七、【misc】杂项驱动模型

一、杂项设备驱动设计步骤

1、定义一个杂项设备结构体

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struct miscdevice  {     int minor;                    //次设备号     const char *name;       //设备名和设备文件名一致     const struct file_operations *fops;  //文件操作集合     struct list_head list;     struct device *parent;     struct device *this_device;     const char *nodename;     umode_t mode; };

2、杂项设备的注册和注销

（1）注册

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1	int misc_register(struct miscdevice * misc)

（2）注销

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1	int misc_deregister(struct miscdevice *misc)

二、使用杂项设备模型写led流水灯驱动

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#include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/cdev.h> #include <linux/fs.h> #include <linux/device.h> #include <linux/ioport.h> #include <linux/io.h> #include <linux/uaccess.h> #include <linux/types.h> #include <linux/gpio.h> #include <cfg_type.h> #include <linux/miscdevice.h>   #define LED_ON  _IOW('L',0,unsigned long)   #define LED_OFF _IOW('L',1,unsigned long)   struct led_gpio_t{     unsigned int gpio;     char gpio_name[20]; };     static struct led_gpio_t led_gpioC[]= {     {PAD_GPIO_C+17,"D8_GPIOC17"},     {PAD_GPIO_C+7,"D9_GPIOC7"},     {PAD_GPIO_C+8,"D10_GPIOC8"}, };       static long led_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) {     if(arg>10||arg<7)    {     return -EINVAL;    }     switch(cmd)     {         case LED_ON:             gpio_set_value(led_gpioC[arg-8].gpio,0);             break;         case LED_OFF:             gpio_set_value(led_gpioC[arg-8].gpio,1);             break;         default:             return -ENOIOCTLCMD;        }     return 0; }   struct file_operations led_misc_fops= {     .unlocked_ioctl = led_ioctl, };   static struct miscdevice led_misc={     .minor = MISC_DYNAMIC_MINOR,   //表示由系统分配次设备号     .name = "led_misc",     .fops =  &led_misc_fops,     }; static int __init  led_init(void) {       int ret,i;        printk(KERN_INFO"led_init\n");       ret = misc_register(&led_misc);       if(ret < 0)       {             printk(KERN_INFO"led misc register fail.\n");         goto misc_register_err;       }     for(i=0;i<3;i++)     {          ret = gpio_request(led_gpioC[i].gpio, led_gpioC[i].gpio_name);          if(ret < 0)          {             printk(KERN_INFO"gpio_request fail.\n");             goto gpio_request_err;          }     }     for(i=0;i<3;i++)     {         gpio_direction_output(led_gpioC[i].gpio, 1);     }     return 0;   gpio_request_err:     while(i--)     {         gpio_free(led_gpioC[i].gpio);     } misc_register_err:         return 0; }   static void __exit led_exit(void) {     int i;     printk(KERN_INFO"xxxx__exit\n");       for(i=0;i<3;i++)      {         gpio_free(led_gpioC[i].gpio);      }      misc_deregister(&led_misc);      } module_init(led_init); module_exit(led_exit); MODULE_LICENSE("GPL");

main.c

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#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <sys/ioctl.h>     #define LED_ON  _IOW('L',0,unsigned long)   #define LED_OFF _IOW('L',1,unsigned long) int main() {     int fd,ret;       char buff[2]={0};     fd = open("/dev/led_misc",O_RDWR);     if(fd<0)     {         perror("open led_misc error!");            }     while(1)     {         ioctl(fd,LED_ON,8);         sleep(1);         ioctl(fd,LED_OFF,8);         ioctl(fd,LED_ON,9);         sleep(1);          ioctl(fd,LED_OFF,9);         ioctl(fd,LED_ON,10);         sleep(1);         ioctl(fd,LED_OFF,10);               }            close(fd);      return 0; }