tests: Add i2c test

tests/i2c/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "riot-wrappers-test-i2c"
+version = "0.1.0"
+authors = ["Christian Amsüss <[email protected]>"]
+edition = "2021"
+publish = false
+
+[lib]
+crate-type = ["staticlib"]
+
+[profile.release]
+panic = "abort"
+
+[dependencies]
+riot-wrappers = { version = "*", features = [ "set_panic_handler", "panic_handler_format" ] }
+riot-sys = "*"
+embedded-hal = "0.2"

tests/i2c/Makefile

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+# name of your application
+APPLICATION = riot-wrappers-test-i2c
+APPLICATION_RUST_MODULE = riot_wrappers_test_i2c
+BASELIBS += $(APPLICATION_RUST_MODULE).module
+FEATURES_REQUIRED += rust_target
+FEATURES_REQUIRED += periph_i2c
+
+include $(RIOTBASE)/Makefile.include

tests/i2c/src/lib.rs

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+//! This is a primitive I2C scanner, and should thus report *something* interesting if any I2C
+//! device is connected. (And reading should be safe on any device / bus).
+#![no_std]
+
+use embedded_hal::blocking::i2c::Read;
+
+use riot_wrappers::println;
+use riot_wrappers::riot_main;
+
+riot_main!(main);
+
+fn main() {
+    let mut i2c = riot_wrappers::i2c::I2CDevice::new(0); // FIXME from_number?
+
+    let mut buf = [0];
+
+    loop {
+        for i in 0..=127 {
+            match i2c.read(i, &mut buf) {
+                Ok(()) => println!("From {i}, read bytes: {:?}", &buf),
+                Err(e) => println!("From {i}, error {e:?}"),
+            }
+        }
+    }
+}