[−][src]Struct gpio_cdev::Line
Access to a specific GPIO Line
GPIO Lines must be obtained through a parent Chip
and
represent an actual GPIO pin/line accessible via that chip.
Not all accessible lines for a given chip may actually
map to hardware depending on how the board is setup
in the kernel.
Methods
impl Line
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pub fn info(&self) -> Result<LineInfo>
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Get info about the line from the kernel.
pub fn offset(&self) -> u32
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Offset of this line within its parent chip
pub fn chip(&self) -> Chip
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Get a handle to this chip's parent
pub fn request(
&self,
flags: LineRequestFlags,
default: u8,
consumer: &str
) -> Result<LineHandle>
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&self,
flags: LineRequestFlags,
default: u8,
consumer: &str
) -> Result<LineHandle>
Request access to interact with this line from the kernel
This is similar to the "export" operation present in the sysfs
API with the key difference that we are also able to configure
the GPIO with flags
to specify how the line will be used
at the time of request.
For an output, the default
parameter specifies the value
the line should have when it is configured as an output. The
consumer
string should describe the process consuming the
line (this will be truncated to 31 characters if too long).
Errors
The main source of errors here is if the kernel returns an
error to the ioctl performing the request here. This will
result in an Error
being returned with ErrorKind::Io
.
One possible cause for an error here would be if the line is
already in use. One can check for this prior to making the
request using is_kernel
.
pub fn events(
&self,
handle_flags: LineRequestFlags,
event_flags: EventRequestFlags,
consumer: &str
) -> Result<LineEventHandle>
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&self,
handle_flags: LineRequestFlags,
event_flags: EventRequestFlags,
consumer: &str
) -> Result<LineEventHandle>
Get an event handle that can be used as a blocking iterator over the events (state changes) for this Line
When used as an iterator, it blocks while there is not another event
available from the kernel for this line matching the subscription
criteria specified in the event_flags
. The line will be configured
with the specified handle_flags
and consumer
label.
Note that as compared with the sysfs interface, the character device interface maintains a queue of events in the kernel so events may happen (e.g. a line changing state faster than can be picked up in userspace in real-time). These events will be returned on the iterator in order with the event containing the associated timestamp attached with high precision within the kernel (from an ISR for most drivers).
Example
use gpio_cdev::*; let mut chip = Chip::new("/dev/gpiochip0")?; let input = chip.get_line(0)?; // Show all state changes for this line forever for event in input.events( LineRequestFlags::INPUT, EventRequestFlags::BOTH_EDGES, "rust-gpio" )? { println!("{:?}", event?); }
Trait Implementations
impl Clone for Line
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fn clone(&self) -> Line
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
impl Debug for Line
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Auto Trait Implementations
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,