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// SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
// SPDX-FileCopyrightText: 2022 Linaro Ltd.
// SPDX-FileCopyrightText: 2022 Viresh Kumar <viresh.kumar@linaro.org>
#[cfg(feature = "v2_1")]
use std::ffi::CStr;
use std::os::unix::prelude::AsRawFd;
use std::time::Duration;
use super::{
Error, OperationType, Result, gpiod,
line::{self, Offset, Value, ValueMap},
request,
};
/// Line request operations
///
/// Allows interaction with a set of requested lines.
#[derive(Debug, Eq, PartialEq)]
pub struct Request {
pub(crate) request: *mut gpiod::gpiod_line_request,
}
// SAFETY: Request models a wrapper around an owned gpiod_line_request and may
// be safely sent to other threads.
unsafe impl Send for Request {}
impl Request {
/// Request a set of lines for exclusive usage.
///
/// SAFETY: The pointer must point to an instance that is valid. After
/// constructing a [Request] the pointer MUST NOT be used for any other
/// purpose anymore. All interactions with the libgpiod API have to happen
/// through this object.
pub(crate) unsafe fn from_raw(request: *mut gpiod::gpiod_line_request) -> Result<Self> {
Ok(Self { request })
}
/// Get the name of the chip this request was made on.
#[cfg(feature = "v2_1")]
pub fn chip_name(&self) -> Result<&str> {
// SAFETY: The `gpiod_line_request` is guaranteed to be live as long
// as `&self`
let name = unsafe { gpiod::gpiod_line_request_get_chip_name(self.request) };
// SAFETY: The string is guaranteed to be valid, non-null and immutable
// by the C API for the lifetime of the `gpiod_line_request`.
unsafe { CStr::from_ptr(name) }
.to_str()
.map_err(Error::StringNotUtf8)
}
/// Get the number of lines in the request.
pub fn num_lines(&self) -> usize {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
unsafe { gpiod::gpiod_line_request_get_num_requested_lines(self.request) }
}
/// Get the offsets of lines in the request.
pub fn offsets(&self) -> Vec<Offset> {
let mut offsets = vec![0; self.num_lines()];
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let num_offsets = unsafe {
gpiod::gpiod_line_request_get_requested_offsets(
self.request,
offsets.as_mut_ptr(),
self.num_lines(),
)
};
offsets.shrink_to(num_offsets);
offsets
}
/// Get the value (0 or 1) of a single line associated with the request.
pub fn value(&self, offset: Offset) -> Result<Value> {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let value = unsafe { gpiod::gpiod_line_request_get_value(self.request, offset) };
if value != 0 && value != 1 {
Err(Error::OperationFailed(
OperationType::LineRequestGetVal,
errno::errno(),
))
} else {
Value::new(value)
}
}
/// Get values of a subset of lines associated with the request.
pub fn values_subset(&self, offsets: &[Offset]) -> Result<ValueMap> {
let mut values = vec![0; offsets.len()];
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret = unsafe {
gpiod::gpiod_line_request_get_values_subset(
self.request,
offsets.len(),
offsets.as_ptr(),
values.as_mut_ptr(),
)
};
if ret == -1 {
Err(Error::OperationFailed(
OperationType::LineRequestGetValSubset,
errno::errno(),
))
} else {
let mut map = ValueMap::new();
for (i, val) in values.iter().enumerate() {
map.insert(offsets[i], Value::new(*val)?);
}
Ok(map)
}
}
/// Get values of all lines associated with the request.
pub fn values(&self) -> Result<ValueMap> {
self.values_subset(&self.offsets())
}
/// Set the value of a single line associated with the request.
pub fn set_value(&mut self, offset: Offset, value: Value) -> Result<&mut Self> {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret =
unsafe { gpiod::gpiod_line_request_set_value(self.request, offset, value.value()) };
if ret == -1 {
Err(Error::OperationFailed(
OperationType::LineRequestSetVal,
errno::errno(),
))
} else {
Ok(self)
}
}
/// Set values of a subset of lines associated with the request.
pub fn set_values_subset(&mut self, map: ValueMap) -> Result<&mut Self> {
let mut offsets = Vec::new();
let mut values = Vec::new();
for (offset, value) in map {
offsets.push(offset);
values.push(value.value());
}
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret = unsafe {
gpiod::gpiod_line_request_set_values_subset(
self.request,
offsets.len(),
offsets.as_ptr(),
values.as_ptr(),
)
};
if ret == -1 {
Err(Error::OperationFailed(
OperationType::LineRequestSetValSubset,
errno::errno(),
))
} else {
Ok(self)
}
}
/// Set values of all lines associated with the request.
pub fn set_values(&mut self, values: &[Value]) -> Result<&mut Self> {
if values.len() != self.num_lines() {
return Err(Error::InvalidArguments);
}
let mut new_values = Vec::new();
for value in values {
new_values.push(value.value());
}
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret =
unsafe { gpiod::gpiod_line_request_set_values(self.request, new_values.as_ptr()) };
if ret == -1 {
Err(Error::OperationFailed(
OperationType::LineRequestSetVal,
errno::errno(),
))
} else {
Ok(self)
}
}
/// Update the configuration of lines associated with the line request.
pub fn reconfigure_lines(&mut self, lconfig: &line::Config) -> Result<&mut Self> {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret =
unsafe { gpiod::gpiod_line_request_reconfigure_lines(self.request, lconfig.config) };
if ret == -1 {
Err(Error::OperationFailed(
OperationType::LineRequestReconfigLines,
errno::errno(),
))
} else {
Ok(self)
}
}
/// Wait for edge events on any of the lines associated with the request.
pub fn wait_edge_events(&self, timeout: Option<Duration>) -> Result<bool> {
let timeout = match timeout {
Some(x) => x.as_nanos() as i64,
// Block indefinitely
None => -1,
};
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
let ret = unsafe { gpiod::gpiod_line_request_wait_edge_events(self.request, timeout) };
match ret {
-1 => Err(Error::OperationFailed(
OperationType::LineRequestWaitEdgeEvent,
errno::errno(),
)),
0 => Ok(false),
_ => Ok(true),
}
}
/// Get a number of edge events from a line request.
///
/// This function will block if no event was queued for the line.
pub fn read_edge_events<'a>(
&self,
buffer: &'a mut request::Buffer,
) -> Result<request::Events<'a>> {
buffer.read_edge_events(self)
}
}
impl AsRawFd for Request {
/// Get the file descriptor associated with the line request.
fn as_raw_fd(&self) -> i32 {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
unsafe { gpiod::gpiod_line_request_get_fd(self.request) }
}
}
impl Drop for Request {
/// Release the requested lines and free all associated resources.
fn drop(&mut self) {
// SAFETY: `gpiod_line_request` is guaranteed to be valid here.
unsafe { gpiod::gpiod_line_request_release(self.request) }
}
}