[Stratos-dev] Re: [PATCH V4 5/8] libgpiod: Add rust examples

On Fri, Jul 08, 2022 at 05:04:58PM +0530, Viresh Kumar wrote:

Add examples for the usage of the rust bindings, quite similar to the ones in cxx bindings.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org

bindings/rust/examples/gpiodetect.rs | 37 ++++++++++++ bindings/rust/examples/gpiofind.rs | 42 +++++++++++++ bindings/rust/examples/gpioget.rs | 42 +++++++++++++ bindings/rust/examples/gpioinfo.rs | 89 ++++++++++++++++++++++++++++ bindings/rust/examples/gpiomon.rs | 68 +++++++++++++++++++++ bindings/rust/examples/gpioset.rs | 52 ++++++++++++++++ 6 files changed, 330 insertions(+) create mode 100644 bindings/rust/examples/gpiodetect.rs create mode 100644 bindings/rust/examples/gpiofind.rs create mode 100644 bindings/rust/examples/gpioget.rs create mode 100644 bindings/rust/examples/gpioinfo.rs create mode 100644 bindings/rust/examples/gpiomon.rs create mode 100644 bindings/rust/examples/gpioset.rs

diff --git a/bindings/rust/examples/gpiodetect.rs b/bindings/rust/examples/gpiodetect.rs new file mode 100644 index 000000000000..82307e4eecea --- /dev/null +++ b/bindings/rust/examples/gpiodetect.rs @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of gpiodetect tool.

+use std::env; +use std::fs; +use std::path::Path;

+use libgpiod::{gpiod_is_gpiochip_device, Chip};

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() > 1 {

•    println!("Usage: {}", args[0]);
  

•    return;
  

• }
• for entry in fs::read_dir(Path::new("/dev")).unwrap() {

use .flatten() to have the iterator unwrap the entry so it is actually an entry, not a Result.

•    let pathbuf = entry.unwrap().path();
  

•    let path = pathbuf.to_str().unwrap();
  

is_gpiochip_device() and Chip::open() (and ChipInternal) should accept anything that can be converted into a &Path, e.g. a PathBuf, so the path variable becomes redundant.

e.g. pub(crate) fn open<P: AsRefstd::path::Path>(path: &P) -> Result<Self> { // Null-terminate the string let path = path.as_ref().to_string_lossy() + "\0"; ...

and then example code becomes:

for entry in fs::read_dir(Path::new("/dev")).unwrap().flatten() { let path = entry.path();

if gpiod_is_gpiochip_device(&path) { let chip = Chip::open(&path).unwrap(); ...

(renaming pathbuf to path)

Similarly other examples.

•    if gpiod_is_gpiochip_device(path) {
  

•        let chip = Chip::open(path).unwrap();
  

•        let ngpio = chip.get_num_lines();
  

Why does ngpio get a variable, unlike name and label?

•        println!(
  

•            "{} [{}] ({})",
  

•            chip.get_name().unwrap(),
  

•            chip.get_label().unwrap(),
  

•            ngpio
  

•        );
  

•    }
  

• }

+}

Avoid using unwrap(). Have main return a Result and use ?. Not so important here, but below for helper functions returning Results allows the caller to determine how to handle the error. And it reads better.

diff --git a/bindings/rust/examples/gpiofind.rs b/bindings/rust/examples/gpiofind.rs new file mode 100644 index 000000000000..bbbd7a87ece8 --- /dev/null +++ b/bindings/rust/examples/gpiofind.rs @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of gpiofind tool.

+use std::env; +use std::fs; +use std::path::Path;

+use libgpiod::{gpiod_is_gpiochip_device, Chip};

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() != 2 {

•    println!("Usage: {} <line-name>", args[0]);
  

•    return;
  

• }
• for entry in fs::read_dir(Path::new("/dev")).unwrap() {

•    let pathbuf = entry.unwrap().path();
  

•    let path = pathbuf.to_str().unwrap();
  

•    if gpiod_is_gpiochip_device(path) {
  

Perhaps have the bindings provide an iterator that returns the paths of available gpiochips?

•        let chip = Chip::open(path).unwrap();
  

•        let offset = chip.find_line(&args[1]);
  

•        if offset.is_ok() {
  

•            println!(
  

•                "Line {} found: Chip: {}, offset: {}",
  

•                args[1],
  

•                chip.get_name().unwrap(),
  

•                offset.unwrap()
  

•            );
  

•            return;
  

•        }
  

•    }
  

• }
• println!("Failed to find line: {}", args[1]);

+} diff --git a/bindings/rust/examples/gpioget.rs b/bindings/rust/examples/gpioget.rs new file mode 100644 index 000000000000..c3bc35fcfdb6 --- /dev/null +++ b/bindings/rust/examples/gpioget.rs @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of gpioget tool.

+use std::env;

+use libgpiod::{Chip, Direction, LineConfig, RequestConfig};

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() < 3 {

•    println!("Usage: {} <chip> <line_offset0> ...", args[0]);
  

•    return;
  

• }
• let mut config = LineConfig::new().unwrap();
• let mut offsets = Vec::<u32>::new();
• for arg in &args[2..] {

•    let offset = arg.parse::<u32>().unwrap();
  

•    offsets.push(offset);
  

•    config.set_direction_override(Direction::Input, offset);
  

• }
• let path = format!("/dev/gpiochip{}", args[1]);
• let chip = Chip::open(&path).unwrap();
• let rconfig = RequestConfig::new().unwrap();
• rconfig.set_consumer(&args[0]);
• rconfig.set_offsets(&offsets);
• let request = chip.request_lines(&rconfig, &config).unwrap();
• let mut values: Vec<i32> = vec![0; offsets.len()];
• request.get_values(&mut values).unwrap();
• println!("{:?}", values);

+} diff --git a/bindings/rust/examples/gpioinfo.rs b/bindings/rust/examples/gpioinfo.rs new file mode 100644 index 000000000000..bd30d9096ce8 --- /dev/null +++ b/bindings/rust/examples/gpioinfo.rs @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of gpioinfo tool.

+use std::env; +use std::fs; +use std::path::Path;

+use libgpiod::{gpiod_is_gpiochip_device, Chip, Direction};

+fn line_info(chip: &Chip, offset: u32) {

• let info = chip.line_info(offset).unwrap();
• let off = info.get_offset();
• let name = match info.get_name() {

•    Ok(name) => name,
  

•    _ => "unused",
  

• };
• let consumer = match info.get_consumer() {

•    Ok(name) => name,
  

•    _ => "unnamed",
  

• };
• let low = if info.is_active_low() {

•    "active-low"
  

• } else {

•    "active-high"
  

• };
• let dir = match info.get_direction().unwrap() {

•    Direction::AsIs => "None",
  

•    Direction::Input => "Input",
  

•    Direction::Output => "Output",
  

• };
• println!(

•    "\tline {:>3}\
  

•          \t{:>10}\
  

•          \t{:>10}\
  

•          \t{:>6}\
  

•          \t{:>14}",
  

•    off, name, consumer, dir, low
  

• );

+}

+fn chip_info(path: &str) {

• if gpiod_is_gpiochip_device(path) {

•    let chip = Chip::open(path).unwrap();
  

•    let ngpio = chip.get_num_lines();
  

•    println!("GPIO Chip name: {}", chip.get_name().unwrap());
  

•    println!("\tlabel: {}", chip.get_label().unwrap());
  

•    println!("\tpath: {}", chip.get_path().unwrap());
  

•    println!("\tngpio: {}\n", ngpio);
  

•    println!("\tLine information:");
  

•    for offset in 0..ngpio {
  

•        line_info(&chip, offset);
  

•    }
  

•    println!("\n");
  

• }

+}

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() > 2 {

•    println!("Usage: {}", args[0]);
  

•    return;
  

• }
• if args.len() == 1 {

•    for entry in fs::read_dir(Path::new("/dev")).unwrap() {
  

•        let pathbuf = entry.unwrap().path();
  

•        let path = pathbuf.to_str().unwrap();
  

•        chip_info(path);
  

•    }
  

• } else {

•    let index = args[1].parse::<u32>().unwrap();
  

•    let path = format!("/dev/gpiochip{}", index);
  

•    chip_info(&path);
  

• }

+} diff --git a/bindings/rust/examples/gpiomon.rs b/bindings/rust/examples/gpiomon.rs new file mode 100644 index 000000000000..872907b386f3 --- /dev/null +++ b/bindings/rust/examples/gpiomon.rs @@ -0,0 +1,68 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of the gpiomon tool.

+use std::env; +use std::time::Duration;

+use libgpiod::{Chip, Edge, EdgeEventBuffer, Error, LineConfig, LineEdgeEvent, RequestConfig};

+fn usage(name: &str) {

• println!("Usage: {} <chip> <offset0> ...", name);

+}

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() < 3 {

•    usage(&args[0]);
  

•    return;
  

• }
• let mut config = LineConfig::new().unwrap();
• let mut offsets = Vec::<u32>::new();
• for arg in &args[2..] {

•    let offset = arg.parse::<u32>().unwrap();
  

•    offsets.push(offset);
  

• }
• config.set_edge_detection_default(Edge::Both);
• let path = format!("/dev/gpiochip{}", args[1]);
• let chip = Chip::open(&path).unwrap();
• let rconfig = RequestConfig::new().unwrap();
• rconfig.set_offsets(&offsets);
• let buffer = EdgeEventBuffer::new(1).unwrap();
• let request = chip.request_lines(&rconfig, &config).unwrap();
• loop {

•    match request.wait_edge_event(Duration::new(1, 0)) {
  

•        Err(Error::OperationTimedOut) => continue,
  

timeout/continue required as you can't (currently) block indefinitely?

•        Err(x) => {
  

•            println!("{:?}", x);
  

•            return;
  

•        }
  

•        Ok(()) => (),
  

•    }
  

•    let count = request.read_edge_event(&buffer, 1).unwrap();
  

•    if count == 1 {
  

•        let event = buffer.get_event(0).unwrap();
  

•        println!(
  

•            "line: {} type: {}, time: {:?}",
  

•            event.get_line_offset(),
  

•            match event.get_event_type().unwrap() {
  

•                LineEdgeEvent::Rising => "Rising",
  

•                LineEdgeEvent::Falling => "Falling",
  

•            },
  

•            event.get_timestamp()
  

•        );
  

•    }
  

• }

+} diff --git a/bindings/rust/examples/gpioset.rs b/bindings/rust/examples/gpioset.rs new file mode 100644 index 000000000000..ef70e8edbaae --- /dev/null +++ b/bindings/rust/examples/gpioset.rs @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause +// +// Copyright 2022 Linaro Ltd. All Rights Reserved. +// Viresh Kumar viresh.kumar@linaro.org +// +// Simplified Rust implementation of the gpioset tool.

+use std::env;

+use libgpiod::{Chip, Direction, LineConfig, RequestConfig};

+fn usage(name: &str) {

• println!("Usage: {} <chip> <line_offset0>=<value0> ...", name);

+}

+fn main() {

• let args: Vec<String> = env::args().collect();
• if args.len() < 3 {

•    usage(&args[0]);
  

•    return;
  

• }
• let mut config = LineConfig::new().unwrap();
• let mut offsets = Vec::<u32>::new();
• let mut values = Vec::<i32>::new();
• for arg in &args[2..] {

•    let pair: Vec<&str> = arg.split('=').collect();
  

•    if pair.len() != 2 {
  

•        usage(&args[0]);
  

•        return;
  

•    }
  

•    let offset = pair[0].parse::<u32>().unwrap();
  

•    let value = pair[1].parse::<u32>().unwrap();
  

•    offsets.push(offset);
  

•    values.push(value as i32);
  

• }
• config.set_direction_default(Direction::Output);
• config.set_output_values(&offsets, &values).unwrap();
• let path = format!("/dev/gpiochip{}", args[1]);
• let chip = Chip::open(&path).unwrap();
• let rconfig = RequestConfig::new().unwrap();
• rconfig.set_consumer(&args[0]);
• rconfig.set_offsets(&offsets);
• chip.request_lines(&rconfig, &config).unwrap();

Wait rather than exiting immediately?

+}

2.31.1.272.g89b43f80a514

And, as mentioned elsewhere, add a gpiowatch example.

Cheers, Kent.