/*********************************************************************************
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* Copyright: (C) 2023 Avnet
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* All rights reserved.
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*
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* Filename: file.c
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* Description: This file
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*
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* Version: 1.0.0(2023年11月02日)
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* Author: Guo Wenxue <guowenxue@avnet.com>
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* ChangeLog: 1, Release initial version on "2023年11月02日 14时47分52秒"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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/* ioctl definitions, use 'z' as magic number */
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#define CHRDEV_IOC_MAGIC 'z'
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#define CHRDEV_IOCRESET _IO(CHRDEV_IOC_MAGIC, 0)
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#define CHRDEV_IOCSET _IOW(CHRDEV_IOC_MAGIC, 1, int)
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#define CHRDEV_IOCGET _IOR(CHRDEV_IOC_MAGIC, 2, int)
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int main (int argc, char **argv)
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{
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char *devname = "/dev/chrdev";
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char buf[1024];
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int rv, fd;
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int value = 0x12345678;
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fd = open(devname, O_RDWR|O_TRUNC);
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if( fd < 0 )
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{
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printf("Open device %s failed: %s\n", devname, strerror(errno));
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return 1;
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}
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rv = write(fd, "Hello", 5);
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if( rv< 0)
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{
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printf("Write data into device failed, rv=%d: %s\n", rv, strerror(errno));
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return 2;
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}
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printf("Write %d bytes data okay\n", rv);
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#if 0
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lseek(fd, 3, SEEK_SET);
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#endif
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memset(buf, 0, sizeof(buf));
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rv = read(fd, buf, sizeof(buf));
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if( rv< 0)
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{
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printf("Read data from device failed, rv=%d: %s\n", rv, strerror(errno));
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return 3;
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}
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printf("Read %d bytes data: %s\n", rv, buf);
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#if 0
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ioctl(fd, CHRDEV_IOCSET, &value);
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value = 0;
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ioctl(fd, CHRDEV_IOCGET, &value);
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printf("ioctl() read value=0x%0x\n", value);
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#endif
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close(fd);
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return 0;
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}
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