首先设置RTC时间的节点名称，此次使用的是海思的RTC时间节点“hi_rtc”。

const char *dev_name = "/dev/hi_rtc";

以下是设置时间的函数，包括RTC时间和系统时间：

int set_hwtime(rtc_time_t *rtc_time)
{
    struct timeval val_time;
    struct tm tm_time;

    int fd = -1, ret = -1;
    fd = open(dev_name, O_RDWR);
    if (fd < 0) {
        printf("open %s failed\n", dev_name);
        return -1;
    }
    printf("set_hwtime: year=%d, month=%d, day=%d, hour=%d, min=%d, sec=%d\n",\
           rtc_time->year, rtc_time->month, rtc_time->date, rtc_time->hour, rtc_time->minute, rtc_time->second);

    ret = ioctl(fd, HI_RTC_SET_TIME, rtc_time);
    if (ret < 0) {
        printf("ioctl: HI_RTC_SET_TIME failed\n");
        return -1;
    }

    tm_time.tm_year  = rtc_time->year  - 1900;
    tm_time.tm_mon   = rtc_time->month - 1;
    tm_time.tm_mday  = rtc_time->date;
    tm_time.tm_hour  = rtc_time->hour;
    tm_time.tm_min   = rtc_time->minute;
    tm_time.tm_sec   = rtc_time->second;
    tm_time.tm_wday  = rtc_time->weekday;

    printf("set_systime: year=%d, month=%d, day=%d, hour=%d, min=%d, sec=%d\n",\
           rtc_time->year, rtc_time->month, rtc_time->date, rtc_time->hour, rtc_time->minute, rtc_time->second);

    val_time.tv_sec  = mktime(&tm_time);
    val_time.tv_usec = 0;
    settimeofday(&val_time,NULL);

    close(fd);
    return 0;
}

rtc时间通过ioctl的方式，将时间写入。系统时间通过settimeofday函数，将时间写入。最后完成需确认打开的句柄是否关闭close(fd)。