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Linux PWM Access via Sysfs in Rust

License: Apache License 2.0

Rust 100.00%

linux rust sysfs pwm embedded

rust-sysfs-pwm's Introduction

sysfs-pwm

API Documentation

rust-sysfs-pwm is a rust library/crate providing access to the Linux sysfs PWM interface. It seeks to provide an API that is safe, convenient, and efficient.

Install/Use

To use sysfs-pwm, first add this to your Cargo.toml:

[dependencies]
# or latest version
sysfs-pwm = "0.2.0"

Then, add this to your crate root:

use sysfs_pwm;

MSRV (Minimum Supported Rust Version)

This crate is guaranteed to compile on stable Rust 1.28.0 and up. It might compile with older versions but that may change in any new patch release.

Example/API

The main API consists of a Pwm struct with the following methods:

Pwm::new - Create a Pwm instance
pwm.with_exported - Execute a block with the Pwm exported
pwm.set_active - Enable/Disable the Pwm
pwm.get_duty_cycle - Get duty cycle as percentage of period
pwm.set_duty_cycle - Set duty cycle as percentage of period
pwm.get_duty_cycle_ns - Get duty cycle in nanoseconds
pwm.set_duty_cycle_ns - Set duty cyle in nanoseconds
pwm.get_period_ns - Get the Pwm period in nanoseconds
pwm.set_period_ns - Set the Pwm period in nanoseconds

Check out the Breathing LED example for a usage example.

Cross Compiling

Most likely, the machine you are running on is not your development machine (although it could be). In those cases, you will need to cross-compile. The instructions here provide great details on cross compiling for your platform.

Running the Example

Cross-compiling can be done by specifying an appropriate target. You can then move that to your device by whatever means and run it.

$ cargo build --target=arm-unknown-linux-gnueabihf --example breathe
$ scp target/arm-unknown-linux-gnueabihf/debug/examples/breathe ...

License

Licensed under either of

Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Code of Conduct

Contribution to this crate is organized under the terms of the Rust Code of Conduct, the maintainer of this crate, the Embedded Linux Team, promises to intervene to uphold that code of conduct.

rust-sysfs-pwm's People

Contributors

Stargazers

Watchers

Forkers

cwoodall ekmecic kofron istar-eldritch posborne amarok1412 leseulartichaut andful mdegans binarier myszon contradict lucavuitton eldruin mpi3d iq-scm

rust-sysfs-pwm's Issues

Do you accept pull requests?

Looking to add capture support to the library and I was wondering if you accept pull requests.

Crate panic on Beaglebone green (seed)

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Io(Os { code: 2, kind: NotFound, message: "No such file or directory" })', src/libcore/result.rs:999:5
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.29/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:47
   3: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:36
   4: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:200
   5: std::panicking::default_hook
             at src/libstd/panicking.rs:214
   6: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:477
   7: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:384
   8: rust_begin_unwind
             at src/libstd/panicking.rs:311
   9: core::panicking::panic_fmt
             at src/libcore/panicking.rs:85
  10: core::result::unwrap_failed
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libcore/macros.rs:18
  11: core::result::Result<T,E>::unwrap
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libcore/result.rs:800
  12: cucaracha::pwmled::PwmLed::new
             at src/pwmled.rs:40
  13: cucaracha::main
             at src/main.rs:22
  14: std::rt::lang_start::{{closure}}
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
  15: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:49
  16: std::panicking::try::do_call
             at src/libstd/panicking.rs:296
  17: __rust_maybe_catch_panic
             at src/libpanic_unwind/lib.rs:82
  18: std::panicking::try
             at src/libstd/panicking.rs:275
  19: std::panic::catch_unwind
             at src/libstd/panic.rs:394
  20: std::rt::lang_start_internal
             at src/libstd/rt.rs:48
  21: std::rt::lang_start
             at /rustc/eae3437dfe991621e8afdc82734f4a172d7ddf9b/src/libstd/rt.rs:64
  22: main
  23: __libc_start_main

because the crate is trying to get /sys/class/pwm/pwmchip{}/pwm{}/{} where on my beaglebone it's /sys/class/pwm/pwmchip4/pwm-4\:0/

The line in my code causing this is pwm.enable(true).unwrap();

Could you point me to the right directions on what should I look for?

sysfs-pwm on crates.io homepage and documentation should point somewhere else

On the sysfs-pwm crate page in crates.io homepage points to posborne/rust-sysfs-pwm and the documentation points to here (404 page)

Using /dev/mem to toggle pins.

Tracking the use of /dev/mem to toggle pins.

Details:
http://chiragnagpal.com/examples.html

Not sure if this library is the appropriate home for this?