tty.h File Reference

#include <sys/types.h>
#include <zephyr/types.h>
#include <zephyr/kernel.h>

Go to the source code of this file.

Data Structures
struct	tty_serial

Functions
int	tty_init (struct tty_serial *tty, const struct device *uart_dev)
	Initialize serial port object (classically known as tty).
static void	tty_set_rx_timeout (struct tty_serial *tty, int32_t timeout)
	Set receive timeout for tty device.
static void	tty_set_tx_timeout (struct tty_serial *tty, int32_t timeout)
	Set transmit timeout for tty device.
int	tty_set_rx_buf (struct tty_serial *tty, void *buf, size_t size)
	Set receive buffer for tty device.
int	tty_set_tx_buf (struct tty_serial *tty, void *buf, size_t size)
	Set transmit buffer for tty device.
ssize_t	tty_read (struct tty_serial *tty, void *buf, size_t size)
	Read data from a tty device.
ssize_t	tty_write (struct tty_serial *tty, const void *buf, size_t size)
	Write data to tty device.

Function Documentation

tty_init()

int tty_init	(	struct tty_serial *	tty,
		const struct device *	uart_dev )

Initialize serial port object (classically known as tty).

"tty" device provides support for buffered, interrupt-driven, timeout-controlled access to an underlying UART device. For completeness, it also support non-interrupt-driven, busy-polling access mode. After initialization, tty is in the "most conservative" unbuffered mode with infinite timeouts (this is guaranteed to work on any hardware). Users should configure buffers and timeouts as they need using functions tty_set_rx_buf(), tty_set_tx_buf(), tty_set_rx_timeout(), tty_set_tx_timeout().

Parameters

tty	tty device structure to initialize
uart_dev	underlying UART device to use (should support interrupt-driven operation)

Returns

0 on success, error code (<0) otherwise

tty_read()

ssize_t tty_read	(	struct tty_serial *	tty,
		void *	buf,
		size_t	size )

Read data from a tty device.

Parameters

tty	tty device structure
buf	buffer to read data to
size	maximum number of bytes to read

Returns

>0, number of actually read bytes (can be less than size param) =0, for EOF-like condition (e.g., break signaled) <0, in case of error (e.g. -EAGAIN if timeout expired). errno variable is also set.

tty_set_rx_buf()

int tty_set_rx_buf	(	struct tty_serial *	tty,
		void *	buf,
		size_t	size )

Set receive buffer for tty device.

Set receive buffer or switch to unbuffered operation for receive.

Parameters

tty	tty device structure
buf	buffer, or NULL for unbuffered operation
size	buffer buffer size, 0 for unbuffered operation

Returns

0 on success, error code (<0) otherwise: EINVAL: unsupported buffer (size)

tty_set_rx_timeout()

static void tty_set_rx_timeout ( struct tty_serial * tty, int32_t timeout )

inlinestatic

Set receive timeout for tty device.

Set timeout for getchar() operation. Default timeout after device initialization is SYS_FOREVER_MS.

Parameters

tty	tty device structure
timeout	timeout in milliseconds, or 0, or SYS_FOREVER_MS.

tty_set_tx_buf()

int tty_set_tx_buf	(	struct tty_serial *	tty,
		void *	buf,
		size_t	size )

Set transmit buffer for tty device.

Set transmit buffer or switch to unbuffered operation for transmit. Note that unbuffered mode is implicitly blocking, i.e. behaves as if tty_set_tx_timeout(SYS_FOREVER_MS) was set.

Parameters

tty	tty device structure
buf	buffer, or NULL for unbuffered operation
size	buffer buffer size, 0 for unbuffered operation

Returns

0 on success, error code (<0) otherwise: EINVAL: unsupported buffer (size)

tty_set_tx_timeout()

static void tty_set_tx_timeout ( struct tty_serial * tty, int32_t timeout )

inlinestatic

Set transmit timeout for tty device.

Set timeout for putchar() operation, for a case when output buffer is full. Default timeout after device initialization is SYS_FOREVER_MS.

Parameters

tty	tty device structure
timeout	timeout in milliseconds, or 0, or SYS_FOREVER_MS.

tty_write()

ssize_t tty_write	(	struct tty_serial *	tty,
		const void *	buf,
		size_t	size )

Write data to tty device.

Parameters

tty	tty device structure
buf	buffer containing data
size	maximum number of bytes to write

Returns

=>0, number of actually written bytes (can be less than size param) <0, in case of error (e.g. -EAGAIN if timeout expired). errno variable is also set.