Humidity API

Cargo.toml

@@ -26,6 +26,7 @@ libtock_proximity = { path = "apis/proximity" }
 libtock_runtime = { path = "runtime" }
 libtock_sound_pressure = {path = "apis/sound_pressure"}
 libtock_temperature = { path = "apis/temperature" }
+libtock_humidity = { path = "apis/humidity" }
 
 [profile.dev]
 panic = "abort"
@@ -46,6 +47,7 @@ members = [
     "apis/buttons",
     "apis/buzzer",
     "apis/console",
+    "apis/humidity",
     "apis/leds",
     "apis/low_level_debug",
     "apis/ninedof",

apis/humidity/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "libtock_humidity"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+libtock_platform = { path = "../../platform" }
+
+[dev-dependencies]
+libtock_unittest = { path = "../../unittest" }

apis/humidity/src/lib.rs

@@ -0,0 +1,88 @@
+#![no_std]
+
+use core::cell::Cell;
+use libtock_platform::{
+    share, subscribe::OneId, DefaultConfig, ErrorCode, Subscribe, Syscalls, Upcall,
+};
+
+pub struct Humidity<S: Syscalls>(S);
+
+impl<S: Syscalls> Humidity<S> {
+    /// Returns Ok() if the driver was present.This does not necessarily mean
+    /// that the driver is working.
+    pub fn exists() -> Result<(), ErrorCode> {
+        S::command(DRIVER_NUM, EXISTS, 0, 0).to_result()
+    }
+
+    /// Initiate a humidity measurement.
+    ///
+    /// This function is used both for synchronous and asynchronous readings
+    pub fn read() -> Result<(), ErrorCode> {
+        S::command(DRIVER_NUM, READ_HUM, 0, 0).to_result()
+    }
+
+    /// Register an events listener
+    pub fn register_listener<'share, F: Fn(u32)>(
+        listener: &'share HumidityListener<F>,
+        subscribe: share::Handle<Subscribe<'share, S, DRIVER_NUM, 0>>,
+    ) -> Result<(), ErrorCode> {
+        S::subscribe::<_, _, DefaultConfig, DRIVER_NUM, 0>(subscribe, listener)
+    }
+
+    /// Unregister the events listener
+    pub fn unregister_listener() {
+        S::unsubscribe(DRIVER_NUM, 0)
+    }
+
+    /// Initiate a synchronous humidity measurement.
+    /// Returns Ok(humidity_value) if the operation was successful
+    /// humidity_value is returned in hundreds of percent
+    pub fn read_sync() -> Result<u32, ErrorCode> {
+        let humidity_cell: Cell<Option<u32>> = Cell::new(None);
+        let listener = HumidityListener(|humidity_val| {
+            humidity_cell.set(Some(humidity_val));
+        });
+        share::scope(|subscribe| {
+            Self::register_listener(&listener, subscribe)?;
+            Self::read()?;
+            while humidity_cell.get() == None {
+                S::yield_wait();
+            }
+
+            match humidity_cell.get() {
+                None => Err(ErrorCode::Busy),
+                Some(humidity_val) => Ok(humidity_val),
+            }
+        })
+    }
+}
+
+/// A wrapper around a closure to be registered and called when
+/// a humidity reading is done.
+///
+/// ```ignore
+/// let listener = HumidityListener(|humidity_val| {
+///     // make use of the humidity value
+/// });
+/// ```
+pub struct HumidityListener<F: Fn(u32)>(pub F);
+
+impl<F: Fn(u32)> Upcall<OneId<DRIVER_NUM, 0>> for HumidityListener<F> {
+    fn upcall(&self, humidity: u32, _arg1: u32, _arg2: u32) {
+        self.0(humidity)
+    }
+}
+
+#[cfg(test)]
+mod tests;
+
+// -----------------------------------------------------------------------------
+// Driver number and command IDs
+// -----------------------------------------------------------------------------
+
+const DRIVER_NUM: u32 = 0x60001;
+
+// Command IDs
+
+const EXISTS: u32 = 0;
+const READ_HUM: u32 = 1;

apis/humidity/src/tests.rs

@@ -0,0 +1,73 @@
+use core::cell::Cell;
+use libtock_platform::{share, ErrorCode, Syscalls, YieldNoWaitReturn};
+use libtock_unittest::fake;
+
+use crate::HumidityListener;
+
+type Humidity = super::Humidity<fake::Syscalls>;
+
+#[test]
+fn no_driver() {
+    let _kernel = fake::Kernel::new();
+    assert_eq!(Humidity::exists(), Err(ErrorCode::NoDevice));
+}
+
+#[test]
+fn driver_check() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Humidity::new();
+    kernel.add_driver(&driver);
+
+    assert_eq!(Humidity::exists(), Ok(()));
+}
+
+#[test]
+fn read_humidity() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Humidity::new();
+    kernel.add_driver(&driver);
+
+    assert_eq!(Humidity::read(), Ok(()));
+    assert!(driver.is_busy());
+
+    assert_eq!(Humidity::read(), Err(ErrorCode::Busy));
+    assert_eq!(Humidity::read_sync(), Err(ErrorCode::Busy));
+}
+
+#[test]
+fn register_unregister_listener() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Humidity::new();
+    kernel.add_driver(&driver);
+
+    let humidity_cell: Cell<Option<u32>> = Cell::new(None);
+    let listener = HumidityListener(|val| {
+        humidity_cell.set(Some(val));
+    });
+    share::scope(|subscribe| {
+        assert_eq!(Humidity::read(), Ok(()));
+        driver.set_value(100);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::NoUpcall);
+
+        assert_eq!(Humidity::register_listener(&listener, subscribe), Ok(()));
+        assert_eq!(Humidity::read(), Ok(()));
+        driver.set_value(100);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::Upcall);
+        assert_eq!(humidity_cell.get(), Some(100));
+
+        Humidity::unregister_listener();
+        assert_eq!(Humidity::read(), Ok(()));
+        driver.set_value(100);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::NoUpcall);
+    });
+}
+
+#[test]
+fn read_humidity_sync() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Humidity::new();
+    kernel.add_driver(&driver);
+
+    driver.set_value_sync(1000);
+    assert_eq!(Humidity::read_sync(), Ok(1000));
+}

examples/humidity.rs

@@ -0,0 +1,37 @@
+//! A simple libtock-rs example. Checks for humidity driver
+//! and samples the sensor every 2 seconds.
+
+#![no_main]
+#![no_std]
+
+use core::fmt::Write;
+use libtock::console::Console;
+
+use libtock::alarm::{Alarm, Milliseconds};
+use libtock::humidity::Humidity;
+use libtock::runtime::{set_main, stack_size};
+
+set_main! {main}
+stack_size! {0x200}
+
+fn main() {
+    if Humidity::exists().is_err() {
+        writeln!(Console::writer(), "humidity driver unavailable").unwrap();
+        return;
+    }
+
+    loop {
+        match Humidity::read_sync() {
+            Ok(hum_val) => writeln!(
+                Console::writer(),
+                "Humidity: {}.{}%\n",
+                hum_val / 100,
+                hum_val % 100
+            )
+            .unwrap(),
+            Err(_) => writeln!(Console::writer(), "error while reading humidity",).unwrap(),
+        }
+
+        Alarm::sleep_for(Milliseconds(2000)).unwrap();
+    }
+}

src/lib.rs

@@ -44,6 +44,13 @@ pub mod gpio {
         PullDown, PullNone, PullUp,
     };
 }
+
+pub mod humidity {
+    use libtock_humidity as humidity;
+    pub type Humidity = humidity::Humidity<super::runtime::TockSyscalls>;
+    pub use humidity::HumidityListener;
+}
+
 pub mod leds {
     use libtock_leds as leds;
     pub type Leds = leds::Leds<super::runtime::TockSyscalls>;

unittest/src/fake/humidity/mod.rs

@@ -0,0 +1,85 @@
+//! Fake implementation of the Humidity API, documented here:
+//! https://github.com/tock/tock/blob/master/doc/syscalls/60001_humidity.md
+//!
+//! Like the real API, `Humidity` controls a fake humidity sensor. It provides
+//! a function `set_value` used to immediately call an upcall with a humidity value read by the sensor
+//! and a function 'set_value_sync' used to call the upcall when the read command is received.
+
+use crate::{DriverInfo, DriverShareRef};
+use libtock_platform::{CommandReturn, ErrorCode};
+use std::cell::Cell;
+
+// The `upcall_on_command` field is set to Some(value) if an upcall(with value as its argument) should be called when read command is received,
+// or None otherwise. It was needed for testing `read_sync` library function which simulates a synchronous humidity read,
+// because it was impossible to schedule an upcall during the `synchronous` read in other ways.
+pub struct Humidity {
+    busy: Cell<bool>,
+    upcall_on_command: Cell<Option<i32>>,
+    share_ref: DriverShareRef,
+}
+
+impl Humidity {
+    pub fn new() -> std::rc::Rc<Humidity> {
+        std::rc::Rc::new(Humidity {
+            busy: Cell::new(false),
+            upcall_on_command: Cell::new(None),
+            share_ref: Default::default(),
+        })
+    }
+
+    pub fn is_busy(&self) -> bool {
+        self.busy.get()
+    }
+    pub fn set_value(&self, value: i32) {
+        if self.busy.get() {
+            self.share_ref
+                .schedule_upcall(0, (value as u32, 0, 0))
+                .expect("Unable to schedule upcall");
+            self.busy.set(false);
+        }
+    }
+    pub fn set_value_sync(&self, value: i32) {
+        self.upcall_on_command.set(Some(value));
+    }
+}
+
+impl crate::fake::SyscallDriver for Humidity {
+    fn info(&self) -> DriverInfo {
+        DriverInfo::new(DRIVER_NUM).upcall_count(1)
+    }
+
+    fn register(&self, share_ref: DriverShareRef) {
+        self.share_ref.replace(share_ref);
+    }
+
+    fn command(&self, command_id: u32, _argument0: u32, _argument1: u32) -> CommandReturn {
+        match command_id {
+            EXISTS => crate::command_return::success(),
+
+            READ_HUM => {
+                if self.busy.get() {
+                    return crate::command_return::failure(ErrorCode::Busy);
+                }
+                self.busy.set(true);
+                if let Some(val) = self.upcall_on_command.take() {
+                    self.set_value(val);
+                }
+                crate::command_return::success()
+            }
+            _ => crate::command_return::failure(ErrorCode::NoSupport),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests;
+// -----------------------------------------------------------------------------
+// Driver number and command IDs
+// -----------------------------------------------------------------------------
+
+const DRIVER_NUM: u32 = 0x60001;
+
+// Command IDs
+
+const EXISTS: u32 = 0;
+const READ_HUM: u32 = 1;

unittest/src/fake/humidity/tests.rs

@@ -0,0 +1,67 @@
+use crate::fake::{self, SyscallDriver};
+use fake::humidity::*;
+use libtock_platform::{share, DefaultConfig, YieldNoWaitReturn};
+
+//Test the command implementation
+#[test]
+fn command() {
+    let hum = Humidity::new();
+
+    assert!(hum.command(EXISTS, 1, 2).is_success());
+
+    assert!(hum.command(READ_HUM, 0, 0).is_success());
+
+    assert_eq!(
+        hum.command(READ_HUM, 0, 0).get_failure(),
+        Some(ErrorCode::Busy)
+    );
+
+    hum.set_value(100);
+    assert!(hum.command(READ_HUM, 0, 1).is_success());
+    hum.set_value(100);
+
+    hum.set_value_sync(100);
+    assert!(hum.command(READ_HUM, 0, 1).is_success());
+    assert!(hum.command(READ_HUM, 0, 1).is_success());
+}
+
+// Integration test that verifies Humidity works with fake::Kernel and
+// libtock_platform::Syscalls.
+#[test]
+fn kernel_integration() {
+    use libtock_platform::Syscalls;
+    let kernel = fake::Kernel::new();
+    let hum = Humidity::new();
+    kernel.add_driver(&hum);
+    assert!(fake::Syscalls::command(DRIVER_NUM, EXISTS, 1, 2).is_success());
+    assert!(fake::Syscalls::command(DRIVER_NUM, READ_HUM, 0, 0).is_success());
+    assert_eq!(
+        fake::Syscalls::command(DRIVER_NUM, READ_HUM, 0, 0).get_failure(),
+        Some(ErrorCode::Busy)
+    );
+    hum.set_value(100);
+    assert!(fake::Syscalls::command(DRIVER_NUM, READ_HUM, 0, 1).is_success());
+
+    let listener = Cell::<Option<(u32,)>>::new(None);
+    share::scope(|subscribe| {
+        assert_eq!(
+            fake::Syscalls::subscribe::<_, _, DefaultConfig, DRIVER_NUM, 0>(subscribe, &listener),
+            Ok(())
+        );
+
+        hum.set_value(100);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::Upcall);
+        assert_eq!(listener.get(), Some((100,)));
+
+        hum.set_value(200);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::NoUpcall);
+
+        assert!(fake::Syscalls::command(DRIVER_NUM, READ_HUM, 0, 1).is_success());
+        hum.set_value(200);
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::Upcall);
+
+        hum.set_value_sync(200);
+        assert!(fake::Syscalls::command(DRIVER_NUM, READ_HUM, 0, 1).is_success());
+        assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::Upcall);
+    });
+}