Merge #35

35: Add transactional SPI r=ryankurte a=ryankurte

Implementation of transactional SPI

- replaces #33
- blocked on:
  - ~rust-embedded/embedded-hal#191
  - ~#34

~Important: remove patch and bump hal version before merging~

Co-authored-by: ryan <ryan@kurte.nz>
Co-authored-by: Ryan <ryankurte@users.noreply.github.com>

Author: bors[bot]

Cargo.toml

@@ -1,12 +1,16 @@
 [package]
-authors = ["Jorge Aparicio <jorge@japaric.io>"]
+authors = [
+    "The Embedded Linux Team <embedded-linux@teams.rust-embedded.org>",
+    "Jorge Aparicio <jorge@japaric.io>"
+]
 categories = ["embedded", "hardware-support"]
 description = "Implementation of the `embedded-hal` traits for Linux devices"
 keywords = ["Linux", "hal"]
 license = "MIT OR Apache-2.0"
 name = "linux-embedded-hal"
-repository = "https://github.com/japaric/linux-embedded-hal"
+repository = "https://github.com/rust-embedded/linux-embedded-hal"
 version = "0.3.0"
+edition = "2018"
 
 [features]
 gpio_sysfs = ["sysfs_gpio"]
@@ -32,3 +36,4 @@ openpty = "0.1.0"
 # we don't need the `Error` implementation
 default-features = false
 version = "0.2.2"
+

src/cdev_pin.rs

@@ -15,7 +15,7 @@ impl CdevPin {
     }
 }
 
-impl hal::digital::OutputPin for CdevPin {
+impl embedded_hal::digital::OutputPin for CdevPin {
     type Error = gpio_cdev::errors::Error;
 
     fn try_set_low(&mut self) -> Result<(), Self::Error> {
@@ -27,7 +27,7 @@ impl hal::digital::OutputPin for CdevPin {
     }
 }
 
-impl hal::digital::InputPin for CdevPin {
+impl embedded_hal::digital::InputPin for CdevPin {
     type Error = gpio_cdev::errors::Error;
 
     fn try_is_high(&self) -> Result<bool, Self::Error> {

src/lib.rs

@@ -12,20 +12,19 @@
 
 #![deny(missing_docs)]
 
-extern crate cast;
-extern crate core;
-extern crate embedded_hal as hal;
-pub extern crate i2cdev;
-pub extern crate nb;
-pub extern crate serial_core;
-pub extern crate serial_unix;
-pub extern crate spidev;
+use cast;
+pub use i2cdev;
+pub use nb;
+pub use serial_core;
+pub use serial_unix;
+pub use spidev;
 
 #[cfg(feature = "gpio_sysfs")]
-pub extern crate sysfs_gpio;
+pub use sysfs_gpio;
 
 #[cfg(feature = "gpio_cdev")]
-pub extern crate gpio_cdev;
+pub use gpio_cdev;
+
 
 use core::convert::Infallible;
 use std::io::{self, Write};
@@ -34,7 +33,7 @@ use std::time::Duration;
 use std::{ops, thread};
 
 use cast::{u32, u64};
-use hal::blocking::i2c::Operation as I2cOperation;
+use embedded_hal::blocking::i2c::Operation as I2cOperation;
 use i2cdev::core::{I2CDevice, I2CMessage, I2CTransfer};
 use i2cdev::linux::LinuxI2CMessage;
 use spidev::SpidevTransfer;
@@ -63,7 +62,7 @@ pub use sysfs_pin::SysfsPin;
 /// Empty struct that provides delay functionality on top of `thread::sleep`
 pub struct Delay;
 
-impl hal::blocking::delay::DelayUs<u8> for Delay {
+impl embedded_hal::blocking::delay::DelayUs<u8> for Delay {
     type Error = Infallible;
 
     fn try_delay_us(&mut self, n: u8) -> Result<(), Self::Error> {
@@ -72,7 +71,7 @@ impl hal::blocking::delay::DelayUs<u8> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayUs<u16> for Delay {
+impl embedded_hal::blocking::delay::DelayUs<u16> for Delay {
     type Error = Infallible;
 
     fn try_delay_us(&mut self, n: u16) -> Result<(), Self::Error> {
@@ -81,7 +80,7 @@ impl hal::blocking::delay::DelayUs<u16> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayUs<u32> for Delay {
+impl embedded_hal::blocking::delay::DelayUs<u32> for Delay {
     type Error = Infallible;
 
     fn try_delay_us(&mut self, n: u32) -> Result<(), Self::Error> {
@@ -93,7 +92,7 @@ impl hal::blocking::delay::DelayUs<u32> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayUs<u64> for Delay {
+impl embedded_hal::blocking::delay::DelayUs<u64> for Delay {
     type Error = Infallible;
 
     fn try_delay_us(&mut self, n: u64) -> Result<(), Self::Error> {
@@ -105,7 +104,7 @@ impl hal::blocking::delay::DelayUs<u64> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayMs<u8> for Delay {
+impl embedded_hal::blocking::delay::DelayMs<u8> for Delay {
     type Error = Infallible;
 
     fn try_delay_ms(&mut self, n: u8) -> Result<(), Self::Error> {
@@ -114,7 +113,7 @@ impl hal::blocking::delay::DelayMs<u8> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayMs<u16> for Delay {
+impl embedded_hal::blocking::delay::DelayMs<u16> for Delay {
     type Error = Infallible;
 
     fn try_delay_ms(&mut self, n: u16) -> Result<(), Self::Error> {
@@ -123,7 +122,7 @@ impl hal::blocking::delay::DelayMs<u16> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayMs<u32> for Delay {
+impl embedded_hal::blocking::delay::DelayMs<u32> for Delay {
     type Error = Infallible;
 
     fn try_delay_ms(&mut self, n: u32) -> Result<(), Self::Error> {
@@ -132,7 +131,7 @@ impl hal::blocking::delay::DelayMs<u32> for Delay {
     }
 }
 
-impl hal::blocking::delay::DelayMs<u64> for Delay {
+impl embedded_hal::blocking::delay::DelayMs<u64> for Delay {
     type Error = Infallible;
 
     fn try_delay_ms(&mut self, n: u64) -> Result<(), Self::Error> {
@@ -175,7 +174,7 @@ impl I2cdev {
     }
 }
 
-impl hal::blocking::i2c::Read for I2cdev {
+impl embedded_hal::blocking::i2c::Read for I2cdev {
     type Error = i2cdev::linux::LinuxI2CError;
 
     fn try_read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Self::Error> {
@@ -184,7 +183,7 @@ impl hal::blocking::i2c::Read for I2cdev {
     }
 }
 
-impl hal::blocking::i2c::Write for I2cdev {
+impl embedded_hal::blocking::i2c::Write for I2cdev {
     type Error = i2cdev::linux::LinuxI2CError;
 
     fn try_write(&mut self, address: u8, bytes: &[u8]) -> Result<(), Self::Error> {
@@ -193,7 +192,7 @@ impl hal::blocking::i2c::Write for I2cdev {
     }
 }
 
-impl hal::blocking::i2c::WriteRead for I2cdev {
+impl embedded_hal::blocking::i2c::WriteRead for I2cdev {
     type Error = i2cdev::linux::LinuxI2CError;
 
     fn try_write_read(
@@ -203,12 +202,15 @@ impl hal::blocking::i2c::WriteRead for I2cdev {
         buffer: &mut [u8],
     ) -> Result<(), Self::Error> {
         self.set_address(address)?;
-        let mut messages = [LinuxI2CMessage::write(bytes), LinuxI2CMessage::read(buffer)];
+        let mut messages = [
+            LinuxI2CMessage::write(bytes),
+            LinuxI2CMessage::read(buffer),
+        ];
         self.inner.transfer(&mut messages).map(drop)
     }
 }
 
-impl hal::blocking::i2c::Transactional for I2cdev {
+impl embedded_hal::blocking::i2c::Transactional for I2cdev {
     type Error = i2cdev::linux::LinuxI2CError;
 
     fn try_exec(&mut self, address: u8, operations: &mut [I2cOperation]) -> Result<(), Self::Error>
@@ -259,7 +261,7 @@ impl Spidev {
     }
 }
 
-impl hal::blocking::spi::Transfer<u8> for Spidev {
+impl embedded_hal::blocking::spi::Transfer<u8> for Spidev {
     type Error = io::Error;
 
     fn try_transfer<'b>(&mut self, buffer: &'b mut [u8]) -> io::Result<&'b [u8]> {
@@ -270,14 +272,44 @@ impl hal::blocking::spi::Transfer<u8> for Spidev {
     }
 }
 
-impl hal::blocking::spi::Write<u8> for Spidev {
+impl embedded_hal::blocking::spi::Write<u8> for Spidev {
     type Error = io::Error;
 
     fn try_write(&mut self, buffer: &[u8]) -> io::Result<()> {
         self.0.write_all(buffer)
     }
 }
 
+pub use embedded_hal::blocking::spi::{Operation as SpiOperation};
+
+/// Transactional implementation batches SPI operations into a single transaction
+impl embedded_hal::blocking::spi::Transactional<u8> for Spidev {
+    type Error = io::Error;
+
+    fn try_exec<'a>(&mut self, operations: &mut [SpiOperation<'a, u8>]) -> Result<(), Self::Error> {
+
+        // Map types from generic to linux objects
+        let mut messages: Vec<_> = operations.iter_mut().map(|a| {
+            match a {
+                SpiOperation::Write(w) => SpidevTransfer::write(w),
+                SpiOperation::Transfer(r) => {
+                    // Clone read to write pointer
+                    // SPIdev is okay with having w == r but this is tricky to achieve in safe rust
+                    let w = unsafe {
+                        let p = r.as_ptr();
+                        std::slice::from_raw_parts(p, r.len())
+                    };
+
+                    SpidevTransfer::read_write(w, r)
+                },
+            }
+        }).collect();
+
+        // Execute transfer
+        self.0.transfer_multiple(&mut messages)
+    }
+}
+
 impl ops::Deref for Spidev {
     type Target = spidev::Spidev;
 

src/serial.rs

@@ -5,7 +5,6 @@ use std::path::Path;
 
 use nb;
 
-use hal;
 use serial_core;
 use serial_unix::TTYPort;
 
@@ -30,7 +29,7 @@ fn translate_io_errors(err: std::io::Error) -> nb::Error<IoErrorKind> {
     }
 }
 
-impl hal::serial::Read<u8> for Serial {
+impl embedded_hal::serial::Read<u8> for Serial {
     type Error = IoErrorKind;
 
     fn try_read(&mut self) -> nb::Result<u8, Self::Error> {
@@ -44,7 +43,7 @@ impl hal::serial::Read<u8> for Serial {
     }
 }
 
-impl hal::serial::Write<u8> for Serial {
+impl embedded_hal::serial::Write<u8> for Serial {
     type Error = IoErrorKind;
 
     fn try_write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
@@ -61,7 +60,7 @@ impl hal::serial::Write<u8> for Serial {
 mod test {
     use std::path::Path;
 
-    use hal::serial::{Read, Write};
+    use embedded_hal::serial::{Read, Write};
     use std::io::{Read as IoRead, Write as IoWrite};
 
     use super::*;

src/sysfs_pin.rs

@@ -26,7 +26,7 @@ impl SysfsPin {
     }
 }
 
-impl hal::digital::OutputPin for SysfsPin {
+impl embedded_hal::digital::OutputPin for SysfsPin {
     type Error = sysfs_gpio::Error;
 
     fn try_set_low(&mut self) -> Result<(), Self::Error> {
@@ -38,7 +38,7 @@ impl hal::digital::OutputPin for SysfsPin {
     }
 }
 
-impl hal::digital::InputPin for SysfsPin {
+impl embedded_hal::digital::InputPin for SysfsPin {
     type Error = sysfs_gpio::Error;
 
     fn try_is_high(&self) -> Result<bool, Self::Error> {

src/timer.rs

@@ -3,7 +3,7 @@
 use core::convert::Infallible;
 use std::time::{Duration, Instant};
 
-use hal::timer::{CountDown, Periodic};
+use embedded_hal::timer::{CountDown, Periodic};
 
 /// A periodic timer based on [`std::time::Instant`][instant], which is a
 /// monotonically nondecreasing clock.