Struct Spidev

pub struct Spidev { /* private fields */ }

Provide high-level access to Linux Spidev Driver

Implementations

impl Spidev

pub fn new(devfile: File) -> Self

Wrap an already opened File for use as an spidev

pub fn open<P: AsRef<Path>>(path: P) -> Result<Spidev>

Open the spidev device with the provided path

Typically, the path will be something like "/dev/spidev0.0" where the first number if the bus and the second number is the chip select on that bus for the device being targeted.

Examples found in repository

examples/spidev-hello.rs (line 6)

fn main() {
    let mut spidev = Spidev::open("/dev/spidev0.0").unwrap();
    let wrote = spidev.write(&[0xAA, 0x00, 0x01, 0x02, 0x04]).unwrap();

    let mut buf: [u8; 10] = [0; 10];
    let read = spidev.read(&mut buf).unwrap(); // read 10
    println!("Wrote: {}, Read: {}, Data: {:?}", wrote, read, buf);
}

examples/spidev-bidir.rs (line 6)

fn main() {
    let mut spidev = Spidev::open("/dev/spidev0.0").unwrap();
    let options = SpidevOptions::new()
        .bits_per_word(8)
        .max_speed_hz(5000)
        .lsb_first(false)
        .mode(SpiModeFlags::SPI_MODE_0)
        .build();
    spidev.configure(&options).unwrap();

    println!("===== Single transfer =========");
    let tx_buf = [0xaa, 0xbb, 0xcc, 0xdd, 0xee];
    let mut rx_buf = [0; 5];
    let mut transfer = SpidevTransfer::read_write(&tx_buf, &mut rx_buf);
    println!("{:?}", spidev.transfer(&mut transfer));

    println!("===== Multi Transfer =========");
    let mut rx_buf1 = [0; 10];
    let tx_buf2 = [0x00, 0x01, 0x02, 0x03];
    let delay_usecs = 10;
    let tx_buf3 = [0xff, 0xfe, 0xfd];
    let mut rx_buf3 = [0; 3];
    let result = {
        let mut transfers = vec![
            SpidevTransfer::read(&mut rx_buf1),
            SpidevTransfer::write(&tx_buf2),
            SpidevTransfer::delay(delay_usecs),
            SpidevTransfer::read_write(&tx_buf3, &mut rx_buf3),
        ];
        spidev.transfer_multiple(&mut transfers)
    };
    match result {
        Ok(_) => {
            println!("Read {:?}", rx_buf1);
            println!("Wrote {:?}", tx_buf2);
            println!("Delayed by {} microseconds", delay_usecs);
            println!("Wrote {:?} and read {:?}", tx_buf3, rx_buf3);
        }
        Err(err) => println!("{:?}", err),
    }
}

pub fn inner(&self) -> &File

Get a reference to the underlying File object

pub fn into_inner(self) -> File

Consume the object and get the underlying File object

pub fn configure(&mut self, options: &SpidevOptions) -> Result<()>

Write the provided configuration to this device

Examples found in repository

examples/spidev-bidir.rs (line 13)

fn main() {
    let mut spidev = Spidev::open("/dev/spidev0.0").unwrap();
    let options = SpidevOptions::new()
        .bits_per_word(8)
        .max_speed_hz(5000)
        .lsb_first(false)
        .mode(SpiModeFlags::SPI_MODE_0)
        .build();
    spidev.configure(&options).unwrap();

    println!("===== Single transfer =========");
    let tx_buf = [0xaa, 0xbb, 0xcc, 0xdd, 0xee];
    let mut rx_buf = [0; 5];
    let mut transfer = SpidevTransfer::read_write(&tx_buf, &mut rx_buf);
    println!("{:?}", spidev.transfer(&mut transfer));

    println!("===== Multi Transfer =========");
    let mut rx_buf1 = [0; 10];
    let tx_buf2 = [0x00, 0x01, 0x02, 0x03];
    let delay_usecs = 10;
    let tx_buf3 = [0xff, 0xfe, 0xfd];
    let mut rx_buf3 = [0; 3];
    let result = {
        let mut transfers = vec![
            SpidevTransfer::read(&mut rx_buf1),
            SpidevTransfer::write(&tx_buf2),
            SpidevTransfer::delay(delay_usecs),
            SpidevTransfer::read_write(&tx_buf3, &mut rx_buf3),
        ];
        spidev.transfer_multiple(&mut transfers)
    };
    match result {
        Ok(_) => {
            println!("Read {:?}", rx_buf1);
            println!("Wrote {:?}", tx_buf2);
            println!("Delayed by {} microseconds", delay_usecs);
            println!("Wrote {:?} and read {:?}", tx_buf3, rx_buf3);
        }
        Err(err) => println!("{:?}", err),
    }
}

pub fn query_configuration(&self) -> Result<SpidevOptions>

Read the current configuration from this device

pub fn transfer(&self, transfer: &mut SpidevTransfer<'_, '_>) -> Result<()>

Perform a single transfer

Examples found in repository

examples/spidev-bidir.rs (line 19)

fn main() {
    let mut spidev = Spidev::open("/dev/spidev0.0").unwrap();
    let options = SpidevOptions::new()
        .bits_per_word(8)
        .max_speed_hz(5000)
        .lsb_first(false)
        .mode(SpiModeFlags::SPI_MODE_0)
        .build();
    spidev.configure(&options).unwrap();

    println!("===== Single transfer =========");
    let tx_buf = [0xaa, 0xbb, 0xcc, 0xdd, 0xee];
    let mut rx_buf = [0; 5];
    let mut transfer = SpidevTransfer::read_write(&tx_buf, &mut rx_buf);
    println!("{:?}", spidev.transfer(&mut transfer));

    println!("===== Multi Transfer =========");
    let mut rx_buf1 = [0; 10];
    let tx_buf2 = [0x00, 0x01, 0x02, 0x03];
    let delay_usecs = 10;
    let tx_buf3 = [0xff, 0xfe, 0xfd];
    let mut rx_buf3 = [0; 3];
    let result = {
        let mut transfers = vec![
            SpidevTransfer::read(&mut rx_buf1),
            SpidevTransfer::write(&tx_buf2),
            SpidevTransfer::delay(delay_usecs),
            SpidevTransfer::read_write(&tx_buf3, &mut rx_buf3),
        ];
        spidev.transfer_multiple(&mut transfers)
    };
    match result {
        Ok(_) => {
            println!("Read {:?}", rx_buf1);
            println!("Wrote {:?}", tx_buf2);
            println!("Delayed by {} microseconds", delay_usecs);
            println!("Wrote {:?} and read {:?}", tx_buf3, rx_buf3);
        }
        Err(err) => println!("{:?}", err),
    }
}

pub fn transfer_multiple( &self, transfers: &mut [SpidevTransfer<'_, '_>], ) -> Result<()>

Perform multiple transfers in a single system call to the kernel

Chaining together multiple requests like this can reduce latency and be used for conveniently and efficient implementing some protocols without extra round trips back to userspace.

Examples found in repository

examples/spidev-bidir.rs (line 34)

fn main() {
    let mut spidev = Spidev::open("/dev/spidev0.0").unwrap();
    let options = SpidevOptions::new()
        .bits_per_word(8)
        .max_speed_hz(5000)
        .lsb_first(false)
        .mode(SpiModeFlags::SPI_MODE_0)
        .build();
    spidev.configure(&options).unwrap();

    println!("===== Single transfer =========");
    let tx_buf = [0xaa, 0xbb, 0xcc, 0xdd, 0xee];
    let mut rx_buf = [0; 5];
    let mut transfer = SpidevTransfer::read_write(&tx_buf, &mut rx_buf);
    println!("{:?}", spidev.transfer(&mut transfer));

    println!("===== Multi Transfer =========");
    let mut rx_buf1 = [0; 10];
    let tx_buf2 = [0x00, 0x01, 0x02, 0x03];
    let delay_usecs = 10;
    let tx_buf3 = [0xff, 0xfe, 0xfd];
    let mut rx_buf3 = [0; 3];
    let result = {
        let mut transfers = vec![
            SpidevTransfer::read(&mut rx_buf1),
            SpidevTransfer::write(&tx_buf2),
            SpidevTransfer::delay(delay_usecs),
            SpidevTransfer::read_write(&tx_buf3, &mut rx_buf3),
        ];
        spidev.transfer_multiple(&mut transfers)
    };
    match result {
        Ok(_) => {
            println!("Read {:?}", rx_buf1);
            println!("Wrote {:?}", tx_buf2);
            println!("Delayed by {} microseconds", delay_usecs);
            println!("Wrote {:?} and read {:?}", tx_buf3, rx_buf3);
        }
        Err(err) => println!("{:?}", err),
    }
}

Trait Implementations

impl AsRawFd for Spidev

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl Debug for Spidev

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Read for Spidev

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl Write for Spidev

fn write(&mut self, buf: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.