Struct gpio_cdev::MultiLineHandle

pub struct MultiLineHandle { /* fields omitted */ }

Handle for interacting with a "requested" line

In order for userspace to read/write the value of a GPIO it must be requested from the chip using Line::request. On success, the kernel creates an anonymous file descriptor for interacting with the requested line. This structure is the go-between for callers and that file descriptor.

Methods

impl MultiLineHandle

pub fn get_values(&self) -> Result<Vec<u8>>

Request the current state of this Line from the kernel

This call is expected to succeed for both input and output lines. It should be noted, however, that some drivers may not be able to give any useful information when the value is requested for an output line.

This value should be 0 or 1 which a "1" representing that the line is active. Usually this means that the line is at logic-level high but it could mean the opposite if the line has been marked as being ACTIVE_LOW.

pub fn set_values(&self, values: &[u8]) -> Result<()>

Request that the line be driven to the specified value

The value should be 0 or 1 with 1 representing a request to make the line "active". Usually "active" means logic level high unless the line has been marked as ACTIVE_LOW.

Calling set_value on a line that is not an output will likely result in an error (from the kernel).

pub fn num_lines(&self) -> usize

Get the number of lines associated with this handle

pub fn lines(&self) -> &Lines

Get the Line information associated with this handle.

Trait Implementations

impl Debug for MultiLineHandle

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl AsRawFd for MultiLineHandle

fn as_raw_fd(&self) -> RawFd

Gets the raw file descriptor for the LineHandle.