linux 中断号是什么意思

1 #include <linux/init.h>
  2 #include <linux/module.h>
  3 #include <linux/of.h>
  4 #include <linux/of_irq.h>
  5 #include <linux/interrupt.h>
  6 #include <linux/slab.h>
  7 #include <linux/fs.h>
  8 #include <linux/device.h>
  9 #include <linux/kdev_t.h>
 10 #include <linux/err.h>
 11 #include <linux/device.h>
 12 #include <asm/io.h>
 13 #include <asm/uaccess.h>
 14 
 15 
 16 #define GPXCON_REG 0X11000C20   //不可以从数据寄存器开始映射，要配置寄存器
 17 #define KEY_ENTER  28
 18 
 19 //0、设计一个描述按键的数据的对象
 20 struct key_event{
 21     int code;    //按键类型：home，esc,enter
 22     int value;   //表状态，按下，松开
 23 };
 24 
 25 //1、设计一个全局对象——— 描述key的信息
 26 struct key_desc{
 27     unsigned int dev_major;
 28     int irqno;  //中断号
 29     struct class  *cls;
 30     struct device *dev;
 31     void *reg_base;
 32     struct key_event event;
 33 };
 34 
 35 struct key_desc *key_dev;
 36 
 37 
 38 irqreturn_t key_irq_handler(int irqno, void *devid)
 39 {
 40     printk("----------%s---------",__FUNCTION__);
 41 
 42     int value;
 43     //读取按键状态
 44     value = readl(key_dev->reg_base + 4) & (0x01<<2);
 45     
 46     if(value){
 47         printk("key3 up\n");
 48         key_dev->event.code  = KEY_ENTER;
 49         key_dev->event.value = 0;
 50     }else{
 51         printk("key3 down\n");
 52         key_dev->event.code  = KEY_ENTER;
 53         key_dev->event.value = 1;
 54     }
 55     return IRQ_HANDLED;
 56 }
 57 
 58 
 59 //获取中断号
 60 int get_irqno_from_node(void)
 61 {
 62     int irqno;
 63     //获取设备树中的节点
 64     struct device_node *np = of_find_node_by_path("/key_int_node");
 65     if(np){
 66         printk("find node success\n");
 67     }else{
 68         printk("find node failed\n");
 69     }
 70 
 71     //通过节点去获取中断号
 72     irqno = irq_of_parse_and_map(np, 0);
 73     printk("iqrno = %d",key_dev->irqno);
 74 
 75     return irqno;
 76 }
 77 
 78 ssize_t key_drv_read (struct file * filp, char __user * buf, size_t count, loff_t * fops)
 79 {
 80     //printk("----------%s---------",__FUNCTION__);
 81     int ret;
 82     ret = copy_to_user(buf, &key_dev->event, count);
 83     if(ret > 0)
 84     {
 85         printk("copy_to_user error\n");
 86         return -EFAULT;
 87     }
 88 
 89     //传递给用户数据后，将数据清除,否则APP每次读都是第一次的数据
 90     memset(&key_dev->event, 0, sizeof(key_dev->event));
 91     return count;
 92 }
 93 
 94 ssize_t key_drv_write (struct file *filp, const char __user * buf, size_t count, loff_t * fops)
 95 {
 96     printk("----------%s---------",__FUNCTION__);
 97     return 0;
 98 }
 99 
100 int key_drv_open (struct inode * inode, struct file *filp)
101 {
102     printk("----------%s---------",__FUNCTION__);
103     return 0;
104 }
105 
106 int key_drv_close (struct inode *inode, struct file *filp)
107 {
108     printk("----------%s---------",__FUNCTION__);
109     return 0;
110 }
111 
112 
113 const struct file_operations key_fops = {
114     .open    = key_drv_open,
115     .read    = key_drv_read,
116     .write   = key_drv_write,
117     .release = key_drv_close,
118 
119 };
120 
121 
122 
123 static int __init key_drv_init(void)
124 {
125     //演示如何获取到中断号
126     int ret;
127     
128     //1、设定全局设备对象并分配空间
129     key_dev = kzalloc(sizeof(struct key_desc), GFP_KERNEL);  //GFP_KERNEL表正常分配内存
130                           //kzalloc相比于kmalloc，不仅分配连续空间，还会将内存初始化清零
131 
132     //2、动态申请设备号
133     key_dev->dev_major = register_chrdev(0, "key_drv", &key_fops);
134 
135     //3、创建设备节点文件
136     key_dev->cls = class_create(THIS_MODULE, "key_cls");
137     key_dev->dev = device_create(key_dev->cls, NULL, MKDEV(key_dev->dev_major, 0), NULL, "key0");
138 
139     //4、硬件初始化 -- 地址映射或中断申请    
140     
141     key_dev->reg_base = ioremap(GPXCON_REG,8);
142 
143     key_dev->irqno = get_irqno_from_node();
144     
145     ret = request_irq(key_dev->irqno, key_irq_handler, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, 
146         "key3_eint10", NULL);
147     if(ret != 0)
148     {
149         printk("request_irq error\n");
150         return ret;
151     }
152 
153     //a. 硬件如何获取数据
154     
155     
156     
157     return 0;
158 }
159 
160 static void __exit key_drv_exit(void)
161 {
162     iounmap(GPXCON_REG);
163     free_irq(key_dev->irqno, NULL);  //free_irq与request_irq的最后一个参数一致
164     device_destroy(key_dev->cls, MKDEV(key_dev->dev_major, 0));
165     class_destroy(key_dev->cls);
166     unregister_chrdev(key_dev->dev_major, "key_drv");
167     kfree(key_dev);
168 }
169 
170 
171 
172 module_init(key_drv_init);
173 module_exit(key_drv_exit);
174 
175 MODULE_LICENSE("GPL");
key_drv.c