: AsyncI2c<Error = E>,
 {
     /// Set the `ON` counter for the selected channel.
     ///
     /// Note that the full off setting takes precedence over the `on` settings.
     /// See section 7.3.3 "LED output and PWM control" of the datasheet for
     /// further details.
-    pub fn set_channel_on(&mut self, channel: Channel, value: u16) -> Result<(), Error<E>> {
+    pub async fn set_channel_on(&mut self, channel: Channel, value: u16) -> Result<(), Error<E>> {
         if value > 4095 {
             return Err(Error::InvalidInputData);
         }
         let reg = get_register_on(channel);
-        self.write_double_register(reg, value)
+        self.write_double_register(reg, value).await
     }
 
     /// Set the `OFF` counter for the selected channel.
-    pub fn set_channel_off(&mut self, channel: Channel, value: u16) -> Result<(), Error<E>> {
+    pub async fn set_channel_off(&mut self, channel: Channel, value: u16) -> Result<(), Error<E>> {
         if value > 4095 {
             return Err(Error::InvalidInputData);
         }
         let reg = get_register_off(channel);
-        self.write_double_register(reg, value)
+        self.write_double_register(reg, value).await
     }
 
     /// Set the `ON` and `OFF` counters for the selected channel.
     ///
     /// Note that the full off setting takes precedence over the `on` settings.
     /// See section 7.3.3 "LED output and PWM control" of the datasheet for
     /// further details.
-    pub fn set_channel_on_off(
+    pub async fn set_channel_on_off(
         &mut self,
         channel: Channel,
         on: u16,
@@ -41,7 +54,7 @@ where
             return Err(Error::InvalidInputData);
         }
         let reg = get_register_on(channel);
-        self.write_two_double_registers(reg, on, off)
+        self.write_two_double_registers(reg, on, off).await
     }
 
     /// Set the channel always on.
@@ -51,13 +64,17 @@ where
     ///
     /// See section 7.3.3 "LED output and PWM control" of the datasheet for
     /// further details.
-    pub fn set_channel_full_on(&mut self, channel: Channel, value: u16) -> Result<(), Error<E>> {
+    pub async fn set_channel_full_on(
+        &mut self,
+        channel: Channel,
+        value: u16,
+    ) -> Result<(), Error<E>> {
         if value > 4095 {
             return Err(Error::InvalidInputData);
         }
         let reg = get_register_on(channel);
         let value = value | 0b0001_0000_0000_0000;
-        self.write_double_register(reg, value)
+        self.write_double_register(reg, value).await
     }
 
     /// Set the channel always off.
@@ -67,10 +84,10 @@ where
     ///
     /// See section 7.3.3 "LED output and PWM control" of the datasheet for
     /// further details.
-    pub fn set_channel_full_off(&mut self, channel: Channel) -> Result<(), Error<E>> {
+    pub async fn set_channel_full_off(&mut self, channel: Channel) -> Result<(), Error<E>> {
         let reg = get_register_off(channel);
         let value = 0b0001_0000_0000_0000;
-        self.write_double_register(reg, value)
+        self.write_double_register(reg, value).await
     }
 
     /// Set the `ON` and `OFF` counter for each channel at once.
@@ -79,7 +96,11 @@ where
     /// Note that the full off setting takes precedence over the `on` settings.
     /// See section 7.3.3 "LED output and PWM control" of the datasheet for
     /// further details.
-    pub fn set_all_on_off(&mut self, on: &[u16; 16], off: &[u16; 16]) -> Result<(), Error<E>> {
+    pub async fn set_all_on_off(
+        &mut self,
+        on: &[u16; 16],
+        off: &[u16; 16],
+    ) -> Result<(), Error<E>> {
         let mut data = [0; 65];
         data[0] = Register::C0_ON_L;
         for (i, (on, off)) in on.iter().zip(off).enumerate() {
@@ -91,8 +112,11 @@ where
             data[i * 4 + 3] = *off as u8;
             data[i * 4 + 4] = (*off >> 8) as u8;
         }
-        self.enable_auto_increment()?;
-        self.i2c.write(self.address, &data).map_err(Error::I2C)
+        self.enable_auto_increment().await?;
+        self.i2c
+            .write(self.address, &data)
+            .await
+            .map_err(Error::I2C)
     }
 }