Extract GPIO pin number constants to common enum (#85)

- Move all constants for GPIO pin numbers used by components to a single
  module to avoid having conflicting numbers
- Install `num_enum` in `pod-operation`
- Use `num_enum::IntoPrimitive` to derive numeric conversion traits
  - Implements `From<Enum>` for underlying `u8` repr to use `.into()`

pod-operation/Cargo.toml

@@ -15,6 +15,7 @@ tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
 enum-map = "2.7.3"
 once_cell = "1.19.0"
+num_enum = "0.7.2"
 
 rppal = { version = "0.17.1", features = ["hal"] }
 ina219 = "0.1.0"

pod-operation/src/components/brakes.rs

@@ -1,17 +1,20 @@
+use rppal::gpio::{Gpio, OutputPin};
 use tracing::debug;
 
-use rppal::gpio::{Gpio, OutputPin};
+use crate::utils::GpioPins;
 
 pub struct Brakes {
 	pin: OutputPin,
 }
 
-const PIN_BRAKES: u8 = 26;
-
 impl Brakes {
 	pub fn new() -> Self {
 		Brakes {
-			pin: Gpio::new().unwrap().get(PIN_BRAKES).unwrap().into_output(),
+			pin: Gpio::new()
+				.unwrap()
+				.get(GpioPins::PNEUMATICS_RELAY.into())
+				.unwrap()
+				.into_output(),
 		}
 	}
 

pod-operation/src/components/high_voltage_system.rs

@@ -1,19 +1,18 @@
+use rppal::gpio::{Gpio, OutputPin};
 use tracing::debug;
 
-use rppal::gpio::{Gpio, OutputPin};
+use crate::utils::GpioPins;
 
 pub struct HighVoltageSystem {
 	pin: OutputPin,
 }
 
-const PIN_CONTACTOR_RELAY: u8 = 20;
-
 impl HighVoltageSystem {
 	pub fn new() -> Self {
 		HighVoltageSystem {
 			pin: Gpio::new()
 				.unwrap()
-				.get(PIN_CONTACTOR_RELAY)
+				.get(GpioPins::CONTACTOR_RELAY.into())
 				.unwrap()
 				.into_output(),
 		}

pod-operation/src/components/signal_light.rs

@@ -1,19 +1,18 @@
+use rppal::gpio::{Gpio, OutputPin};
 use tracing::debug;
 
-use rppal::gpio::{Gpio, OutputPin};
+use crate::utils::GpioPins;
 
 pub struct SignalLight {
 	pin: OutputPin,
 }
 
-const PIN_SIGNAL_LIGHT: u8 = 21;
-
 impl SignalLight {
 	pub fn new() -> Self {
 		SignalLight {
 			pin: Gpio::new()
 				.unwrap()
-				.get(PIN_SIGNAL_LIGHT)
+				.get(GpioPins::SIGNAL_LIGHT_RELAY.into())
 				.unwrap()
 				.into_output(),
 		}

pod-operation/src/components/wheel_encoder.rs

@@ -1,8 +1,8 @@
-use rppal::gpio::{Gpio, InputPin, Level};
 use std::time::Instant;
 
-const PIN_ENCODER_A: u8 = 1;
-const PIN_ENCODER_B: u8 = 2;
+use rppal::gpio::{Gpio, InputPin, Level};
+
+use crate::utils::GpioPins;
 
 pub struct WheelEncoder {
 	counter: f32,
@@ -20,8 +20,14 @@ impl WheelEncoder {
 		let gpio = Gpio::new().unwrap();
 		WheelEncoder {
 			counter: 0.0,
-			pin_a: gpio.get(PIN_ENCODER_A).unwrap().into_input(),
-			pin_b: gpio.get(PIN_ENCODER_B).unwrap().into_input(),
+			pin_a: gpio
+				.get(GpioPins::WHEEL_ENCODER_A.into())
+				.unwrap()
+				.into_input(),
+			pin_b: gpio
+				.get(GpioPins::WHEEL_ENCODER_B.into())
+				.unwrap()
+				.into_input(),
 			a_last_read: Level::High,
 			b_last_read: Level::Low,
 			last_distance: 0.0,

pod-operation/src/main.rs

@@ -6,6 +6,7 @@ use tracing_subscriber::FmtSubscriber;
 mod components;
 mod demo;
 mod state_machine;
+mod utils;
 
 use crate::components::brakes::Brakes;
 use crate::components::gyro::Gyroscope;

pod-operation/src/utils/gpio.rs

@@ -0,0 +1,12 @@
+#[derive(num_enum::IntoPrimitive)]
+#[repr(u8)]
+#[allow(non_camel_case_types)]
+pub enum GpioPins {
+	_RESERVED_I2C_SDA = 2,
+	_RESERVED_I2C_SCL = 3,
+	WHEEL_ENCODER_A = 23,
+	WHEEL_ENCODER_B = 24,
+	CONTACTOR_RELAY = 20,
+	SIGNAL_LIGHT_RELAY = 21,
+	PNEUMATICS_RELAY = 26,
+}

pod-operation/src/utils/mod.rs

@@ -0,0 +1,2 @@
+mod gpio;
+pub use gpio::GpioPins;