一、原理图

二、中断表

三、设备树

四、说明

本次实验是在按键中断的基础上修改，原理图和设备树不变，使用中断下半部机制，介绍work和tasklet两种实现下半部的方式。
方式一：tasklet

方式二：

五、tasklet方式实现下半部的驱动程序

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/string.h>
#include <linux/irq.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#define DeviceName 		"devicetree-key0-interrupt-tasklet" //设备驱动名称
#define DeviceNodes 	1 					  	 //设备节点个数
#define KEY_NUM 		0X01             
#define KEY0VALUE       0X01
#define INVAKEY         0XFF
struct irq_keydesc{int gpio_num;           /* io编号 */int irq_num;            /* 中断号 */unsigned char value;    /* 键值 */char name[25];          /* 名字 */irqreturn_t (*handler) (int, void *);  /* 中断处理函数 */struct tasklet_struct tasklet;
};
/* 定义一个设备结构体 */
struct mod_struct {dev_t devid;			     /* 设备号 */int major;				     /* 主设备号 */int minor;				     /* 次设备号 */struct cdev cdev;		     /* cdev */struct class *class;	  	 /* 类 */struct device *device;	 	 /* 设备 */struct device_node *nd;  	 /* 设备节点 */struct irq_keydesc irqkey0;  /* 按键中断 */struct timer_list timer;	 /* 内核定时器 */atomic_t keyvalue;			 /* 原子变量1->整形*/atomic_t releasekey;		 /* 原子变量2->整形*/
};
struct mod_struct mod_device;	 /* 定义一个设备 */
/** @description		: 打开设备* @param - inode 	: 传递给驱动的inode* @param - filp 	: 设备文件，file结构体有个叫做private_data的成员变量* 					  一般在open的时候将private_data指向设备结构体。* @return 			: 0 成功;其他 失败*/
static int key0_interrupt_open(struct inode *inode, struct file *filp)
{filp->private_data = &mod_device; /* 设置私有数据 */return 0;
}
/** @description		: 从设备读取数据 * @param - filp 	: 要打开的设备文件(文件描述符)* @param - buf 	: 返回给用户空间的数据缓冲区* @param - cnt 	: 要读取的数据长度* @param - offt 	: 相对于文件首地址的偏移* @return 			: 读取的字节数，如果为负值，表示读取失败*/
static ssize_t key0_interrupt_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{int ret = 0;unsigned char keyvalue;unsigned char releasekey;struct mod_struct *dev = filp->private_data;keyvalue = atomic_read(&dev->keyvalue);releasekey = atomic_read(&dev->releasekey);if(releasekey) {        /* 有效按键 */if(keyvalue & 0x80) {keyvalue &= ~0x80;ret = copy_to_user(buf, &keyvalue, sizeof(keyvalue));} else {goto data_error;}atomic_set(&dev->releasekey, 0); /* 按下标志清零 */} else {goto data_error;}return ret;data_error:return -EINVAL;
}
/** @description		: 向设备写数据 * @param - filp 	: 设备文件，表示打开的文件描述符* @param - buf 	: 要写给设备写入的数据* @param - cnt 	: 要写入的数据长度* @param - offt 	: 相对于文件首地址的偏移* @return 			: 写入的字节数，如果为负值，表示写入失败*/
static ssize_t key0_interrupt_write(struct file *filp, const char __user *buf,size_t cnt, loff_t *offt)
{return 0;
}
/** @description		: 关闭/释放设备* @param - filp 	: 要关闭的设备文件(文件描述符)* @return 			: 0 成功;其他 失败*/static int key0_interrupt_release(struct inode *inode, struct file *filp)
{return 0;
}
/* 设备操作函数 */
static struct file_operations beep_fops = {.owner    	=  THIS_MODULE,.open     	=  key0_interrupt_open,.read     	=  key0_interrupt_read,.write    	=  key0_interrupt_write,.release  	=  key0_interrupt_release,
};
/* 按键中断处理函数 */
static irqreturn_t key0_handler(int irq, void *dev_id)
{struct mod_struct *dev = dev_id;#if 0dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(20)); /* 20ms定时 */#endiftasklet_schedule(&dev->irqkey0.tasklet);return IRQ_HANDLED;
}
/* tasklet (下半部)*/
static void key_tasklet(unsigned long data)
{struct mod_struct *dev = (struct mod_struct*)data;dev->timer.data = data;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(20)); /* 20ms定时 */
}/* 定时器处理函数 */
static void timer_func(unsigned long arg) {int value = 0;struct mod_struct *dev = (struct mod_struct*)arg;value = gpio_get_value(dev->irqkey0.gpio_num);if(value == 0)   {          /* 按下 */atomic_set(&dev->keyvalue, dev->irqkey0.value);/*=0x01*/} else if(value == 1) {     /* 释放 */atomic_set(&dev->keyvalue, 0X80 | (dev->irqkey0.value));atomic_set(&dev->releasekey, 1);  /* 完成的按键过程 */}
}
/** @description	: 按键初始化函数* @param 		: dev* @return 		: 无*/
static int key_init(struct mod_struct *dev)
{int ret = 0;/* 1、获取设备节点：/devicetree-leds-pincrl */dev->nd = of_find_node_by_path("/devicetree-key0-interrupt");if(dev->nd == NULL) {printk("devicetree-key0-interrupt node not find!\r\n");ret = -EINVAL;goto fail_fd;} else {printk("devicetree-key0-interrupt node find!\r\n");}/* 2、从设备节点下的led-gpio属性里获取gpio编号 */dev->irqkey0.gpio_num = of_get_named_gpio(dev->nd,"key-gpio", 0);if(dev->irqkey0.gpio_num < 0) {printk("can't get key-gpio\r\n");ret = -EINVAL;goto fail_gpio;}printk("key-gpio num = %d\r\n", dev->irqkey0.gpio_num);/*3、申请gpio(检查是否被占用)*/sprintf(dev->irqkey0.name,"%s","key0-gpio-interrupt");ret = gpio_request(dev->irqkey0.gpio_num,dev->irqkey0.name);if(ret){ret = -EBUSY;printk("IO %d busy,can't request!\r\n",dev->irqkey0.gpio_num);goto fail_ioreq;}/*4、设置key0为输入 */ret = gpio_direction_input(dev->irqkey0.gpio_num);if(ret < 0) {printk("can't set gpio!\r\n");goto fail_ioset;}/*5、根据IO编号获取其中断号*/dev->irqkey0.irq_num=gpio_to_irq(dev->irqkey0.gpio_num);
#if 0dev->irqkey0.irq_num = irq_of_parse_and_map(dev->nd,0);
#endif/*6、设置中断函数*/dev->irqkey0.handler = key0_handler;dev->irqkey0.value  = KEY0VALUE;/*7、注册中断*/ret = request_irq(dev->irqkey0.irq_num,dev->irqkey0.handler,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,dev->irqkey0.name,&mod_device);if(ret){printk("irq %d request failed!\r\n", dev->irqkey0.irq_num);goto fail_irq;}tasklet_init(&dev->irqkey0.tasklet, key_tasklet, (unsigned long)dev);/*8、初始化定时器*/init_timer(&mod_device.timer);mod_device.timer.function = timer_func;return 0;
fail_irq:
fail_ioset:gpio_free(dev->irqkey0.gpio_num);
fail_ioreq:
fail_gpio:
fail_fd:return ret;
}
/** @description	: 驱动出口函数* @param 		: 无* @return 		: 无*/
static int __init key0_interrupt_init(void)
{int ret = 0;
/*一、 注册字符设备驱动 *//* 1、创建设备号 */if (mod_device.major){		mod_device.devid = MKDEV(mod_device.major,0);//设备号起始点(major,0)//设备号起始点开始，申请DeviceNodes个设备号ret = register_chrdev_region(mod_device.devid,DeviceNodes,DeviceName);} else {ret = alloc_chrdev_region(&mod_device.devid,0,DeviceNodes,DeviceName);	/* 申请设备号 */mod_device.major = MAJOR(mod_device.devid);	/* 获取分配号的主设备号 */mod_device.minor = MINOR(mod_device.devid);	/* 获取分配号的次设备号 */	}if(ret < 0){ printk("设备号申请失败\r\n");goto fail_chrdev; }printk("mod_device major=%d,minor=%d\r\n",mod_device.major,mod_device.minor);	/* 2、初始化cdev并添加cdev */mod_device.cdev.owner = THIS_MODULE;cdev_init(&mod_device.cdev,&beep_fops);ret = cdev_add(&mod_device.cdev,mod_device.devid,DeviceNodes);if(ret < 0){ printk("添加cdev失败！\r\n");goto fail_cdev; }/* 3、创建类 */mod_device.class = class_create(THIS_MODULE,DeviceName);if (IS_ERR(mod_device.class)) { ret = PTR_ERR(mod_device.class);goto fail_class; } /* 4、创建设备节点*/mod_device.device = device_create(mod_device.class,NULL,mod_device.devid,NULL,"DeviceName");if (IS_ERR(mod_device.device)) { ret = PTR_ERR(mod_device.device);goto fail_device; }/* 5、初始化IO */ret = key_init(&mod_device);if(ret < 0) {goto fail_keyinit;}/* 6、初始化原子变量 */atomic_set(&mod_device.keyvalue, INVAKEY);/*mod_device.keyvalue=INVAKEY*/atomic_set(&mod_device.releasekey, 0);/*mod_device.releasekey=0*/
/*X、模块加载失败处理部分*/
fail_keyinit:device_destroy(mod_device.class,mod_device.devid);
fail_device:	class_destroy(mod_device.class);
fail_class:	cdev_del(&mod_device.cdev);
fail_cdev:unregister_chrdev_region(mod_device.devid,DeviceNodes);
fail_chrdev:return ret;
}
/** @description	: 驱动出口函数* @param 		: 无* @return 		: 无*/
static void __exit key0_interrupt_exit(void)/*按照相反顺序注销*/
{/*1、释放中断*/free_irq(mod_device.irqkey0.irq_num, &mod_device);/*2、内核定定时器注销部分*/del_timer_sync(&mod_device.timer);/* 删除timer *//*3、LED设备注销部分*/gpio_free(mod_device.irqkey0.gpio_num);/*注销gpio*/		/*4、设备驱动注销部分*/			device_destroy(mod_device.class,mod_device.devid);/*注销设备节点*/class_destroy(mod_device.class);/*注销类*/cdev_del(&mod_device.cdev);/*注销cdev*/unregister_chrdev_region(mod_device.devid,DeviceNodes);/*注销chrdev*/
}
module_init(key0_interrupt_init);
module_exit(key0_interrupt_exit);
MODULE_LICENSE("GPL");

六、work方式实现下半部的驱动程序

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/string.h>
#include <linux/irq.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/interrupt.h>
#define DeviceName 		"devicetree-key0-interrupt-work" //设备驱动名称
#define DeviceNodes 	1 					  	 //设备节点个数
#define KEY_NUM 		0X01             
#define KEY0VALUE       0X01
#define INVAKEY         0XFF
struct irq_keydesc{int gpio_num;           /* io编号 */int irq_num;            /* 中断号 */unsigned char value;    /* 键值 */char name[25];          /* 名字 */irqreturn_t (*handler) (int, void *);  /* 中断处理函数 */struct tasklet_struct tasklet;
};
/* 定义一个设备结构体 */
struct mod_struct {dev_t devid;			     /* 设备号 */int major;				     /* 主设备号 */int minor;				     /* 次设备号 */struct cdev cdev;		     /* cdev */struct class *class;	  	 /* 类 */struct device *device;	 	 /* 设备 */struct device_node *nd;  	 /* 设备节点 */struct irq_keydesc irqkey0;  /* 按键中断 */struct timer_list timer;	 /* 内核定时器 */struct work_struct work;     /* 工作队列 */atomic_t keyvalue;			 /* 原子变量1->整形*/atomic_t releasekey;		 /* 原子变量2->整形*/
};
struct mod_struct mod_device;	 /* 定义一个设备 */
/** @description		: 打开设备* @param - inode 	: 传递给驱动的inode* @param - filp 	: 设备文件，file结构体有个叫做private_data的成员变量* 					  一般在open的时候将private_data指向设备结构体。* @return 			: 0 成功;其他 失败*/
static int key0_interrupt_open(struct inode *inode, struct file *filp)
{filp->private_data = &mod_device; /* 设置私有数据 */return 0;
}
/** @description		: 从设备读取数据 * @param - filp 	: 要打开的设备文件(文件描述符)* @param - buf 	: 返回给用户空间的数据缓冲区* @param - cnt 	: 要读取的数据长度* @param - offt 	: 相对于文件首地址的偏移* @return 			: 读取的字节数，如果为负值，表示读取失败*/
static ssize_t key0_interrupt_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{int ret = 0;unsigned char keyvalue;unsigned char releasekey;struct mod_struct *dev = filp->private_data;keyvalue = atomic_read(&dev->keyvalue);releasekey = atomic_read(&dev->releasekey);if(releasekey) {        /* 有效按键 */if(keyvalue & 0x80) {keyvalue &= ~0x80;ret = copy_to_user(buf, &keyvalue, sizeof(keyvalue));} else {goto data_error;}atomic_set(&dev->releasekey, 0); /* 按下标志清零 */} else {goto data_error;}return ret;data_error:return -EINVAL;
}
/** @description		: 向设备写数据 * @param - filp 	: 设备文件，表示打开的文件描述符* @param - buf 	: 要写给设备写入的数据* @param - cnt 	: 要写入的数据长度* @param - offt 	: 相对于文件首地址的偏移* @return 			: 写入的字节数，如果为负值，表示写入失败*/
static ssize_t key0_interrupt_write(struct file *filp, const char __user *buf,size_t cnt, loff_t *offt)
{return 0;
}
/** @description		: 关闭/释放设备* @param - filp 	: 要关闭的设备文件(文件描述符)* @return 			: 0 成功;其他 失败*/static int key0_interrupt_release(struct inode *inode, struct file *filp)
{return 0;
}
/* 设备操作函数 */
static struct file_operations beep_fops = {.owner    	=  THIS_MODULE,.open     	=  key0_interrupt_open,.read     	=  key0_interrupt_read,.write    	=  key0_interrupt_write,.release  	=  key0_interrupt_release,
};
/* 按键中断处理函数 */
static irqreturn_t key0_handler(int irq, void *dev_id)
{struct mod_struct *dev = dev_id;#if 0dev->timer.data = (volatile long)dev_id;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(20)); /* 20ms定时 */#endif//tasklet_schedule(&dev->irqkey0.tasklet);schedule_work(&dev->work);return IRQ_HANDLED;
}
/* tasklet (下半部方法1)*/
static void key_tasklet(unsigned long data)
{struct mod_struct *dev = (struct mod_struct*)data;dev->timer.data = data;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(20)); /* 20ms定时 */
}
/* work (下半部方法2)*/
static void key_work(struct work_struct *work)
{struct mod_struct *dev = container_of(work, struct mod_struct, work);dev->timer.data = (unsigned long)dev;mod_timer(&dev->timer, jiffies + msecs_to_jiffies(20)); /* 20ms定时 */ 
}
/* 定时器处理函数 */
static void timer_func(unsigned long arg) {int value = 0;struct mod_struct *dev = (struct mod_struct*)arg;value = gpio_get_value(dev->irqkey0.gpio_num);if(value == 0)   {          /* 按下 */atomic_set(&dev->keyvalue, dev->irqkey0.value);/*=0x01*/} else if(value == 1) {     /* 释放 */atomic_set(&dev->keyvalue, 0X80 | (dev->irqkey0.value));atomic_set(&dev->releasekey, 1);  /* 完成的按键过程 */}
}
/** @description	: 按键初始化函数* @param 		: dev* @return 		: 无*/
static int key_init(struct mod_struct *dev)
{int ret = 0;/* 1、获取设备节点：/devicetree-leds-pincrl */dev->nd = of_find_node_by_path("/devicetree-key0-interrupt");if(dev->nd == NULL) {printk("devicetree-key0-interrupt node not find!\r\n");ret = -EINVAL;goto fail_fd;} else {printk("devicetree-key0-interrupt node find!\r\n");}/* 2、从设备节点下的led-gpio属性里获取gpio编号 */dev->irqkey0.gpio_num = of_get_named_gpio(dev->nd,"key-gpio", 0);if(dev->irqkey0.gpio_num < 0) {printk("can't get key-gpio\r\n");ret = -EINVAL;goto fail_gpio;}printk("key-gpio num = %d\r\n", dev->irqkey0.gpio_num);/*3、申请gpio(检查是否被占用)*/sprintf(dev->irqkey0.name,"%s","key0-gpio-interrupt");ret = gpio_request(dev->irqkey0.gpio_num,dev->irqkey0.name);if(ret){ret = -EBUSY;printk("IO %d busy,can't request!\r\n",dev->irqkey0.gpio_num);goto fail_ioreq;}/*4、设置key0为输入 */ret = gpio_direction_input(dev->irqkey0.gpio_num);if(ret < 0) {printk("can't set gpio!\r\n");goto fail_ioset;}/*5、根据IO编号获取其中断号*/dev->irqkey0.irq_num=gpio_to_irq(dev->irqkey0.gpio_num);
#if 0dev->irqkey0.irq_num = irq_of_parse_and_map(dev->nd,0);
#endif/*6、设置中断函数*/dev->irqkey0.handler = key0_handler;dev->irqkey0.value  = KEY0VALUE;/*7、注册中断*/ret = request_irq(dev->irqkey0.irq_num,dev->irqkey0.handler,IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING,dev->irqkey0.name,&mod_device);if(ret){printk("irq %d request failed!\r\n", dev->irqkey0.irq_num);goto fail_irq;}INIT_WORK(&dev->work,key_work);//tasklet_init(&dev->irqkey0.tasklet, key_tasklet, (unsigned long)dev);/*8、初始化定时器*/init_timer(&mod_device.timer);mod_device.timer.function = timer_func;return 0;
fail_irq:
fail_ioset:gpio_free(dev->irqkey0.gpio_num);
fail_ioreq:
fail_gpio:
fail_fd:return ret;
}
/** @description	: 驱动出口函数* @param 		: 无* @return 		: 无*/
static int __init key0_interrupt_init(void)
{int ret = 0;
/*一、 注册字符设备驱动 *//* 1、创建设备号 */if (mod_device.major){		mod_device.devid = MKDEV(mod_device.major,0);//设备号起始点(major,0)//设备号起始点开始，申请DeviceNodes个设备号ret = register_chrdev_region(mod_device.devid,DeviceNodes,DeviceName);} else {ret = alloc_chrdev_region(&mod_device.devid,0,DeviceNodes,DeviceName);	/* 申请设备号 */mod_device.major = MAJOR(mod_device.devid);	/* 获取分配号的主设备号 */mod_device.minor = MINOR(mod_device.devid);	/* 获取分配号的次设备号 */	}if(ret < 0){ printk("设备号申请失败\r\n");goto fail_chrdev; }printk("mod_device major=%d,minor=%d\r\n",mod_device.major,mod_device.minor);	/* 2、初始化cdev并添加cdev */mod_device.cdev.owner = THIS_MODULE;cdev_init(&mod_device.cdev,&beep_fops);ret = cdev_add(&mod_device.cdev,mod_device.devid,DeviceNodes);if(ret < 0){ printk("添加cdev失败！\r\n");goto fail_cdev; }/* 3、创建类 */mod_device.class = class_create(THIS_MODULE,DeviceName);if (IS_ERR(mod_device.class)) { ret = PTR_ERR(mod_device.class);goto fail_class; } /* 4、创建设备节点*/mod_device.device = device_create(mod_device.class,NULL,mod_device.devid,NULL,"DeviceName");if (IS_ERR(mod_device.device)) { ret = PTR_ERR(mod_device.device);goto fail_device; }/* 5、初始化IO */ret = key_init(&mod_device);if(ret < 0) {goto fail_keyinit;}/* 6、初始化原子变量 */atomic_set(&mod_device.keyvalue, INVAKEY);/*mod_device.keyvalue=INVAKEY*/atomic_set(&mod_device.releasekey, 0);/*mod_device.releasekey=0*/
/*X、模块加载失败处理部分*/
fail_keyinit:device_destroy(mod_device.class,mod_device.devid);
fail_device:	class_destroy(mod_device.class);
fail_class:	cdev_del(&mod_device.cdev);
fail_cdev:unregister_chrdev_region(mod_device.devid,DeviceNodes);
fail_chrdev:return ret;
}
/** @description	: 驱动出口函数* @param 		: 无* @return 		: 无*/
static void __exit key0_interrupt_exit(void)/*按照相反顺序注销*/
{/*1、释放中断*/free_irq(mod_device.irqkey0.irq_num, &mod_device);/*2、内核定定时器注销部分*/del_timer_sync(&mod_device.timer);/* 删除timer *//*3、LED设备注销部分*/gpio_free(mod_device.irqkey0.gpio_num);/*注销gpio*/		/*4、设备驱动注销部分*/			device_destroy(mod_device.class,mod_device.devid);/*注销设备节点*/class_destroy(mod_device.class);/*注销类*/cdev_del(&mod_device.cdev);/*注销cdev*/unregister_chrdev_region(mod_device.devid,DeviceNodes);/*注销chrdev*/
}
module_init(key0_interrupt_init);
module_exit(key0_interrupt_exit);
MODULE_LICENSE("GPL");

七、APP测试程序

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
/**argc:应用程序参数个数*argv[]:具体的参数内容，字符串形式 *./imx6uirqAPP  <filename>  * ./imx6uirqAPP /dev/mx6uirq*/
int main(int argc, char *argv[])
{int fd, ret;char *filename;unsigned char data;if(argc != 2) {printf("Error Usage!\r\n");return -1;}filename = argv[1];fd = open(filename, O_RDWR);if(fd < 0) {printf("file %s open failed!\r\n", filename);return -1;}/* 循环读取 */while(1) {ret = read(fd, &data, sizeof(data));if(ret < 0) {	} else {if(data)printf("key value = %#x\r\n", data);}}close(fd);return 0;
}

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