/*********************************************************************************
 *      Copyright:  (C) 2023 Avnet
 *                  All rights reserved.
 *
 *       Filename:  file.c
 *    Description:  This file 
 *                 
 *        Version:  1.0.0(2023年11月02日)
 *         Author:  Guo Wenxue <guowenxue@avnet.com>
 *      ChangeLog:  1, Release initial version on "2023年11月02日 14时47分52秒"
 *                 
 ********************************************************************************/

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

/* ioctl definitions, use 'z' as magic number */
#define CHRDEV_IOC_MAGIC  'z'
#define CHRDEV_IOCRESET    _IO(CHRDEV_IOC_MAGIC, 0)
#define CHRDEV_IOCSET      _IOW(CHRDEV_IOC_MAGIC, 1, int)
#define CHRDEV_IOCGET      _IOR(CHRDEV_IOC_MAGIC, 2, int)

int main (int argc, char **argv)
{
	char      *devname = "/dev/chrdev";
	char       buf[1024];
	int        rv, fd;
	int        value = 0x12345678;

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

	rv = write(fd, "Hello", 5);
	if( rv< 0)
	{
		printf("Write data into device failed, rv=%d: %s\n", rv, strerror(errno));
		return 2;
	}
	printf("Write %d bytes data okay\n", rv);

#if 0
	lseek(fd, 3, SEEK_SET);
#endif

	memset(buf, 0, sizeof(buf));
	rv = read(fd, buf, sizeof(buf));
	if( rv< 0)
	{
		printf("Read data from device failed, rv=%d: %s\n", rv, strerror(errno));
		return 3;
	}
	printf("Read %d bytes data: %s\n", rv, buf);

#if 0
	ioctl(fd, CHRDEV_IOCSET, &value);
	value = 0;
	ioctl(fd, CHRDEV_IOCGET, &value);
	printf("ioctl() read value=0x%0x\n", value);
#endif

	close(fd);
	return 0;
}