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基于i.MX6ULL的掉電檢測設計與軟件測試 基于i.MX6ULL平臺設計實現掉電檢測功能，首先選擇一路IO，利用IO電平變化觸發中斷，在編寫驅動時捕獲該路GPIO的中斷，然后在中斷響應函數中發送信號通知應用程序掉電發生了。 圖1.1掉電信號IO 驅動代碼: #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #definepower_MAJOR 200 staticstruct class *my_class; staticstruct fasync_struct *fasync_queue; //異步通知隊列 #defineGPIO_NUM 1 //中斷引腳為：GPIO1_1 staticunsigned int irq_num; /* 打開 */ intpower_open(struct inode *inode,struct file *filp){ return 0; } /* 關閉 */ intpower_release(struct inode *inode,struct file *filp){ return 0; } ssize_tpower_read(struct file *filp,char __user *buf,size_t count,loff_t *f_pos){ return count; } ssize_tpower_write(struct file *file,const char __user *buf,size_t count,loff_t*f_pos){ return count; } staticint my_fasync(int fd, struct file * filp, int on) { int retval; retval=fasync_helper(fd,filp,on,&fasync_queue); /*將該設備登記到fasync_queue隊列中去*/ if(retval<0) return retval; return 0; } staticconst struct file_operations simple_fops={ .owner=THIS_MODULE, .open=power_open, .release=power_release, .read=power_read, .write=power_write, .fasync=my_fasync, }; /* 在中斷服務函數中向應用層發送消息-異步通知 */ staticirqreturn_t irq_callback (int irqno, void *dev_id){ printk("irq power-detectworking !\n"); if (fasync_queue) { kill_fasync(&fasync_queue, SIGIO,POLL_IN); } return IRQ_HANDLED; } intpower_init_module(void){ int rtn; int ret; /* 注冊設備驅動 */ ret =register_chrdev(power_MAJOR,"power-detect-test",&simple_fops); if(ret<0){ printk("Unable toregister character device %d!/n",ret); return ret; } /* 自動創建設備節點 */ my_class = class_create(THIS_MODULE,"my_class"); device_create(my_class, NULL,MKDEV(power_MAJOR, 0), NULL,"powerdetect"); /*gpio申請*/ rtn = gpio_request(GPIO_NUM,"my_irq"); if(rtn!=0){ printk("my_irq irq pinrequest io failed.\n"); } rtn = gpio_direction_input(GPIO_NUM); if(rtn<0){ printk("gpio_direction_input()failed !\n"); } /*獲取gpio中斷號*/ irq_num = gpio_to_irq(GPIO_NUM); /*GPIO中斷服務函數注冊，*/ /*下降沿觸發*/ rtn = request_irq(irq_num,irq_callback,IRQF_TRIGGER_FALLING,"my_irq", NULL); if (rtn<0) { printk("my_irq requestirq false\n"); } else { printk("my_irq requestirq success: %d\n",irq_num); } printk("module_initsucessful!!!\n"); return 0; } /* 卸載 */ voidpower_cleanup_module(void){ /* 卸載相應的設備驅動 */ unregister_chrdev(power_MAJOR,"power-detect-test"); device_destroy(my_class,MKDEV(power_MAJOR,0)); class_destroy(my_class); /*釋放GPIO*/ gpio_free(GPIO_NUM); printk("module_exitsucessful!!!\n"); } /* 宏實現 */ module_init(power_init_module); module_exit(power_cleanup_module); /* 開源許可聲明 */ MODULE_LICENSE("GPL"); MODULE_AUTHOR("Zou"); 應用代碼: #include #include #include #include #include #include staticint fd; /* 內核產生異步通知,調用該應用層函數處理 */ voidsigterm_handler(int signo) { printf("app irq work !!!\n"); } intmain(void) { int oflags; fd=open("/dev/powerdetect",O_RDWR); //打開設備文件 /* 啟動異步通知信號驅動機制 */ signal(SIGIO, sigterm_handler); fcntl(fd, F_SETOWN, getpid()); oflags = fcntl(fd, F_GETFL); fcntl(fd, F_SETFL, oflags | FASYNC); /*建立一個死循環，防止程序結束 */ while(1) { printf("sleep\n"); usleep(200000); //2ms } close(fd); return 0; } 將驅動編譯成模塊，上電加載并執行應用程序后，將電壓緩慢下調至掉電臨界點。觸發GPIO下降沿中斷，并提供應用程序掉電信號。 圖1..2掉電檢測 |
