linux led驱动例程（杂项设备）

    #include <linux/module.h>//与module相关的信息    #include <linux/kernel.h>    #include <linux/init.h>      //与init相关的函数    #include <linux/platform_device.h>    #include <linux/miscdevice.h>    #include <linux/fs.h>    /***gpio申请和释放***/    #include <linux/gpio.h>    /*******************/    #include <plat/gpio-cfg.h>    /*********************/    #include <mach/gpio-exynos4.h>    #include <mach/gpio.h>    /***************用到的函数与结构体******************    extern int platform_driver_register(struct platform_driver *);    extern void platform_driver_unregister(struct platform_driver *);            int (*probe)(struct platform_device *);            int (*remove)(struct platform_device *);            void (*shutdown)(struct platform_device *);            int (*suspend)(struct platform_device *, pm_message_t state);            int (*resume)(struct platform_device *);    杂项设备结构体    struct miscdevice  {            int minor;            const char *name;            const struct file_operations *fops;            struct list_head list;            struct device *parent;            struct device *this_device;            const char *nodename;            mode_t mode;    };    extern int misc_register(struct miscdevice * misc);    extern int misc_deregister(struct miscdevice *misc);    struct file_operations {            struct module *owner;             long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);            long (*compat_ioctl) (struct file *, unsigned int, unsigned long);            int (*mmap) (struct file *, struct vm_area_struct *);            int (*open) (struct inode *, struct file *);            int (*flush) (struct file *, fl_owner_t id);            int (*release) (struct inode *, struct file *);            int (*fsync) (struct file *, int datasync);            int (*aio_fsync) (struct kiocb *, int datasync);            int (*fasync) (int, struct file *, int);            int (*lock) (struct file *, int, struct file_lock *);    static inline int gpio_request(unsigned gpio, const char *label)    static inline void gpio_free(unsigned gpio)    static inline void gpio_set_value(unsigned gpio, int value)    EXYNOS4_GPIO_L2    s3c_gpio_cfgpin(unsigned int pin, unsigned int to);    S3C_GPIO_OUTPUT    **********************************/    MODULE_LICENSE("GPL");    MODULE_AUTHOR("zhangsan");    #define DRIVER_NAME "hello_ctl"    #define DEVICE_NAME "hello_ctl"    static long hello_ioctl(struct file *file, unsigned int cmd, unsigned long arg)    {        printk(KERN_INFO "The cmd is %d,arg is %d\n",cmd,arg);        if(cmd>1)        {           printk(KERN_INFO "cmd should be 0 or 1\n");        }        if(arg>1)           printk(KERN_INFO "arg must be 1\n");        gpio_set_value(EXYNOS4_GPL2(0), cmd);//关闭        return 0;    }    static int hello_release(struct inode *inode, struct file *file)    {        printk(KERN_INFO "hello_release\n");            return 0;    }    static int hello_open(struct inode *inode, struct file *file)    {        printk(KERN_INFO "hello_open\n");           return 0;    }    static struct file_operations hello_ops={        .owner=THIS_MODULE,        .open=hello_open,        .release=hello_release,        .unlocked_ioctl=hello_ioctl,    };    static struct miscdevice hello_dev={        .minor=MISC_DYNAMIC_MINOR,        .name=DEVICE_NAME,        .fops=&hello_ops,    };    static int hello_probe(struct platform_device *pdv)    {        int ret;        printk(KERN_INFO "program inited!\n");        ret=gpio_request(EXYNOS4_GPL2(0),"LED1");        if(ret<0)        {           printk(KERN_INFO "request gpio failed\n");           return ret;          }        s3c_gpio_cfgpin(EXYNOS4_GPL2(0),S3C_GPIO_OUTPUT);        gpio_set_value(EXYNOS4_GPL2(0), 0);//关闭        misc_register(&hello_dev);        return 0;    }    static int hello_remove(struct platform_device *pdv)    {        gpio_free(EXYNOS4_GPL2(0));        misc_deregister(&hello_dev);        return 0;    }    static void hello_shutdown(struct platform_device *pdv)    {        printk(KERN_INFO "hello_shutdown\n");       }    static int hello_suspend(struct platform_device *pdv)    {        printk(KERN_INFO "Hello_suspend\n");        return 0;    }    static int hello_resume(struct platform_device *pdv)    {        printk(KERN_INFO "Hello_resume\n");        return 0;    }    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 hellodriver_init()    {        int Driverstate;        //printk(KERN_INFO "Hello_init\n");        Driverstate=platform_driver_register(&hello_driver);        printk(KERN_INFO "Driverstate is %d\n",Driverstate);        return 0;    }    static void hellodriver_exit()    {        printk(KERN_INFO "Hello_exit\n");        platform_driver_unregister(&hello_driver);    }    module_init(hellodriver_init);    module_exit(hellodriver_exit);