embassy/embassy-embedded-hal/src/adapter.rs

//! Adapters between embedded-hal traits.

use embassy_futures::yield_now;
use embedded_hal_02::{blocking, serial};

/// Wrapper that implements async traits using blocking implementations.
///
/// This allows driver writers to depend on the async traits while still supporting embedded-hal peripheral implementations.
///
/// BlockingAsync will implement any async trait that maps to embedded-hal traits implemented for the wrapped driver.
///
/// Driver users are then free to choose which implementation that is available to them.
pub struct BlockingAsync<T> {
    wrapped: T,
}

impl<T> BlockingAsync<T> {
    /// Create a new instance of a wrapper for a given peripheral.
    pub fn new(wrapped: T) -> Self {
        Self { wrapped }
    }
}

//
// I2C implementations
//
impl<T, E> embedded_hal_1::i2c::ErrorType for BlockingAsync<T>
where
    E: embedded_hal_1::i2c::Error + 'static,
    T: blocking::i2c::WriteRead<Error = E> + blocking::i2c::Read<Error = E> + blocking::i2c::Write<Error = E>,
{
    type Error = E;
}

impl<T, E> embedded_hal_async::i2c::I2c for BlockingAsync<T>
where
    E: embedded_hal_1::i2c::Error + 'static,
    T: blocking::i2c::WriteRead<Error = E> + blocking::i2c::Read<Error = E> + blocking::i2c::Write<Error = E>,
{
    async fn read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Self::Error> {
        self.wrapped.read(address, read)
    }

    async fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Self::Error> {
        self.wrapped.write(address, write)
    }

    async fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
        self.wrapped.write_read(address, write, read)
    }

    async fn transaction(
        &mut self,
        address: u8,
        operations: &mut [embedded_hal_1::i2c::Operation<'_>],
    ) -> Result<(), Self::Error> {
        let _ = address;
        let _ = operations;
        todo!()
    }
}

//
// SPI implementatinos
//

impl<T, E> embedded_hal_async::spi::ErrorType for BlockingAsync<T>
where
    E: embedded_hal_1::spi::Error,
    T: blocking::spi::Transfer<u8, Error = E> + blocking::spi::Write<u8, Error = E>,
{
    type Error = E;
}

impl<T, E> embedded_hal_async::spi::SpiBus<u8> for BlockingAsync<T>
where
    E: embedded_hal_1::spi::Error + 'static,
    T: blocking::spi::Transfer<u8, Error = E> + blocking::spi::Write<u8, Error = E>,
{
    async fn transfer<'a>(&'a mut self, read: &'a mut [u8], write: &'a [u8]) -> Result<(), Self::Error> {
        // Ensure we write the expected bytes
        for i in 0..core::cmp::min(read.len(), write.len()) {
            read[i] = write[i].clone();
        }
        self.wrapped.transfer(read)?;
        Ok(())
    }

    async fn transfer_in_place<'a>(&'a mut self, _: &'a mut [u8]) -> Result<(), Self::Error> {
        todo!()
    }
}

impl<T, E> embedded_hal_async::spi::SpiBusFlush for BlockingAsync<T>
where
    E: embedded_hal_1::spi::Error + 'static,
    T: blocking::spi::Transfer<u8, Error = E> + blocking::spi::Write<u8, Error = E>,
{
    async fn flush(&mut self) -> Result<(), Self::Error> {
        Ok(())
    }
}

impl<T, E> embedded_hal_async::spi::SpiBusWrite<u8> for BlockingAsync<T>
where
    E: embedded_hal_1::spi::Error + 'static,
    T: blocking::spi::Transfer<u8, Error = E> + blocking::spi::Write<u8, Error = E>,
{
    async fn write(&mut self, data: &[u8]) -> Result<(), Self::Error> {
        self.wrapped.write(data)?;
        Ok(())
    }
}

impl<T, E> embedded_hal_async::spi::SpiBusRead<u8> for BlockingAsync<T>
where
    E: embedded_hal_1::spi::Error + 'static,
    T: blocking::spi::Transfer<u8, Error = E> + blocking::spi::Write<u8, Error = E>,
{
    async fn read(&mut self, data: &mut [u8]) -> Result<(), Self::Error> {
        self.wrapped.transfer(data)?;
        Ok(())
    }
}

// Uart implementatinos
impl<T, E> embedded_hal_1::serial::ErrorType for BlockingAsync<T>
where
    T: serial::Read<u8, Error = E>,
    E: embedded_hal_1::serial::Error + 'static,
{
    type Error = E;
}

/// NOR flash wrapper
use embedded_storage::nor_flash::{ErrorType, NorFlash, ReadNorFlash};
use embedded_storage_async::nor_flash::{NorFlash as AsyncNorFlash, ReadNorFlash as AsyncReadNorFlash};

impl<T> ErrorType for BlockingAsync<T>
where
    T: ErrorType,
{
    type Error = T::Error;
}

impl<T> AsyncNorFlash for BlockingAsync<T>
where
    T: NorFlash,
{
    const WRITE_SIZE: usize = <T as NorFlash>::WRITE_SIZE;
    const ERASE_SIZE: usize = <T as NorFlash>::ERASE_SIZE;

    async fn write(&mut self, offset: u32, data: &[u8]) -> Result<(), Self::Error> {
        self.wrapped.write(offset, data)?;
        yield_now().await;
        Ok(())
    }

    async fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
        for from in (from..to).step_by(T::ERASE_SIZE) {
            let to = core::cmp::min(from + T::ERASE_SIZE as u32, to);
            self.wrapped.erase(from, to)?;
            yield_now().await;
        }
        Ok(())
    }
}

impl<T> AsyncReadNorFlash for BlockingAsync<T>
where
    T: ReadNorFlash,
{
    const READ_SIZE: usize = <T as ReadNorFlash>::READ_SIZE;
    async fn read(&mut self, address: u32, data: &mut [u8]) -> Result<(), Self::Error> {
        self.wrapped.read(address, data)
    }

    fn capacity(&self) -> usize {
        self.wrapped.capacity()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    extern crate std;

    #[derive(Default)]
    struct FakeFlash(Vec<(u32, u32)>);

    impl embedded_storage::nor_flash::ErrorType for FakeFlash {
        type Error = std::convert::Infallible;
    }

    impl embedded_storage::nor_flash::ReadNorFlash for FakeFlash {
        const READ_SIZE: usize = 1;

        fn read(&mut self, _offset: u32, _bytes: &mut [u8]) -> Result<(), Self::Error> {
            unimplemented!()
        }

        fn capacity(&self) -> usize {
            unimplemented!()
        }
    }

    impl embedded_storage::nor_flash::NorFlash for FakeFlash {
        const WRITE_SIZE: usize = 4;
        const ERASE_SIZE: usize = 128;

        fn write(&mut self, _offset: u32, _bytes: &[u8]) -> Result<(), Self::Error> {
            unimplemented!()
        }

        fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
            self.0.push((from, to));
            Ok(())
        }
    }

    #[futures_test::test]
    async fn can_erase() {
        let fake = FakeFlash::default();
        let mut yielding = BlockingAsync::new(fake);

        yielding.erase(0, 256).await.unwrap();

        let fake = yielding.wrapped;
        assert_eq!(2, fake.0.len());
        assert_eq!((0, 128), fake.0[0]);
        assert_eq!((128, 256), fake.0[1]);
    }

    #[futures_test::test]
    async fn can_erase_wrong_erase_size() {
        let fake = FakeFlash::default();
        let mut yielding = BlockingAsync::new(fake);

        yielding.erase(0, 257).await.unwrap();

        let fake = yielding.wrapped;
        assert_eq!(3, fake.0.len());
        assert_eq!((0, 128), fake.0[0]);
        assert_eq!((128, 256), fake.0[1]);
        assert_eq!((256, 257), fake.0[2]);
    }
}