linux c 编程 ------ 通过设备节点调用驱动

 驱动程序如下，加载驱动后，会在/dev文件夹下生成一个文件hello_device_node，是此驱动的设备节点

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>

#define DRIVER_NAME "hello"
#define NODE_NAME "hello_device_node"

MODULE_LICENSE("Dual BSD/GPL"); // required
MODULE_AUTHOR("liuShuiDeng");


static long hello_fs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    printk("\ncmd is %d, arg is %ld\n", cmd, arg);
    return 0;
}
static int hello_fs_release(struct inode *inode, struct file *file)
{
    printk(KERN_EMERG "\nhello_fs_release\n");
    return 0;
}
static int hello_fs_open(struct inode *inode, struct file *file)
{
    printk(KERN_EMERG "\nhello_fs_open\n");
    return 0;
}
static struct file_operations hello_fops = {
    .owner = THIS_MODULE,
    .open = hello_fs_open,
    .release = hello_fs_release,
    .unlocked_ioctl = hello_fs_ioctl,
};
static struct miscdevice hello_miscdevice = {
    .minor = MISC_DYNAMIC_MINOR,
    .name = NODE_NAME,
    .fops = &hello_fops,
};
static int hello_probe(struct platform_device *p)
{
    printk(KERN_EMERG "\nhello_probe\n");
    misc_register(&hello_miscdevice);
    return 0;
}

static int hello_remove(struct platform_device *p)
{
    printk(KERN_EMERG "\nhello_remove\n");
    misc_deregister(&hello_miscdevice);
    return 0;
}

static void hello_shutdown(struct platform_device *p)
{
    printk(KERN_EMERG "\nhello_shutdown\n");
}

static int hello_suspend(struct platform_device *p, pm_message_t state)
{
    printk(KERN_EMERG "\nhello_suspend\n");
    
    return 0;
}

static int hello_resume(struct platform_device *p)
{
    printk(KERN_EMERG "\nhello_resume\n");
    
    return 0;
}

static struct platform_driver hello_driver={
    .probe = hello_probe,
    .remove = hello_remove,
    .shutdown = hello_shutdown,
    .suspend = hello_suspend,
    .resume = hello_resume,
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
    },
};

static int hello_init(void) //insmod xxx.ko, execute it
{
    printk(KERN_EMERG "\nhello world enter~\n\n");
    platform_driver_register(&hello_driver);
    return 0;    
}

static void hello_exit(void) //rmmod xxx( note: not xxx.ko ), execute it
{
    printk(KERN_EMERG "\nhello world exit~\n\n");
    platform_driver_unregister(&hello_driver);
}



module_init(hello_init);
module_exit(hello_exit);

应用程序如下

编译驱动程序的编译器和编译应用程序的编译器建议用同一个

编译应用程序指令：arm-none-linux-gnueabi-gcc -o invoke_hello invoke_hello.c

修改权限指令：chmod 777 invoke_hello

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


void main()
{
    int fd;
    char *hello_node = "/dev/hello_device_node";

    fd = open(hello_node, O_RDWR|O_NDELAY);
    if(fd < 0)
    {
        printf("APP---->can't open \"%s\"\n",hello_node);
    }else
    {
        printf("APP--->open \"%s\" successfully\n", hello_node);
        ioctl(fd,1,2);
    }

    close(fd);
}