LEDs: Expose presence

.github/workflows/test.yml

@@ -34,6 +34,7 @@ jobs:
       with:
         repository: RIOT-OS/RIOT
         path: RIOT
+    # common steps end here
     - name: Patch .cargo/config.toml to use current checkout
       run: |
         set -x
@@ -59,7 +60,6 @@ jobs:
             cargo tree --manifest-path $MANIF
             echo "::endgroup::"
         done
-    # common steps end here
 
     - name: Build the example
       run: |
@@ -91,40 +91,22 @@ jobs:
         board: [native, sltb001a, samr21-xpro, stk3700]
         testdir: ${{ fromJSON(needs.enumerate-wrappers-tests.outputs.list) }}
     steps:
-    # common steps start here
+    # common steps start here (kept in sync even though we wouldn't need to patch RIOT's .cargo/config.toml)
     - name: Check out riot-wrappers
       uses: actions/checkout@v3
     - name: Check out RIOT
       uses: actions/checkout@v3
       with:
         repository: RIOT-OS/RIOT
         path: RIOT
-    - name: Patch .cargo/config.toml to use current checkout
+    # common steps end here
+
+    - name: Patch local .cargo/config.toml to use current checkout
       run: |
-        set -x
-        cd RIOT
-        rm -f .cargo/config.toml
-        mkdir -p .cargo # Keep working if RIOT ever decides it doesn't need overrides any more
+        mkdir .cargo
         echo '[patch.crates-io]' >> .cargo/config.toml
-        echo 'riot-wrappers = { path = "../", version = "*" }' >> .cargo/config.toml
+        echo 'riot-wrappers = { path = ".", version = "*" }' >> .cargo/config.toml
         echo 'riot-sys = { git = "https://github.com/RIOT-OS/rust-riot-sys" }' >> .cargo/config.toml
-    - name: Pull cargo updates
-      # No sense in running this in parallel -- this will download the index
-      # and all relevant crates once, and after that, just make some notes in Cargo.lock
-      run: |
-        set -x
-        # It is important to cd in early, for otherwise the patch.crates-io
-        # will not catch on during the update
-        cd RIOT
-        for MANIF in $(find -name Cargo.toml)
-        do
-            echo "::group::Updating ${MANIF}"
-            cargo update -p riot-sys -p riot-wrappers --aggressive --manifest-path $MANIF
-            cargo fetch --manifest-path $MANIF
-            cargo tree --manifest-path $MANIF
-            echo "::endgroup::"
-        done
-    # common steps end here
 
     - name: Build and run test
       run: |

Cargo.toml

@@ -22,7 +22,7 @@ embedded-hal-0-2 = { package = "embedded-hal", version = "0.2.4", features = ["u
 embedded-hal = "1"
 switch-hal = "0.4.0"
 nb = "0.1.1"
-riot-sys = "0.7.10"
+riot-sys = "0.7.13"
 num-traits = { version = "0.2", default-features = false }
 mutex-trait = "0.2"
 

src/led.rs

@@ -7,13 +7,57 @@ use core::convert::Infallible;
 /// The preferred interface for turning a LED on and off is [switch_hal::OutputSwitch].
 ///
 /// LEDs are accessible safely; any not implemented on a board are silently ignored.
+#[derive(Debug)]
 pub struct LED<const I: u8>(());
 
+/// The indicated LED is not present on the current board.
+#[derive(Debug)]
+pub struct LedNotPresent;
+
 impl<const I: u8> LED<I> {
+    #[deprecated(
+        note = "Use new_unchecked() to retain the behavior this function has always had; future versions of `.new()` will panic when used with a board that does not have that LED.",
+        since = "0.9.1"
+    )]
     pub const fn new() -> Self {
+        Self::new_unchecked()
+    }
+
+    /// Accesses the LED numbered `I`.
+    ///
+    /// It is not an error if this board does not have a LED with that number; the resulting struct
+    /// will be available but its methods have no effect.
+    pub const fn new_unchecked() -> Self {
         assert!(I < 8, "RIOT only defines LED0..7");
         Self(())
     }
+
+    /// Accesses the LED numbered `I`.
+    ///
+    /// An LED is returned if present on the board, which is known at build time.
+    pub const fn new_checked() -> Result<Self, LedNotPresent> {
+        if Self::is_present() {
+            Ok(Self(()))
+        } else {
+            Err(LedNotPresent)
+        }
+    }
+
+    const fn is_present() -> bool {
+        unsafe {
+            match I {
+                0 => riot_sys::macro_LED0_IS_PRESENT() != -1,
+                1 => riot_sys::macro_LED1_IS_PRESENT() != -1,
+                2 => riot_sys::macro_LED2_IS_PRESENT() != -1,
+                3 => riot_sys::macro_LED3_IS_PRESENT() != -1,
+                4 => riot_sys::macro_LED4_IS_PRESENT() != -1,
+                5 => riot_sys::macro_LED5_IS_PRESENT() != -1,
+                6 => riot_sys::macro_LED6_IS_PRESENT() != -1,
+                7 => riot_sys::macro_LED7_IS_PRESENT() != -1,
+                _ => panic!("RIOT only defines LED0..7"),
+            }
+        }
+    }
 }
 
 impl<const I: u8> switch_hal::OutputSwitch for LED<I> {

tests/led/src/lib.rs

@@ -6,14 +6,17 @@ use riot_wrappers::riot_main;
 riot_main!(main);
 
 fn main() {
-    let mut led0 = LED::<0>::new();
-    let mut led1 = LED::<1>::new();
-    let mut led2 = LED::<2>::new();
-    let mut led3 = LED::<3>::new();
-    let mut led4 = LED::<4>::new();
-    let mut led5 = LED::<5>::new();
-    let mut led6 = LED::<6>::new();
-    let mut led7 = LED::<7>::new();
+    // Using the `unchecked` methods because the loop rotates the blinking speeds through all LEDs
+    // anyway -- so every speed will be on every LED, and that's easier to express if the number of
+    // considered LEDs is constant.
+    let mut led0 = LED::<0>::new_unchecked();
+    let mut led1 = LED::<1>::new_unchecked();
+    let mut led2 = LED::<2>::new_unchecked();
+    let mut led3 = LED::<3>::new_unchecked();
+    let mut led4 = LED::<4>::new_unchecked();
+    let mut led5 = LED::<5>::new_unchecked();
+    let mut led6 = LED::<6>::new_unchecked();
+    let mut led7 = LED::<7>::new_unchecked();
     let mut leds: [&mut dyn switch_hal::ToggleableOutputSwitch<Error = _>; 8] = [
         &mut led0, &mut led1, &mut led2, &mut led3, &mut led4, &mut led5, &mut led6, &mut led7,
     ];