android 字符设备驱动模块及在 /dev 下自动创建设备节点问题
转载时请注明出处和作者文章出处：http://blog.csdn.net/lbmygf/archive/2011/06/16/6547946.aspx
作者：曼云-->孤峰
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define MRY_MAJOR 99
#define uint unsigned int
#define ulong unsigned long
static int mry_major=MRY_MAJOR;
typedef struct
{
struct cdev dev;
//add private data
}mry_dev;
mry_dev *_pdev;
static int mry_open(struct inode *pinode,struct file *pfile)
{
printk("in open now--------------------------------------------------------/n");
return 0;
}
static int mry_ioctl(struct inode *pinode,struct file *pfile,uint cmd,ulong arg)
{
printk("cmd == %d arg == %ld --------------------------------------------------------/n", cmd, arg);
switch(cmd)
{
case 1:
break;
default:
return -1;
}
return 0;
}
static const struct file_operations _fops=
{
.owner=THIS_MODULE,
.ioctl=mry_ioctl,
.open=mry_open,
};
static void mry_setup_cdev(mry_dev *pdev,int index)
{
int err,devno=MKDEV(mry_major,index);
cdev_init(&pdev->dev,&_fops);
pdev->dev.owner=THIS_MODULE;
pdev->dev.ops=&_fops;
err=cdev_add(&pdev->dev,devno,1);
if(err)
printk(KERN_NOTICE "Error %d adding LED %d",err,index);
}
struct class *my_class;
int mry_init(void)
{
int rs;
dev_t devno=MKDEV(mry_major,0); //获取设备节点号
if(mry_major)
rs=register_chrdev_region(devno,1,"gps_sleep"); // 注册gps_sleep 设备
else
{
rs=alloc_chrdev_region(&devno,0,1,"gps_sleep"); //动态注册gps_sleep设备，也就是自动获取设备号
mry_major=MAJOR(devno); //获取主设备号
}
if(rs<0){
return rs;
}
_pdev=kmalloc(sizeof(mry_dev),GFP_KERNEL); //为 _pdev分配空间
if(!_pdev)
{
rs=-ENOMEM;
goto fail_malloc;
}
memset(_pdev,0,sizeof(mry_dev)); //初始化_pdev
mry_setup_cdev(_pdev,0);
my_class = class_create(THIS_MODULE, "gps_sleep");
//class_create和device_create 自动在/dev目录下创建设备节点gps_sleep
if(IS_ERR(my_class))
{
printk("Err: failed in creating class.--------------------------------------------/n");
return -1;
}
device_create(my_class, NULL, MKDEV(mry_major, 0), NULL, "gps_sleep");
//在这里需要注意了，由于内核版本不同，导致device_create的参数可能有变化，
//我就遇到了，在网上找了一个，一用就出问题了，系统会跑死，现在这个的内核是2.6.35的
printk(KERN_INFO "mry driver ok----------------------------------------------------------------");
return 0;
fail_malloc:
printk(KERN_INFO "failed");
unregister_chrdev_region(devno,1);
return rs;
}
void mry_exit(void)
{
dev_t devno = MKDEV (mry_major, 0);
cdev_del(&_pdev->dev);
device_destroy(my_class, MKDEV(mry_major, 0)); //delete device node under /dev
class_destroy(my_class); //delete class created by us
kfree(_pdev);
unregister_chrdev_region(MKDEV(mry_major,0),1);
}
module_init(mry_init);
module_exit(mry_exit);
MODULE_AUTHOR("liu");
MODULE_DESCRIPTION("gps sleep wake driver");
MODULE_LICENSE("GPL");