DAC: Add wrapper around RIOTs DAC-interface

Merges: #36

.github/workflows/buildtest.yml

@@ -37,7 +37,7 @@ jobs:
       # update` is much faster the second time (so a parallel execution may
       # still be faster but uses 3x the resources)
       run: |
-        export BOARDS='native sltb001a samr21-xpro'
+        export BOARDS='native sltb001a samr21-xpro stk3700'
         DIRS='examples/rust-hello-world examples/rust-gcoap tests/rust_minimal'
         # It appears that there has to be output before :: commands really catch on
         echo "Building ${DIRS} on ${BOARDS}"
@@ -56,7 +56,7 @@ jobs:
         echo "::echo ::off"
     - name: Build and run tests
       run: |
-        export BOARDS='native sltb001a samr21-xpro'
+        export BOARDS='native sltb001a samr21-xpro stk3700'
         DIRS=$(echo tests/*/)
         export RIOTBASE=$(pwd)/RIOT
         # It appears that there has to be output before :: commands really catch on

src/dac.rs

@@ -0,0 +1,65 @@
+use riot_sys::dac_t;
+
+#[derive(Debug)]
+pub struct DACLine {
+    line: dac_t,
+}
+
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum DACError {
+    /// The given dac_t line did not exist
+    NoLine,
+    /// An unknown error did occur
+    Unknown,
+}
+
+impl DACLine {
+    /// Creates and intializes a new [`DACLine`].
+    ///
+    /// The `index` indicates which dac device from the current board should be used.
+    /// For information on how many such devices are available for this board please
+    /// refer to its RIOT documentation.
+    ///
+    /// Returns an Error if the given line does not exist
+    /// on the board.
+    pub fn new(index: usize) -> Result<Self, DACError> {
+        let line = unsafe { riot_sys::macro_DAC_LINE(index as u32) };
+        let res = unsafe { riot_sys::dac_init(line) } as i32;
+
+        const DAC_OK: i32 = riot_sys::DAC_OK as i32;
+        const DAC_NOLINE: i32 = riot_sys::DAC_NOLINE as i32;
+
+        match res {
+            DAC_OK => Ok(DACLine { line }),
+            DAC_NOLINE => Err(DACError::NoLine),
+            _ => Err(DACError::Unknown),
+        }
+    }
+
+    /// Builds a [`DACLine`] from an already initialized [`dac_t`].
+    ///
+    /// Providing a not initialized [`dac_t`] results in undefined behavior.
+    pub unsafe fn new_without_init(line: dac_t) -> Self {
+        DACLine { line }
+    }
+
+    /// Writes the given value to this [`DACLine`]
+    ///
+    /// The `value` is internally scaled to the underlying
+    /// dac device so that the maximum voltage output
+    /// is always equivalent to [`u16::MAX`]
+    pub fn set(&mut self, value: u16) {
+        unsafe { riot_sys::dac_set(self.line, value) }
+    }
+
+    /// Turns the [`DACLine`] on after `DACLine::power_off`
+    pub fn power_on(&mut self) {
+        unsafe { riot_sys::dac_poweron(self.line) }
+    }
+
+    /// Turns the [`DACLine`] off
+    pub fn power_off(&mut self) {
+        unsafe { riot_sys::dac_poweroff(self.line) }
+    }
+}

src/lib.rs

@@ -118,6 +118,9 @@ pub mod spi;
 #[cfg(riot_module_periph_adc)]
 pub mod adc;
 
+#[cfg(riot_module_periph_dac)]
+pub mod dac;
+
 #[cfg(riot_module_ztimer)]
 pub mod ztimer;
 

tests/dac/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "riot-wrappers-test-dac"
+version = "0.1.0"
+authors = ["Christian Amsüss <chrysn@fsfe.org>"]
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["staticlib"]
+
+[profile.release]
+panic = "abort"
+
+[dependencies]
+riot-wrappers = { version = "*", features = [ "set_panic_handler" ] }
+riot-sys = "*"
+
+[patch.crates-io]
+riot-sys = { git = "https://github.com/RIOT-OS/rust-riot-sys" }

tests/dac/Makefile

@@ -0,0 +1,14 @@
+# name of your application
+APPLICATION = riot-wrappers-test-dac
+APPLICATION_RUST_MODULE = riot_wrappers_test_dac
+BASELIBS += $(APPLICATION_RUST_MODULE).module
+FEATURES_REQUIRED += rust_target
+FEATURES_REQUIRED += periph_dac
+
+# Of these boards it is known that DAC0 may be driven arbitrarily because it's
+# just a pin on the extension header. (It's probably true for most boards, but
+# so far nobody guarantees that. Just add your board here if your DAC0 pin is
+# good to use).
+BOARD_WHITELIST = stk3700
+
+include $(RIOTBASE)/Makefile.include

tests/dac/src/lib.rs

@@ -0,0 +1,11 @@
+#![no_std]
+
+use riot_wrappers::dac;
+use riot_wrappers::riot_main;
+
+riot_main!(main);
+
+fn main() {
+    let mut dac = dac::DACLine::new(0).unwrap();
+    dac.set(655); // 1% of maximum value
+}