Merge #1025

1025: Implement I2C timeouts, second attempt r=Dirbaio a=chemicstry

This is an alterrnative to #1022 as discussed there.

Timeouts are implemented using suggested `check_timeout: impl Fn() -> Result<(), Error>` function, which does not depend on `embassy-time` by default and is a noop for regular I2C.

This also adds `time` feature like in `embassy-nrf` to enable `embassy-time` dependencies. While at it, I also gated some other peripherals that depend on `embassy-time`, notably `usb` and (partially) `subghz`.

`TimeoutI2c` is currently only implemented for i2cv1, because i2cv2 has additional complications:
- Async methods still use a lot of busy waiting code in between DMA transfers, so simple `with_timeout()` will not work and it will have to use both types of timeouts. It could probably be rewritten to replace busy waits with IRQs, but that's outside the scope of this PR.
- I2C definition `I2c<'d, T, TXDMA, RXDMA>` is different from i2cv1 `I2c<'d, T>` making it hard to share single `TimeoutI2c` wrapper. A couple of options here:
  - Duplicate `TimeoutI2c` code
  - Add dummy `TXDMA`, `RXDMA` types to i2cv1 considering that in the future it should also support DMA

Co-authored-by: chemicstry <[email protected]>

2 files changed, 89 insertions, 0 deletions

diff --git a/examples/stm32f4/src/bin/i2c.rs b/examples/stm32f4/src/bin/i2c.rs
new file mode 100644
index 000000000..6e51c211d
--- /dev/null
+++ b/examples/stm32f4/src/bin/i2c.rs
@@ -0,0 +1,45 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::dma::NoDma;
+use embassy_stm32::i2c::{Error, I2c, TimeoutI2c};
+use embassy_stm32::interrupt;
+use embassy_stm32::time::Hertz;
+use embassy_time::Duration;
+use {defmt_rtt as _, panic_probe as _};
+
+const ADDRESS: u8 = 0x5F;
+const WHOAMI: u8 = 0x0F;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+    let p = embassy_stm32::init(Default::default());
+
+    let irq = interrupt::take!(I2C2_EV);
+    let mut i2c = I2c::new(
+        p.I2C2,
+        p.PB10,
+        p.PB11,
+        irq,
+        NoDma,
+        NoDma,
+        Hertz(100_000),
+        Default::default(),
+    );
+
+    // I2C bus can freeze if SCL line is shorted or due to a broken device that clock stretches for too long.
+    // TimeoutI2c allows recovering from such errors by throwing `Error::Timeout` after a given delay.
+    let mut timeout_i2c = TimeoutI2c::new(&mut i2c, Duration::from_millis(1000));
+
+    let mut data = [0u8; 1];
+
+    match timeout_i2c.blocking_write_read(ADDRESS, &[WHOAMI], &mut data) {
+        Ok(()) => info!("Whoami: {}", data[0]),
+        Err(Error::Timeout) => error!("Operation timed out"),
+        Err(e) => error!("I2c Error: {:?}", e),
+    }
+}
diff --git a/examples/stm32h7/src/bin/i2c.rs b/examples/stm32h7/src/bin/i2c.rs
new file mode 100644
index 000000000..d44319ae6
--- /dev/null
+++ b/examples/stm32h7/src/bin/i2c.rs
@@ -0,0 +1,44 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::i2c::{Error, I2c, TimeoutI2c};
+use embassy_stm32::interrupt;
+use embassy_stm32::time::Hertz;
+use embassy_time::Duration;
+use {defmt_rtt as _, panic_probe as _};
+
+const ADDRESS: u8 = 0x5F;
+const WHOAMI: u8 = 0x0F;
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+    let p = embassy_stm32::init(Default::default());
+
+    let irq = interrupt::take!(I2C2_EV);
+    let mut i2c = I2c::new(
+        p.I2C2,
+        p.PB10,
+        p.PB11,
+        irq,
+        p.DMA1_CH4,
+        p.DMA1_CH5,
+        Hertz(100_000),
+        Default::default(),
+    );
+
+    // I2C bus can freeze if SCL line is shorted or due to a broken device that clock stretches for too long.
+    // TimeoutI2c allows recovering from such errors by throwing `Error::Timeout` after a given delay.
+    let mut timeout_i2c = TimeoutI2c::new(&mut i2c, Duration::from_millis(1000));
+
+    let mut data = [0u8; 1];
+
+    match timeout_i2c.blocking_write_read(ADDRESS, &[WHOAMI], &mut data) {
+        Ok(()) => info!("Whoami: {}", data[0]),
+        Err(Error::Timeout) => error!("Operation timed out"),
+        Err(e) => error!("I2c Error: {:?}", e),
+    }
+}