/*
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* Copyright (C) 2024 LingYun IoT System Studio
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* Author: Guo Wenxue <guowenxue@gmail.com>
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*
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* A character skeleton driver test code in user space.
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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 <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#define CHR_MAGIC 'c'
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#define CMD_READ _IOR(CHR_MAGIC, 0, int)
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#define CMD_WRITE _IOW(CHR_MAGIC, 1, int)
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int main (int argc, char **argv)
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{
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char *devname = "/dev/chrdev0";
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int value;
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int fd;
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fd = open(devname, O_RDWR);
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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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if( ioctl(fd, CMD_READ, &value) < 0 )
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{
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printf("ioctl() failed: %s\n", strerror(errno));
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goto cleanup;
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}
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printf("Default value in driver: 0x%0x\n", value);
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value = 0x12345678;
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if( ioctl(fd, CMD_WRITE, &value) < 0 )
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{
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printf("ioctl() failed: %s\n", strerror(errno));
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goto cleanup;
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}
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printf("Wriee value into driver: 0x%0x\n", value);
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value = 0;
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if( ioctl(fd, CMD_READ, &value) < 0 )
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{
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printf("ioctl() failed: %s\n", strerror(errno));
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goto cleanup;
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}
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printf("Read value from driver : 0x%0x\n", value);
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cleanup:
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close(fd);
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return 0;
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}
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