hx-serial/hx_serial.c

#include "hx_serial.h"

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <assert.h>
#include <fcntl.h>
#include <termios.h>
#include "logc/log.h"

int by_serial_init(by_serial_t *serial_port, const char *dev_name)
{
  serial_port->dev_name_len = strlen(dev_name);
  assert(0 < serial_port->dev_name_len);
  strcpy(serial_port->dev_name_str, dev_name);

  int fd;
  fd = open(serial_port->dev_name_str, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK);
  if (fd < 0) {
    log_error("open uart device error");
    return -1;
  } else {
    serial_port->fd = fd;
    by_serial_set_baudrate(serial_port, 115200);
    by_serial_set_parity(serial_port, 8, 1, 'N');
    log_info("serial %s init successful", serial_port->dev_name_str);
    return 0;
  }
}

int by_serial_set_baudrate(by_serial_t *serial_port, int baudrate)
{
  int index       = 0;
  int status      = 0;
  int speed_arr[] = {
      B115200,
      B38400,
      B19200,
      B9600,
      B4800,
      B2400,
      B1200};
  int name_arr[] = {
      115200,
      38400,
      19200,
      9600,
      4800,
      2400,
      1200};
  struct termios Opt = {0};

  tcgetattr(serial_port->fd, &Opt);
  for (index = 0; index < sizeof(speed_arr) / sizeof(int); index++) {
    if (baudrate == name_arr[index]) {

      /*设置前 flush*/
      tcflush(serial_port->fd, TCIOFLUSH);
      cfsetispeed(&Opt, speed_arr[index]);
      cfsetospeed(&Opt, speed_arr[index]);

      /*tcsetattr(串口描述符，立即使用或者其他标示，指向 termios 的指针)，通过
      tcsetattr 函数把新的属性设置到串口上。*/
      status = tcsetattr(serial_port->fd, TCSANOW, &Opt);
      if (0 != status) {
        log_error("tcsetattr COM error");
        return -1;
      }

      /*设置后 flush*/
      tcflush(serial_port->fd, TCIOFLUSH);
      return 0;
    }
  }

  return 0;
}

int by_serial_set_parity(by_serial_t *serial_port, int databits, int stopbits, char parity)
{
  struct termios Opt = {0};

  if (0 != tcgetattr(serial_port->fd, &Opt)) {
    log_error("tcgetattr COM error");
    return -1;
  }

  Opt.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
  Opt.c_oflag &= ~OPOST;                          /*Output*/

  Opt.c_iflag &= ~ICRNL;  // 禁止将输入的 CR 转换为 NL
  Opt.c_iflag &= ~(IXON); // 清 bit 位 关闭流控字符

  /*设置数据位，取值为 7 或 8*/
  Opt.c_cflag &= ~CSIZE;
  switch (databits) {
    case 7:
      Opt.c_cflag |= CS7;
      break;
    case 8:
      Opt.c_cflag |= CS8;
      break;
    default:
      log_error("Unsupported data size");
      return -1;
      break;
  }

  /*设置停止位，取值为 1 或 2*/
  switch (stopbits) {
    case 1:
      Opt.c_cflag &= ~CSTOPB;
      break;
    case 2:
      Opt.c_cflag |= CSTOPB;
      break;
    default:
      log_error("Unsupported stop bits");
      return -1;
      break;
  }

  /*设置校验位，取值为 E,N,O,S*/
  switch (parity) {
    case 'e':
    case 'E': {
      Opt.c_cflag |= PARENB;  /*Enable parity*/
      Opt.c_cflag &= ~PARODD; /*转换为偶效验*/
      Opt.c_iflag |= INPCK;   /*Disnable parity checking*/
    } break;
    case 'n':
    case 'N': {
      Opt.c_cflag &= ~PARENB; /*Clear parity enable*/
      Opt.c_iflag &= ~INPCK;  /*Enable parity checking*/
    } break;
    case 'o':
    case 'O': {
      Opt.c_cflag |= (PARODD | PARENB); /*设置为奇效验*/
      Opt.c_iflag |= INPCK;             /*Disnable parity checking*/
    } break;
    case 's': /*as no parity*/
    case 'S': /*as no parity*/
    {
      Opt.c_cflag &= ~PARENB;
      Opt.c_cflag &= ~CSTOPB;
    } break;
    default:
      log_error("Unsupported parity\n");
      return -1;
      break;
  }

  /*设置结构体输入校验位*/
  if ('n' != parity) {
    Opt.c_iflag |= INPCK;
  }

  tcflush(serial_port->fd, TCIFLUSH);
  Opt.c_cc[VTIME] = 150; /*设置超时 15 秒*/
  Opt.c_cc[VMIN]  = 0;   /*更新结构体并立即执行*/
  if (0 != tcsetattr(serial_port->fd, TCSANOW, &Opt)) {
    log_error("tcsetattr COM error");
    return -1;
  }

  return 0;
}

int by_serial_write(by_serial_t *serial_port, const char *buff, const int len)
{
  int len_t;

  if (serial_port->fd < 0) {
    return -1;
  }

  len_t = write(serial_port->fd, buff, len);

  if (0 > len_t) {
    // log_error("write buff failed");
    return -1;
  } else {
    // printf("write buff successful %d/%d\r\n", len_t, len);
    return 0;
  }
}

int by_serial_read(by_serial_t *serial_port, char *buff, const int len)
{
  if (1 > by_serial_get_used_buffer_len(serial_port)) {
    return -1;
  }

  int len_t = -1;

  if (serial_port->fd < 0) {
    return -1;
  }

  len_t = read(serial_port->fd, buff, len);

  if (0 > len_t) {
    // log_error("read buff failed");
    return -1;
  } else {
    // printf("read buff successful %d/%d\r\n", len_t, len);
    return len_t;
  }
}

int by_serial_get_used_buffer_len(by_serial_t *serial_port)
{
  int used_len = 0;
  ioctl(serial_port->fd, FIONREAD, &used_len);
  return used_len;
}