embassy/examples/std/src/serial_port.rs
2021-11-26 04:12:14 +01:00

69 lines
2.1 KiB
Rust

use nix::errno::Errno;
use nix::fcntl::OFlag;
use nix::sys::termios;
use std::io;
use std::os::unix::io::{AsRawFd, RawFd};
pub struct SerialPort {
fd: RawFd,
}
impl SerialPort {
pub fn new<P: ?Sized + nix::NixPath>(
path: &P,
baudrate: termios::BaudRate,
) -> io::Result<Self> {
let fd = nix::fcntl::open(
path,
OFlag::O_RDWR | OFlag::O_NOCTTY | OFlag::O_NONBLOCK,
nix::sys::stat::Mode::empty(),
)
.map_err(to_io_error)?;
let mut cfg = termios::tcgetattr(fd).map_err(to_io_error)?;
cfg.input_flags = termios::InputFlags::empty();
cfg.output_flags = termios::OutputFlags::empty();
cfg.control_flags = termios::ControlFlags::empty();
cfg.local_flags = termios::LocalFlags::empty();
termios::cfmakeraw(&mut cfg);
cfg.input_flags |= termios::InputFlags::IGNBRK;
cfg.control_flags |= termios::ControlFlags::CREAD;
//cfg.control_flags |= termios::ControlFlags::CRTSCTS;
termios::cfsetospeed(&mut cfg, baudrate).map_err(to_io_error)?;
termios::cfsetispeed(&mut cfg, baudrate).map_err(to_io_error)?;
termios::cfsetspeed(&mut cfg, baudrate).map_err(to_io_error)?;
// Set VMIN = 1 to block until at least one character is received.
cfg.control_chars[termios::SpecialCharacterIndices::VMIN as usize] = 1;
termios::tcsetattr(fd, termios::SetArg::TCSANOW, &cfg).map_err(to_io_error)?;
termios::tcflush(fd, termios::FlushArg::TCIOFLUSH).map_err(to_io_error)?;
Ok(Self { fd })
}
}
impl AsRawFd for SerialPort {
fn as_raw_fd(&self) -> RawFd {
self.fd
}
}
impl io::Read for SerialPort {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
nix::unistd::read(self.fd, buf).map_err(to_io_error)
}
}
impl io::Write for SerialPort {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
nix::unistd::write(self.fd, buf).map_err(to_io_error)
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
fn to_io_error(e: Errno) -> io::Error {
e.into()
}