字符设备驱动之Buttons-中断上下部（工作队列-workqueue）
2011-09-16 19:15
399 查看
buttons.c
| #include <linux/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/cdev.h> #include <linux/ioport.h> #include <linux/pci.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/irq.h> #include <linux/interrupt.h> #include <asm/mach/irq.h> #include <asm/arch/regs-gpio.h> #include <linux/poll.h> #include <linux/delay.h> /* for udelay() */ #include <linux/time.h> #include <asm/delay.h> /* for udelay() */ static int major = 0; static struct class *cls; /* gpecon 0x56000040 */ /* gpfcon 0x56000050 */ /* gpgcon 0x56000060 */ static volatile unsigned long *gpecon; static volatile unsigned long *gpedat; static volatile unsigned long *gpfcon; static volatile unsigned long *gpfdat; static volatile unsigned long *gpgcon; static volatile unsigned long *gpgdat; struct key_desc { int irq; int pin; char *name; char key_val; int irq_pin_val; }; struct key_desc key_desc[] = { {IRQ_EINT0, S3C2410_GPF0, "K10", 1}, /* 松开: 1, 按下: 0x81 */ {IRQ_EINT2, S3C2410_GPF2, "K7", 2}, /* 松开: 2, 按下: 0x82 */ {IRQ_EINT11, S3C2410_GPG3, "K4", 3}, /* 松开: 3, 按下: 0x83 */ {IRQ_EINT19, S3C2410_GPG11, "K1", 4}, /* 松开: 4, 按下: 0x84 */ }; volatile char key = 0; static wait_queue_head_t button_waitq; #define BUF_LEN 10 static char key_buf[BUF_LEN]; static volatile int r = 0, w = 0; struct fasync_struct *buttons_async; static struct timer_list buttons_timer; struct key_desc *cur_kd; static int isEmpty(void) { return (r == w); } static int isFull(void) { return (r == ((w+1)%BUF_LEN)); } static int putData(char val) { if (isFull()) { return -1; } else { key_buf[w] = val; w = (w+1)%BUF_LEN; return 0; } } static int getData(char *p) { if (isEmpty()) { return -1; } else { *p = key_buf[r]; r = (r+1)%BUF_LEN; return 0; } } /*内核会在适当时候来调用这个处理函数*/ void buttons_work_func(struct work_struct *work) { /*具体事情，根据实际情况去定*/ int i; static int cnt = 0; int pre_jiffies, after_jiffies; printk("enter buttons_work_func: %d\n", cnt++); printk("task %s pid = %d\n", current->comm, current->pid); pre_jiffies = jiffies; for (i = 0; i < 10000; i++) udelay(1000); /* 10 s*/ //printk("after jiffies = %d\n", jiffies); after_jiffies = jiffies; printk("two jiffies = %d, %d, sub: %d\n", pre_jiffies, after_jiffies, after_jiffies-pre_jiffies); } /*定义一个工作队列*/ static struct work_struct buttons_work; static irqreturn_t buttons_irq(int irq, void *dev_id) { /* 执行上半部 */ static int cnt = 0; cur_kd = (struct key_desc *)dev_id; cur_kd->irq_pin_val = s3c2410_gpio_getpin(cur_kd->pin); printk("enter buttons_irq: %d\n", cnt++); mod_timer(&buttons_timer, jiffies+5); /*加载到内和链表，告诉内核*/ schedule_work(&buttons_work); return IRQ_HANDLED; } static void buttons_timer_function(unsigned long data) { /* 确定按键: 哪个按键,按下还是松开 */ // for (i = 0; i < 10000; i++); /* 浪费CPU */ /* 启动一个定时器: * 两要素: * 1. 时间 * 2. 处理函数 */ char key; int up; if (!cur_kd) { return; } up = s3c2410_gpio_getpin(cur_kd->pin); // gpfdat, gpgdat if (up != cur_kd->irq_pin_val) { return; } if (up) { key = cur_kd->key_val; } else { key = cur_kd->key_val | 0x80; } // printk("key = 0x%x\n", key); putData(key); /* 唤醒应用程序 */ wake_up_interruptible(&button_waitq); kill_fasync(&buttons_async, SIGIO, POLL_IN); //printk("buttons_irq current %s , pid = %d \n", current->comm, current->pid); } //static atomic_t button_can_open = ATOMIC_INIT(1); static DECLARE_MUTEX(button_sem); int buttons_open(struct inode *inode, struct file *file) { int i; unsigned long flags; if (file->f_flags & O_NONBLOCK) { if (down_trylock(&button_sem)) return -EBUSY; } else { down(&button_sem); } /* 如果之前没有程序获取信号量, 则成功 * 否则, 休眠 */ /* 注册中断 */ for (i = 0; i < 4; i++) { request_irq(key_desc[i].irq, buttons_irq, IRQF_SHARED | IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, key_desc[i].name, &key_desc[i]); } /* 设置GPIO为中断引脚 * 设置触发方式 * 使能中断 */ /* 设置KSCAN0(GPE11)为输出引脚,输出0 */ *gpecon &= ~(0x3 << 22); *gpecon |= (1 << 22); *gpedat &= ~(1<<11); return 0; } ssize_t buttons_read(struct file *file, char __user *buf, size_t size, loff_t *offset) { /* 如果没有按键发生, 休眠 */ /* key 等于 0, 才会休眠 * key 非0, 不会休眠 */ // command //printk("current %s , pid = %d before sleep\n", current->comm, current->pid); char key; if (isEmpty() && (file->f_flags & O_NONBLOCK)) return -EAGAIN; wait_event_interruptible(button_waitq, !isEmpty()); //printk("current %s , pid = %d after sleep\n", current->comm, current->pid); /* 被唤醒后, 把按键值返回给用户程序 */ getData(&key); copy_to_user(buf, &key, 1); /* 发生了中断, key=xxx */ //key = 0; return 1; } int buttons_close(struct inode *inode, struct file *file) { int i; for (i = 0; i < 4; i++) { free_irq(key_desc[i].irq, &key_desc[i]); } /* 释放信号量, 并唤醒在等待这个信号量的进程 */ up(&button_sem); return 0; } static unsigned int buttons_poll(struct file *file, struct poll_table_struct *wait) { static int cnt = 0; printk("buttons_poll cnt = %d\n", cnt++); poll_wait(file, &button_waitq, wait); /* 不会休眠, 只是挂入队列 */ return isEmpty()? 0 : POLLIN | POLLRDNORM; } static int buttons_fasync(int fd, struct file *filp, int on) { int retval; retval = fasync_helper(fd, filp, on, &buttons_async); if (retval < 0) return retval; return 0; } static const struct file_operations buttons_fops = { .owner = THIS_MODULE, .read = buttons_read, .open = buttons_open, /* 设置引脚,申请资源 */ .release = buttons_close, .poll = buttons_poll, .fasync = buttons_fasync, }; int buttons_init(void) { int i; major = register_chrdev(0, "buttons", &buttons_fops); /* sysfs ==> 挂接到/sys */ cls = class_create(THIS_MODULE, "buttons_class"); class_device_create(cls, NULL, MKDEV(major, 0), NULL, "buttons"); // mdev会根据/sys下的这些内容创建/dev/buttons gpecon = ioremap(0x56000040, 4096); gpedat = gpecon + 1; gpfcon = gpecon + 4; gpfdat = gpfcon + 1; gpgcon = gpecon + 8; gpgdat = gpgcon + 1; init_waitqueue_head(&button_waitq); init_timer(&buttons_timer); buttons_timer.function = buttons_timer_function; buttons_timer.expires = 0; add_timer(&buttons_timer); /*初始化我们的工作队列*/ INIT_WORK(&buttons_work, buttons_work_func); return 0; } void buttons_exit(void) { unregister_chrdev(major, "buttons"); class_device_destroy(cls, MKDEV(major, 0)); class_destroy(cls); iounmap(gpecon); del_timer(&buttons_timer); } module_init(buttons_init); module_exit(buttons_exit); MODULE_LICENSE("GPL"); |
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
相关文章推荐
- 字符设备驱动之Buttons-中断上下部（tasklet）
- 字符设备驱动之Buttons-循环缓冲队列+非阻塞访问
- 字符设备驱动之笔记-中断上下部
- 字符设备驱动之Buttons-中断
- 按键驱动程序设计---混杂设备、中断分层处理、工作队列、阻塞型驱动
- 字符设备驱动之Buttons-等待队列
- 字符设备驱动之Buttons-循环缓冲队列
- 中断处理的tasklet（小任务）机制和workqueue(工作队列)机制
- linux 触摸屏驱动中断下半部实现-工作队列
- 驱动之字符设备----按键中断
- Linux驱动开发-中断分层机制_工作队列 笔记 7
- 字符设备驱动之笔记-中断处理过程情景分析
- 字符设备驱动-----按键驱动（中断+poll机制）
- 第12课第4.3节 字符设备驱动程序之中断方式的按键驱动_编写代码
- Linux学习二， 中断编程和字符设备驱动
- arm 驱动基础：字符设备中断实现过程（内核->驱动->应用）
- 字符设备驱动笔记——中断方式按键驱动之linux中断处理结构（五）
- linux驱动开发之输入子系统编程（一）使用工作队列实现中断下半部
- 高级字符设备驱动--中断下半部机制之workqueue（二）
- 中断处理的tasklet（小任务）机制和workqueue(工作队列)机制