Implement embedded_hal::digital::IoPin

Author: Morgan Roff

Cargo.toml

@@ -20,7 +20,7 @@ async-tokio = ["gpio-cdev/async-tokio"]
 default = [ "gpio_cdev", "gpio_sysfs" ]
 
 [dependencies]
-embedded-hal = "=1.0.0-alpha.4"
+embedded-hal = { path = "../embedded-hal" }
 gpio-cdev = { version = "0.4", optional = true }
 sysfs_gpio = { version = "0.5", optional = true }
 

src/cdev_pin.rs

@@ -3,15 +3,33 @@
 /// Newtype around [`gpio_cdev::LineHandle`] that implements the `embedded-hal` traits
 ///
 /// [`gpio_cdev::LineHandle`]: https://docs.rs/gpio-cdev/0.2.0/gpio_cdev/struct.LineHandle.html
-pub struct CdevPin(pub gpio_cdev::LineHandle, bool);
+pub struct CdevPin(pub gpio_cdev::LineHandle, gpio_cdev::LineInfo);
 
 impl CdevPin {
     /// See [`gpio_cdev::Line::request`][0] for details.
     ///
     /// [0]: https://docs.rs/gpio-cdev/0.2.0/gpio_cdev/struct.Line.html#method.request
     pub fn new(handle: gpio_cdev::LineHandle) -> Result<Self, gpio_cdev::errors::Error> {
         let info = handle.line().info()?;
-        Ok(CdevPin(handle, info.is_active_low()))
+        Ok(CdevPin(handle, info))
+    }
+
+    fn get_input_flags(&self) -> gpio_cdev::LineRequestFlags {
+        let mut flags = gpio_cdev::LineRequestFlags::INPUT;
+        if self.1.is_active_low() {
+            flags.insert(gpio_cdev::LineRequestFlags::ACTIVE_LOW);
+        }
+        return flags;
+    }
+
+    fn get_output_flags(&self) -> gpio_cdev::LineRequestFlags {
+        let mut flags = gpio_cdev::LineRequestFlags::OUTPUT;
+        if self.1.is_open_drain() {
+            flags.insert(gpio_cdev::LineRequestFlags::OPEN_DRAIN);
+        } else if self.1.is_open_source() {
+            flags.insert(gpio_cdev::LineRequestFlags::OPEN_SOURCE);
+        }
+        return flags;
     }
 }
 
@@ -31,7 +49,7 @@ impl embedded_hal::digital::InputPin for CdevPin {
     type Error = gpio_cdev::errors::Error;
 
     fn try_is_high(&self) -> Result<bool, Self::Error> {
-        if !self.1 {
+        if !self.1.is_active_low() {
             self.0.get_value().map(|val| val != 0)
         } else {
             self.0.get_value().map(|val| val == 0)
@@ -43,6 +61,48 @@ impl embedded_hal::digital::InputPin for CdevPin {
     }
 }
 
+impl embedded_hal::digital::IoPin<CdevPin, CdevPin> for CdevPin {
+    type Error = gpio_cdev::errors::Error;
+
+    fn try_switch_to_input_pin(self) -> Result<CdevPin, Self::Error> {
+        if self.1.direction() == gpio_cdev::LineDirection::In {
+            return Ok(self);
+        }
+        let line = self.0.line().clone();
+        let input_flags = self.get_input_flags();
+        let consumer = self.1.consumer().unwrap_or("").to_owned();
+
+        // Drop self to free the line before re-requesting it in a new mode.
+        std::mem::drop(self);
+        
+        CdevPin::new(
+            line.request(
+                input_flags, 0, &consumer)?)
+    }
+
+    fn try_switch_to_output_pin(self, state: embedded_hal::digital::PinState) -> Result<CdevPin, Self::Error> {
+        if self.1.direction() == gpio_cdev::LineDirection::Out {
+            return Ok(self);
+        }
+
+        let line = self.0.line().clone();
+        let output_flags = self.get_output_flags();
+        let consumer = self.1.consumer().unwrap_or("").to_owned();
+
+        // Drop self to free the line before re-requesting it in a new mode.
+        std::mem::drop(self);
+
+        CdevPin::new(
+            line.request(
+                output_flags,
+                match state {
+                    embedded_hal::digital::PinState::High => 1,
+                    embedded_hal::digital::PinState::Low => 0,
+                },
+                &consumer)?)
+    }
+}
+
 impl core::ops::Deref for CdevPin {
     type Target = gpio_cdev::LineHandle;
 

src/sysfs_pin.rs

@@ -54,6 +54,22 @@ impl embedded_hal::digital::InputPin for SysfsPin {
     }
 }
 
+impl embedded_hal::digital::IoPin<SysfsPin, SysfsPin> for SysfsPin {
+    type Error = sysfs_gpio::Error;
+
+    fn try_switch_to_input_pin(self) -> Result<SysfsPin, Self::Error> {
+        self.set_direction(sysfs_gpio::Direction::In)?;
+        Ok(self)
+    }
+    fn try_switch_to_output_pin(self, state: embedded_hal::digital::PinState) -> Result<SysfsPin, Self::Error> {
+        self.set_direction(match state {
+            embedded_hal::digital::PinState::High => sysfs_gpio::Direction::High,
+            embedded_hal::digital::PinState::Low => sysfs_gpio::Direction::Low,
+        })?;
+        Ok(self)
+    }
+}
+
 impl core::ops::Deref for SysfsPin {
     type Target = sysfs_gpio::Pin;