代码示例_数据传递

---

//头文件
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/slab.h>

#include <asm/io.h>
#include <asm/uaccess.h>


//面向对象编程----设计设备的类型
struct s5pv210_led{
    unsigned int major;
    struct class * cls;
    struct device * dev;
    int data;
};
struct s5pv210_led *led_dev;

volatile unsigned long *gpco_conf;
volatile unsigned long *gpco_data;


//实现设备操作接口
int led_open(struct inode *inode, struct file *filp)
{

    printk("--------^_^ %s------------
",__FUNCTION__);
    //将对应的管脚设置为输出
    *gpco_conf &= ~(0xff<<12);   //19--12清0
    *gpco_conf |= 0x11<<12;        //19---12赋值:00010001

    return 0;
}
ssize_t led_write(struct file *filp, const char __user *buf, size_t size, loff_t *flags)
{
    int ret;
    printk("--------^_^ %s------------
",__FUNCTION__);

    //应用空间数据转换为内核空间数据
    ret = copy_from_user(&led_dev->data,buf,size);
    if(ret != 0){
        printk("copy_from_user error!
");
        return -EFAULT;
    }

    if(led_dev->data){
        //点灯
        *gpco_data |= 0x3<<3;
    }else{
        //灭灯
        *gpco_data &= ~(0x3<<3);
    }

    return size;
}

int led_close(struct inode *inode, struct file *filp)
{
    printk("--------^_^ %s------------
",__FUNCTION__);
    //灭灯
        *gpco_data &= ~(0x3<<3);
    return 0;
}


static struct file_operations fops = {
    .open = led_open,
    .write = led_write,
    .release = led_close,
};


//加载函数和卸载函数
static int __init led_init(void)   //加载函数-----在驱动被加载时执行
{
    int ret;
    printk("--------^_^ %s------------
",__FUNCTION__);
    //0,实例化设备对象
    //参数1 ---- 要申请的空间的大小
    //参数2 ---- 申请的空间的标识
    led_dev = kzalloc(sizeof(struct s5pv210_led),GFP_KERNEL);
    if(IS_ERR(led_dev)){
        printk("kzalloc error!
");
        ret = PTR_ERR(led_dev);
        return -ENOMEM;
    }
    
    //1,申请设备号
#if 0
    //静态申请主设备号
    led_dev->major = 256;
    ret = register_chrdev(led_dev->major,"led_drv",&fops);
    if(ret < 0){
        printk("register_chrdev error!
");
        return -EINVAL;
    }
#else
    //动态申请主设备号
    led_dev->major = register_chrdev(0,"led_drv",&fops);
    if(led_dev->major < 0){
        printk("register_chrdev error!
");
        ret =  -EINVAL;
        goto err_kfree;
    }
#endif

    //2,创建设备文件-----/dev/led1
    led_dev->cls = class_create(THIS_MODULE,"led_cls");
    if(IS_ERR(led_dev->cls)){
        printk("class_create error!
");
        ret = PTR_ERR(led_dev->cls);
        goto err_unregister;
    }
    
    led_dev->dev = device_create(led_dev->cls,NULL,MKDEV(led_dev->major,0),NULL,"led");
    if(IS_ERR(led_dev->dev)){
        printk("device_create error!
");
        ret = PTR_ERR(led_dev->dev);
        goto err_class;
    }


    //3,硬件初始化----地址映射

        gpco_conf = ioremap(0xE0200060,8);
        gpco_data = gpco_conf+1;
    
    return 0;

err_class:
    class_destroy(led_dev->cls);

err_unregister:
    unregister_chrdev(led_dev->major,"led_drv");
    
err_kfree:
    kfree(led_dev);
    return ret;

    
}

static void __exit led_exit(void)   //卸载函数-----在驱动被卸载时执行
{
    printk("--------^_^ %s------------
",__FUNCTION__);
    device_destroy(led_dev->cls,MKDEV(led_dev->major,0));
    class_destroy(led_dev->cls);
    unregister_chrdev(led_dev->major,"led_drv");
    kfree(led_dev);
}

//声明和认证
module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");

---

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

int main(void)
{

    int fd;
    int on;

    fd = open("/dev/led",O_RDWR);
    if(fd < 0){
        perror("open");
        exit(1);
    }

    //闪灯
    while(1){
        //点灯
        on = 1;
        write(fd,&on,sizeof(on));
        sleep(1);

        //灭灯
        on = 0;
        write(fd,&on,sizeof(on));
        sleep(1);
    }

    close(fd);
    return 0;
}

---

#指定内核源码路径
KERNEL_DIR = /home/farsight/s5pv210/kernel/linux-3.0.8
CUR_DIR = $(shell pwd)
MYAPP = test

all:
    #让make进入内核源码编译，同时将当前目录中的c程序作为内核模块一起编译
    make -C $(KERNEL_DIR) M=$(CUR_DIR) modules
    arm-none-linux-gnueabi-gcc -o $(MYAPP) $(MYAPP).c

clean:
    #删除上面编译生成的文件
    make -C $(KERNEL_DIR) M=$(CUR_DIR) clean
    rm -rf $(MYAPP)

install:
    cp *.ko $(MYAPP) /opt/rootfs/drv_module

#指定当前目录下哪个文件作为内核模块编
obj-m = led_drv.o