diff options
Diffstat (limited to 'src/serial.c')
| -rw-r--r-- | src/serial.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/serial.c b/src/serial.c new file mode 100644 index 00000000..26cf59d7 --- /dev/null +++ b/src/serial.c @@ -0,0 +1,209 @@ +/* + * serial.c + * + * Utility functions to deal with serial ports + * + * Copyright (C) 2011 Sylvain Munaut <tnt@246tNt.com> + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/*! \addtogroup serial + * @{ + */ + +/*! \file serial.c + * \file Osmocom serial port helpers + */ + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <termios.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <linux/serial.h> + + +#include <osmocom/core/serial.h> + + +#if 0 +# define dbg_perror(x) perror(x) +#else +# define dbg_perror(x) do { } while (0) +#endif + +/*! \brief Open serial device and does base init + * \param[in] dev Path to the device node to open + * \param[in] baudrate Baudrate constant (speed_t: B9600, B...) + * \returns >=0 file descriptor in case of success or negative errno. + */ +int +osmo_serial_init(const char *dev, speed_t baudrate) +{ + int rc, fd=0, v24; + struct termios tio; + + /* Open device */ + fd = open(dev, O_RDWR | O_NOCTTY | O_NDELAY); + if (fd < 0) { + dbg_perror("open"); + return -errno; + } + + /* Configure serial interface */ + rc = tcgetattr(fd, &tio); + if (rc < 0) { + dbg_perror("tcgetattr()"); + rc = -errno; + goto error; + } + + cfsetispeed(&tio, baudrate); + cfsetospeed(&tio, baudrate); + + tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS); + tio.c_cflag |= (CREAD | CLOCAL | CS8); + tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); + tio.c_iflag |= (INPCK | ISTRIP); + tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR); + tio.c_oflag &= ~(OPOST | ONLCR); + + rc = tcsetattr(fd, TCSANOW, &tio); + if (rc < 0) { + dbg_perror("tcsetattr()"); + rc = -errno; + goto error; + } + + /* Set ready to read/write */ + v24 = TIOCM_DTR | TIOCM_RTS; + rc = ioctl(fd, TIOCMBIS, &v24); + if (rc < 0) { + dbg_perror("ioctl(TIOCMBIS)"); + rc = -errno; + goto error; + } + + return fd; + +error: + if (fd) + close(fd); + return rc; +} + +static int +_osmo_serial_set_baudrate(int fd, speed_t baudrate) +{ + int rc; + struct termios tio; + + rc = tcgetattr(fd, &tio); + if (rc < 0) { + dbg_perror("tcgetattr()"); + return -errno; + } + cfsetispeed(&tio, baudrate); + cfsetospeed(&tio, baudrate); + + rc = tcsetattr(fd, TCSANOW, &tio); + if (rc < 0) { + dbg_perror("tcgetattr()"); + return -errno; + } + + return 0; +} + +/*! \brief Change current baudrate + * \param[in] fd File descriptor of the open device + * \param[in] baudrate Baudrate constant (speed_t: B9600, B...) + * \returns 0 for success or negative errno. + */ +int +osmo_serial_set_baudrate(int fd, speed_t baudrate) +{ + osmo_serial_clear_custom_baudrate(fd); + return _osmo_serial_set_baudrate(fd, baudrate); +} + +/*! \brief Change current baudrate to a custom one using OS specific method + * \param[in] fd File descriptor of the open device + * \param[in] baudrate Baudrate as integer + * \returns 0 for success or negative errno. + * + * This function might not work on all OS or with all type of serial adapters + */ +int +osmo_serial_set_custom_baudrate(int fd, int baudrate) +{ + int rc; + struct serial_struct ser_info; + + rc = ioctl(fd, TIOCGSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCGSERIAL)"); + return -errno; + } + + ser_info.flags = ASYNC_SPD_CUST | ASYNC_LOW_LATENCY; + ser_info.custom_divisor = ser_info.baud_base / baudrate; + + rc = ioctl(fd, TIOCSSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCSSERIAL)"); + return -errno; + } + + return _osmo_serial_set_baudrate(fd, B38400); /* 38400 is a kind of magic ... */ +} + +/*! \brief Clear any custom baudrate + * \param[in] fd File descriptor of the open device + * \returns 0 for success or negative errno. + * + * This function might not work on all OS or with all type of serial adapters + */ +int +osmo_serial_clear_custom_baudrate(int fd) +{ + int rc; + struct serial_struct ser_info; + + rc = ioctl(fd, TIOCGSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCGSERIAL)"); + return -errno; + } + + ser_info.flags = ASYNC_LOW_LATENCY; + ser_info.custom_divisor = 0; + + rc = ioctl(fd, TIOCSSERIAL, &ser_info); + if (rc < 0) { + dbg_perror("ioctl(TIOCSSERIAL)"); + return -errno; + } + + return 0; +} + +/*! }@ */ |