1.linux内核中断子系统相关的API

解析中断的相关设备树节点信息

of_find_compatible_node

根据解析的中断信息获取软中断号

irq_of_parse_and_map(struct device_node *dev,int index)

参数：dev中断对应的设备树节点指针 index：当前中断 对应值的索引号

返回值：成功返回软中断号，失败返回0

注册中断

request_irq(unsigned int irq,irq_handler_t handler,unsigned long flags,const char *name,void *dev)

参数：irq：当前中断的软中断号

           handler：中断处理函数的函数指针

           flags:设置中断的触发方式

           name:当前中断名字

           dev:传递给中断处理程序的参数，也是当前中断对应的irqatction的key值

注销中断

void *free_irq(unsigned int irq,void *dev_id)

参数：

        irq：要注销的中断对应的软中断号

        dev_id:request_irq最后一个参数的数值，一定要写的和注册时的一样，不然会报错

6.中断底半部

中断顶半部：主要处理一些紧急，不耗时的任务

中断底半部：主要处理一些不紧急，耗时的任务

tasklet

tasklet机制是基于软中断实现的一种底半部的机制，但是相比较于软中断，tasklet没有最大数量的限制

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
int number = 0;
struct device_node *dnode;
unsigned int key_irqno[3];
struct cdev *cdev;
unsigned int major;
unsigned int minor;
dev_t devno;
unsigned int condition = 0;
struct class *cls;
struct device *dev;
// 定义等待队列头
wait_queue_head_t wq_head;
char kbuf[128] = {0};
struct device_node *dnode;
unsigned int gpiono;
int mycdev_open(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{// 将准备好的硬件数据拷贝到用户空间int ret = copy_to_user(ubuf, (void *)number, size);if (ret){printk("copy_to_user err\n");return ret;}return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
// 定义操作方法结构体遍历并且初始化
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,
};
irqreturn_t key_handler(int irq, void *dev)
{// 根据dev的数值的不同来区分不同的按键int which = (int)dev;switch (which){case 0:number = 0;if (gpio_get_value(gpiono))// 亮灯gpio_set_value(gpiono, 1);elsegpio_set_value(gpiono, 0);printk("key1 interrupt\n");break;case 1:number = 1;if (gpio_get_value(gpiono))// 亮灯gpio_set_value(gpiono, 1);elsegpio_set_value(gpiono, 0);printk("key2 interrupt\n");break;case 2:number = 2;if (gpio_get_value(gpiono))// 亮灯gpio_set_value(gpiono, 1);elsegpio_set_value(gpiono, 0);printk("key3 interrupt\n");break;default:break;}return IRQ_HANDLED;
}
static int __init mycdev_init(void)
{// 注册字符设备驱动major = register_chrdev(0, "MYchrdev", &fops);if (major < 0){printk("字符设备驱动注册失败\n");return major;}printk("字符设备驱动注册成功major=%d\n", major);// 向上提交目录信息cls = class_create(THIS_MODULE, "MYcdev");if (IS_ERR(cls)){printk("向上提交目录信息失败\n");return -PTR_ERR(cls);}printk("向上提交目录信息成功\n");// 向上提交设备信息dev = device_create(cls, NULL, MKDEV(major, 0), NULL, "MYcdev%d", 0);if (IS_ERR(dev)){printk("向上提交设备节点失败\n");return -PTR_ERR(cls);}printk("向上提交设备节点信息成功\n");// 通过设备树节点名字解析设备树结点dnode = of_find_compatible_node(NULL, NULL, "hqyj,myirq");if (dnode == NULL){printk("解析设备树节点信息失败\n");return -ENXIO;}printk("解析设备树节点信息成功\n");// 获取软中断号int i;for (i = 0; i < 3; i++){key_irqno[i] = irq_of_parse_and_map(dnode, i);if (!key_irqno[i]){printk("解析按键的设备树节点失败\n");return -ENXIO;}printk("解析按键的设备树节点成功\n");// 注册中断int ret;ret = request_irq(key_irqno[i], key_handler, IRQF_TRIGGER_FALLING, "key", (void *)i);if (ret < 0){printk("注册中断失败\n");return -1;}printk("注册中断成功\n");}// 解析LED设备树节点dnode = of_find_node_by_path("/leds");if (dnode == NULL){printk("解析设备树节点失败\n");return -ENXIO;}printk("解析设备树节点成功\n");// 获取GPIO编号gpiono = of_get_named_gpio(dnode, "led1-gpio", 0);if (gpiono < 0){printk("gpio编号解析失败\n");return -ENXIO;}printk("解析gpio编号成功%d\n", gpiono);// 申请gpio编号int ret;ret = gpio_request(gpiono, NULL);if (ret){printk("申请gpio编号失败\n");return -1;}printk("申请gpio编号成功\n");// 设置为输出模式gpio_direction_output(gpiono, 0);return 0;
}
static void __exit mycdev_exit(void)
{int i;for (i = 0; i < 3; i++)free_irq(key_irqno[i], (void *)i);gpio_free(gpiono);device_destroy(cls, MKDEV(major, i));// 销毁目录信息class_destroy(cls);// 字符设备驱动的注销unregister_chrdev(major, "MYchrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");