MQ-2烟雾气敏传感器模块在X210v3开发板上的驱动。
现在需要一个MQ-2烟雾气敏传感器模块的驱动。其检测烟雾超过一定的标准后,会返回一个不同的电平,和按键驱动差不多。
但是在编写驱动的时候,需要用GPH2_3号引脚。但是在内核中先ioremap地址然后配置,发现无法控制gpio,也无法进入中断。
后来发现,如果需要使用gpio,需要先申请,然后才能使用。
具体程序如下:
#include <linux/module.h> #include <linux/init.h> #include <linux/miscdevice.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/fs.h> #include <linux/slab.h> #include <asm/irq.h> #include <linux/random.h> #include <linux/uaccess.h> #include <linux/device.h> #include <mach/gpio.h> #define GPH2CON 0xE0200c60 #define GPH2DAT 0xE0200c64 static struct class *fog_class; //创建类 static struct class_device *fog_class_devs; //创建类对应的设备 struct work_struct *work1; struct timer_list fogs_timer; unsigned int *gpio_data; unsigned int fog_num = 0; wait_queue_head_t fog_q; void work1_func(struct work_struct *work) { mod_timer(&fogs_timer, jiffies + (HZ /10)); } void fogs_timer_function(unsigned long data) { unsigned int fog_val; fog_val = readw(gpio_data)&0x08; if (fog_val == 0) { fog_num = 1; printk("press down "); } wake_up(&fog_q); } irqreturn_t fog_int(int irq, void *dev_id) { schedule_work(work1); //return 0; return IRQ_HANDLED; } void fog_hw_init() { unsigned int *gpio_config; unsigned short data; gpio_request(S5PV210_GPH2(3),"my_fog"); gpio_config = ioremap(GPH2CON,4); data = readw(gpio_config); data &= ~(0b1111<<12); data |= 0b1111<<12; writew(data,gpio_config); gpio_data = ioremap(GPH2DAT,1); } int fog_open(struct inode *node,struct file *filp) { return 0; } ssize_t fog_read(struct file *filp, char __user *buf, size_t size, loff_t *pos) { wait_event(fog_q,fog_num); // printk("in kernel :fog num is %d ",fog_num); copy_to_user(buf, &fog_num, 4); fog_num = 0; return 4; } struct file_operations fog_fops = { .open = fog_open, .read = fog_read, }; struct miscdevice fog_miscdev = { .minor = 200, .name = "fog", .fops = &fog_fops, }; int major; static int fog_init() { int ret; major = register_chrdev( 0,"fog_drv", &fog_fops ); fog_class = class_create(THIS_MODULE,"fog_class"); fog_class_devs = device_create(fog_class,NULL,MKDEV(major,0),NULL,"my_fog"); if (ret !=0) printk("register fail! "); //×¢²áÖжώŠÀí³ÌÐò request_irq(IRQ_EINT(27),fog_int,IRQF_TRIGGER_FALLING,"fog",0); //°ŽŒü³õÊŒ»¯ fog_hw_init(); //. ŽŽœš¹€×÷ work1 = kmalloc(sizeof(struct work_struct),GFP_KERNEL); INIT_WORK(work1, work1_func); /* ³õÊŒ»¯¶šÊ±Æ÷ */ init_timer(&fogs_timer); fogs_timer.function = fogs_timer_function; /* ÏòÄÚºË×¢²áÒ»žö¶šÊ±Æ÷ */ add_timer(&fogs_timer); /*³õÊŒ»¯µÈŽý¶ÓÁÐ*/ init_waitqueue_head(&fog_q); return 0; } static void fog_exit() { del_timer(&fogs_timer); unregister_chrdev( major, "fog_drv" ); device_unregister(fog_class_devs); class_destroy(fog_class); } module_init(fog_init); module_exit(fog_exit); MODULE_LICENSE("GPL");