Struct sysfs_gpio::Pin [−][src]
pub struct Pin { /* fields omitted */ }
Implementations
Create a new Pin with the provided pin_num
This function does not export the provided pin_num.
Create a new Pin with the provided path
This form is useful when there are other scripts which may
have already exported the GPIO and created a symlink with a
nice name that you already have reference to. Otherwise, it
is generally preferrable to use new
directly.
The provided path must be either the already exported directory for a GPIO or a symlink to one. If the directory does not look sufficiently like this (i.e. does not resolve to a path starting with /sys/class/gpioXXX), then this function will return an error.
Get the pin number
Run a closure with the GPIO exported
Prior to the provided closure being executed, the GPIO will be exported. After the closure execution is complete, the GPIO will be unexported.
Example
use sysfs_gpio::{Pin, Direction};
let gpio = Pin::new(24);
let res = gpio.with_exported(|| {
println!("At this point, the Pin is exported");
gpio.set_direction(Direction::Low)?;
gpio.set_value(1)?;
// ...
Ok(())
});
Determines whether the GPIO is exported
This function will error out if the kernel does not support the GPIO
sysfs interface (i.e. /sys/class/gpio
does not exist).
Export the GPIO
This is equivalent to echo N > /sys/class/gpio/export
with
the exception that the case where the GPIO is already exported
is not an error.
Errors
The main cases in which this function will fail and return an error are the following:
- The system does not support the GPIO sysfs interface
- The requested GPIO is out of range and cannot be exported
- The requested GPIO is in use by the kernel and cannot be exported by use in userspace
Example
use sysfs_gpio::Pin;
let gpio = Pin::new(24);
match gpio.export() {
Ok(()) => println!("Gpio {} exported!", gpio.get_pin()),
Err(err) => println!("Gpio {} could not be exported: {}", gpio.get_pin(), err),
}
Unexport the GPIO
This function will unexport the provided by from syfs if it is currently exported. If the pin is not currently exported, it will return without error. That is, whenever this function returns Ok, the GPIO is not exported.
Get the direction of the Pin
Set this GPIO as either an input or an output
The basic values allowed here are Direction::In
and
Direction::Out
which set the Pin as either an input
or output respectively. In addition to those, two
additional settings of Direction::High
and
Direction::Low
. These both set the Pin as an output
but do so with an initial value of high or low respectively.
This allows for glitch-free operation.
Note that this entry may not exist if the kernel does not support changing the direction of a pin in userspace. If this is the case, you will get an error.
Get the value of the Pin (0 or 1)
If successful, 1 will be returned if the pin is high and 0 will be returned if the pin is low (this may or may not match the signal level of the actual signal depending on the GPIO “active_low” entry).
Set the value of the Pin
This will set the value of the pin either high or low. A 0 value will set the pin low and any other value will set the pin high (1 is typical).
Get the currently configured edge for this pin
This value will only be present if the Pin allows for interrupts.
Set the edge on which this GPIO will trigger when polled
The configured edge determines what changes to the Pin will
result in poll()
returning. This call will return an Error
if the pin does not allow interrupts.
Get polarity of the Pin (true
is active low)
Set the polarity of the Pin (true
is active low)
This will affect “rising” and “falling” edge triggered configuration.
Get a PinPoller object for this pin
This pin poller object will register an interrupt with the kernel and allow you to poll() on it and receive notifications that an interrupt has occured with minimal delay.
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Pin
impl UnwindSafe for Pin
Blanket Implementations
Mutably borrows from an owned value. Read more