Port example to stm32f4xx-hal version 0.6

* Switch to the `embedded_hal::digital::v2::OutputPin` trait
* Handle all infallable `set_low`/`set_high` calls within the
  `led_ring` module

Cargo.toml

@@ -20,7 +20,7 @@ version = "0.5.0"
 
 [dependencies.hal]
 package = "stm32f4xx-hal"
-version = "0.3.0"
+version = "0.6.0"
 features = ["rt", "stm32f407"]
 
 [lib]

src/led_ring.rs

@@ -1,6 +1,7 @@
 //! Module for manipulating the LED ring.
 
-use hal::prelude::_embedded_hal_digital_OutputPin as OutputPin;
+use core::convert::Infallible;
+use hal::prelude::_embedded_hal_digital_v2_OutputPin as OutputPin;
 
 /// The cycle direction of the LED ring.
 ///
@@ -52,7 +53,7 @@ pub struct LedRing<LED> {
 
 impl<LED> LedRing<LED>
 where
-    LED: OutputPin,
+    LED: OutputPin<Error = Infallible>,
 {
     /// Sets up the LED ring using using four LED GPIO outputs.
     pub fn from(leds: [LED; 4]) -> LedRing<LED> {
@@ -114,8 +115,8 @@ where
     pub fn advance(&mut self) {
         let num_leds = self.leds.len();
 
-        self.leds[self.index].set_high();
-        self.leds[(self.index + 2) % num_leds].set_low();
+        self.leds[self.index].set_high().unwrap();
+        self.leds[(self.index + 2) % num_leds].set_low().unwrap();
 
         self.index = match self.direction {
             Direction::Clockwise => (self.index + 1) % num_leds,
@@ -128,7 +129,7 @@ where
     /// This is done immediately, regardless of the current mode.
     pub fn all_on(&mut self) {
         for led in self.leds.iter_mut() {
-            led.set_high();
+            led.set_high().unwrap();
         }
     }
 
@@ -137,7 +138,7 @@ where
     /// This is done immediately, regardless of the current mode.
     pub fn all_off(&mut self) {
         for led in self.leds.iter_mut() {
-            led.set_low();
+            led.set_low().unwrap();
         }
     }
 
@@ -148,9 +149,9 @@ where
     pub fn specific_on(&mut self, directions: [bool; 4]) {
         for (led, on_off) in self.leds.iter_mut().zip(directions.iter()) {
             if *on_off {
-                led.set_high();
+                led.set_high().unwrap();
             } else {
-                led.set_low();
+                led.set_low().unwrap();
             }
         }
     }
@@ -164,7 +165,7 @@ where
 
 #[cfg(test)]
 mod tests {
-    use super::{Direction, LedRing, Mode, OutputPin};
+    use super::{Direction, Infallible, LedRing, Mode, OutputPin};
 
     #[derive(Debug, Eq, PartialEq)]
     struct MockOutputPin {
@@ -183,12 +184,16 @@ mod tests {
     }
 
     impl OutputPin for MockOutputPin {
-        fn set_high(&mut self) {
+        type Error = Infallible;
+
+        fn set_high(&mut self) -> Result<(), Self::Error> {
             self.state = true;
+            Ok(())
         }
 
-        fn set_low(&mut self) {
+        fn set_low(&mut self) -> Result<(), Self::Error> {
             self.state = false;
+            Ok(())
         }
     }
 

src/main.rs

@@ -108,9 +108,9 @@ const APP: () = {
         let mut accel_cs = gpioe.pe3.into_push_pull_output();
 
         // Initialize the accelerometer.
-        accel_cs.set_low();
+        accel_cs.set_low().unwrap();
         let _ = accel.transfer(&mut [0x20, 0b01000111]).unwrap();
-        accel_cs.set_high();
+        accel_cs.set_high().unwrap();
 
         // Output to the serial interface that initialisation is finished.
         writeln!(serial_tx, "init\r").unwrap();
@@ -150,13 +150,13 @@ const APP: () = {
     /// and schedules the next trigger (if enabled).
     #[task(schedule = [accel_leds], resources = [accel, accel_cs, led_ring, serial_tx])]
     fn accel_leds(mut cx: accel_leds::Context) {
-        cx.resources.accel_cs.set_low();
+        cx.resources.accel_cs.set_low().unwrap();
         let read_command = (1 << 7) | (1 << 6) | 0x29;
         let mut commands = [read_command, 0x0, 0x0, 0x0];
         let result = cx.resources.accel.transfer(&mut commands[..]).unwrap();
         let acc_x = result[1] as i8;
         let acc_y = result[3] as i8;
-        cx.resources.accel_cs.set_high();
+        cx.resources.accel_cs.set_high().unwrap();
 
         if acc_x == 0 && acc_y == 0 {
             cx.resources