Add explicit types for WHO_AM_I values. (#15)

* Add explicit types for `WHO_AM_I` values. * Add changelog entry. * Rename method device ID is_correct * Update CHANGELOG.md Co-authored-by: Diego Barrios Romero <eldruin@gmail.com>
eldruin · Aug 10, 2022 · 01883f9 · 01883f9
1 parent 5f40ea9
commit 01883f9
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - [breaking-change] Simplify API by using explicit types for each measurement.
 - Minimum supported Rust version has been upgraded to 1.54.0.
 - Pass delay into functions to handle turn-on times.
+- Add explicit types for accelerometer and magnetometer IDs.
 
 ## [0.2.2] - 2021-09-21
 

diff --git a/src/device_impl.rs b/src/device_impl.rs
@@ -1,9 +1,7 @@
 use crate::{
     interface::{I2cInterface, ReadData, SpiInterface, WriteData},
-    mode,
-    register_address::{WHO_AM_I_A_VAL, WHO_AM_I_M_VAL},
-    Acceleration, BitFlags as BF, Config, Error, Lsm303agr, PhantomData, Register, Status,
-    Temperature, TemperatureStatus,
+    mode, Acceleration, AccelerometerId, BitFlags as BF, Config, Error, Lsm303agr, MagnetometerId,
+    PhantomData, Register, Status, Temperature, TemperatureStatus,
 };
 
 impl<I2C> Lsm303agr<I2cInterface<I2C>, mode::MagOneShot> {
@@ -131,24 +129,16 @@ where
             .map(Status::new)
     }
 
-    /// Get accelerometer device ID
-    pub fn accelerometer_id(&mut self) -> Result<u8, Error<CommE, PinE>> {
-        self.iface.read_accel_register(Register::WHO_AM_I_A)
+    /// Get the accelerometer device ID.
+    pub fn accelerometer_id(&mut self) -> Result<AccelerometerId, Error<CommE, PinE>> {
+        let id = self.iface.read_accel_register(Register::WHO_AM_I_A)?;
+        Ok(AccelerometerId { raw: id })
     }
 
-    /// Read and verify the accelerometer device ID
-    pub fn accelerometer_is_detected(&mut self) -> Result<bool, Error<CommE, PinE>> {
-        Ok(self.accelerometer_id()? == WHO_AM_I_A_VAL)
-    }
-
-    /// Get magnetometer device ID
-    pub fn magnetometer_id(&mut self) -> Result<u8, Error<CommE, PinE>> {
-        self.iface.read_mag_register(Register::WHO_AM_I_M)
-    }
-
-    /// Read and verify the magnetometer device ID
-    pub fn magnetometer_is_detected(&mut self) -> Result<bool, Error<CommE, PinE>> {
-        Ok(self.magnetometer_id()? == WHO_AM_I_M_VAL)
+    /// Get the magnetometer device ID.
+    pub fn magnetometer_id(&mut self) -> Result<MagnetometerId, Error<CommE, PinE>> {
+        let id = self.iface.read_mag_register(Register::WHO_AM_I_M)?;
+        Ok(MagnetometerId { raw: id })
     }
 
     /// Get measured temperature.

diff --git a/src/lib.rs b/src/lib.rs
@@ -123,8 +123,9 @@ mod mag_mode_change;
 mod magnetometer;
 mod types;
 pub use crate::types::{
-    mode, AccelMode, AccelOutputDataRate, AccelScale, Acceleration, Error, MagOutputDataRate,
-    MagneticField, ModeChangeError, Status, Temperature, TemperatureStatus,
+    mode, AccelMode, AccelOutputDataRate, AccelScale, Acceleration, AccelerometerId, Error,
+    MagOutputDataRate, MagneticField, MagnetometerId, ModeChangeError, Status, Temperature,
+    TemperatureStatus,
 };
 mod register_address;
 use crate::register_address::{BitFlags, Register};

diff --git a/src/types.rs b/src/types.rs
@@ -1,5 +1,7 @@
 use bitflags::bitflags;
 
+use crate::register_address::{WHO_AM_I_A_VAL, WHO_AM_I_M_VAL};
+
 /// All possible errors in this crate
 #[derive(Debug)]
 pub enum Error<CommE, PinE> {
@@ -30,6 +32,24 @@ pub mod mode {
     pub enum MagContinuous {}
 }
 
+/// An Accelerometer ID.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct AccelerometerId {
+    pub(crate) raw: u8,
+}
+
+impl AccelerometerId {
+    /// Raw accelerometer ID.
+    pub const fn raw(&self) -> u8 {
+        self.raw
+    }
+
+    /// Check if the ID corresponds to the expected value.
+    pub const fn is_correct(&self) -> bool {
+        self.raw == WHO_AM_I_A_VAL
+    }
+}
+
 /// An acceleration measurement.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub struct Acceleration {
@@ -127,6 +147,24 @@ impl Acceleration {
     }
 }
 
+/// A Magnetometer ID.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct MagnetometerId {
+    pub(crate) raw: u8,
+}
+
+impl MagnetometerId {
+    /// Raw magnetometer ID.
+    pub const fn raw(&self) -> u8 {
+        self.raw
+    }
+
+    /// Check if the ID corresponds to the expected value.
+    pub const fn is_correct(&self) -> bool {
+        self.raw == WHO_AM_I_M_VAL
+    }
+}
+
 /// A magnetic field measurement.
 #[derive(Debug, Default, Clone, Copy, PartialEq)]
 pub struct MagneticField {

diff --git a/tests/integration.rs b/tests/integration.rs
@@ -20,86 +20,107 @@ fn can_create_and_destroy_spi() {
 }
 
 #[test]
-fn i2c_can_get_accel_id() {
-    let accel_id = 0xAB;
+fn i2c_acc_id_is_not_correct() {
+    let acc_id = 0xAB;
     let mut sensor = new_i2c(&[I2cTrans::write_read(
         ACCEL_ADDR,
         vec![Register::WHO_AM_I_A],
-        vec![accel_id],
+        vec![acc_id],
     )]);
     let id = sensor.accelerometer_id().unwrap();
-    assert_eq!(accel_id, id);
+
+    assert_eq!(id.raw(), acc_id);
+    assert!(!id.is_correct());
+
     destroy_i2c(sensor);
 }
 
 #[test]
-fn i2c_accelerometer_is_detected() {
-    let accel_id = 0x33;
+fn i2c_acc_id_is_correct() {
+    let acc_id = 0x33;
     let mut sensor = new_i2c(&[I2cTrans::write_read(
         ACCEL_ADDR,
         vec![Register::WHO_AM_I_A],
-        vec![accel_id],
+        vec![acc_id],
     )]);
-    assert!(sensor.accelerometer_is_detected().unwrap());
+    let id = sensor.accelerometer_id().unwrap();
+
+    assert_eq!(id.raw(), acc_id);
+    assert!(id.is_correct());
+
     destroy_i2c(sensor);
 }
 
 #[test]
-fn i2c_can_get_mag_id() {
+fn i2c_mag_id_is_not_correct() {
     let mag_id = 0xAB;
     let mut sensor = new_i2c(&[I2cTrans::write_read(
         MAG_ADDR,
         vec![Register::WHO_AM_I_M],
         vec![mag_id],
     )]);
     let id = sensor.magnetometer_id().unwrap();
-    assert_eq!(mag_id, id);
+
+    assert_eq!(id.raw(), mag_id);
+    assert!(!id.is_correct());
+
     destroy_i2c(sensor);
 }
 
 #[test]
-fn i2c_magnetometer_is_detected() {
+fn i2c_mag_id_is_correct() {
     let mag_id = 0x40;
     let mut sensor = new_i2c(&[I2cTrans::write_read(
         MAG_ADDR,
         vec![Register::WHO_AM_I_M],
         vec![mag_id],
     )]);
-    assert!(sensor.magnetometer_is_detected().unwrap());
+    let id = sensor.magnetometer_id().unwrap();
+
+    assert_eq!(id.raw(), mag_id);
+    assert!(id.is_correct());
+
     destroy_i2c(sensor);
 }
 
 #[test]
-fn spi_can_get_accel_id() {
-    let accel_id = 0xAB;
+fn spi_acc_id_is_not_correct() {
+    let acc_id = 0xAB;
     let mut sensor = new_spi_accel(
         &[SpiTrans::transfer(
             vec![BF::SPI_RW | Register::WHO_AM_I_A, 0],
-            vec![0, accel_id],
+            vec![0, acc_id],
         )],
         default_cs(),
     );
     let id = sensor.accelerometer_id().unwrap();
-    assert_eq!(accel_id, id);
+
+    assert_eq!(id.raw(), acc_id);
+    assert!(!id.is_correct());
+
     destroy_spi(sensor);
 }
 
 #[test]
-fn spi_accelerometer_is_detected() {
-    let accel_id = 0x33;
+fn spi_acc_id_is_correct() {
+    let acc_id = 0x33;
     let mut sensor = new_spi_accel(
         &[SpiTrans::transfer(
             vec![BF::SPI_RW | Register::WHO_AM_I_A, 0],
-            vec![0, accel_id],
+            vec![0, acc_id],
         )],
         default_cs(),
     );
-    assert!(sensor.accelerometer_is_detected().unwrap());
+    let id = sensor.accelerometer_id().unwrap();
+
+    assert_eq!(id.raw(), acc_id);
+    assert!(id.is_correct());
+
     destroy_spi(sensor);
 }
 
 #[test]
-fn spi_can_get_mag_id() {
+fn spi_mag_id_is_not_correct() {
     let mag_id = 0xAB;
     let mut sensor = new_spi_mag(
         &[SpiTrans::transfer(
@@ -109,12 +130,15 @@ fn spi_can_get_mag_id() {
         default_cs(),
     );
     let id = sensor.magnetometer_id().unwrap();
-    assert_eq!(mag_id, id);
+
+    assert_eq!(id.raw(), mag_id);
+    assert!(!id.is_correct());
+
     destroy_spi(sensor);
 }
 
 #[test]
-fn spi_magnetometer_is_detected() {
+fn spi_mag_id_is_correct() {
     let mag_id = 0x40;
     let mut sensor = new_spi_mag(
         &[SpiTrans::transfer(
@@ -123,7 +147,11 @@ fn spi_magnetometer_is_detected() {
         )],
         default_cs(),
     );
-    assert!(sensor.magnetometer_is_detected().unwrap());
+    let id = sensor.magnetometer_id().unwrap();
+
+    assert_eq!(id.raw(), mag_id);
+    assert!(id.is_correct());
+
     destroy_spi(sensor);
 }