/*
 * Copyright (C) 2024 LingYun IoT System Studio
 * Author: Guo Wenxue <guowenxue@gmail.com>
 *
 * A character skeleton driver test code in user space.
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>

#define CHR_MAGIC       'c'
#define CMD_READ        _IOR(CHR_MAGIC, 0, int)
#define CMD_WRITE       _IOW(CHR_MAGIC, 1, int)

int main (int argc, char **argv)
{
    char      *devname = "/dev/chrdev0";
    int        value;
    int        fd;

    fd = open(devname, O_RDWR);
    if( fd < 0 )
    {
        printf("Open device %s failed: %s\n", devname, strerror(errno));
        return 1;
    }

    if( ioctl(fd, CMD_READ, &value) < 0 )
    {
        printf("ioctl() failed: %s\n", strerror(errno));
        goto cleanup;
    }
    printf("Default value in driver: 0x%0x\n", value);

    value = 0x12345678;
    if( ioctl(fd, CMD_WRITE, &value) < 0 )
    {
        printf("ioctl() failed: %s\n", strerror(errno));
        goto cleanup;
    }
    printf("Wriee value into driver: 0x%0x\n", value);

    value = 0;
    if( ioctl(fd, CMD_READ, &value) < 0 )
    {
        printf("ioctl() failed: %s\n", strerror(errno));
        goto cleanup;
    }
    printf("Read value from driver : 0x%0x\n", value);

cleanup:
    close(fd);
    return 0;
}