企业网站设计与制作,农业网站源码带数据,福州鼓楼区建设局网站,网站没有内容可以备案吗在前面的博文中记录的都是应用层主动查询读取驱动按键状态。驱动可不可以在有信号之后#xff0c;主动上报通知应用层事件呢#xff1f;当然可以#xff0c;linux如此博大精深。我们使用异步通信机制#xff0c;signal的办法实现该功能。
所谓的异步#xff0c;就是进程可…在前面的博文中记录的都是应用层主动查询读取驱动按键状态。驱动可不可以在有信号之后主动上报通知应用层事件呢当然可以linux如此博大精深。我们使用异步通信机制signal的办法实现该功能。
所谓的异步就是进程可以在信号没到前干别的事情等到信号到来了进程就会被内核通知去做相应的信号操作。进程是不知道信号什么时候来的。 First of all,我们学习一下应用层是怎样使用signal的。不叨叨先贴代码。(show me the fucking code) 我们使用kill 信号编号值 PID 号来传递命令给这个应用程序。使用ps查看这个程序的PID号。 目标按下按键时驱动通知应用层程序
1应用程序注册信号处理函数
2驱动来主动发出信号
3发给应用层
4使用kill_fasync函数发出信号
那么我们的驱动程序跟应用程序该怎么写呢show me the fucking code: #include linux/module.h
#include linux/kernel.h
#include linux/fs.h
#include linux/init.h
#include linux/delay.h
#include linux/irq.h
#include asm/uaccess.h
#include asm/irq.h
#include asm/io.h
#include asm/arch/regs-gpio.h
#include asm/hardware.h
#include linux/poll.hstatic struct class *fifthdrv_class;
static struct class_device *fifthdrv_class_dev;volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;static DECLARE_WAIT_QUEUE_HEAD(button_waitq);/* 中断事件标志, 中断服务程序将它置1fifth_drv_read将它清0 */
static volatile int ev_press 0;static struct fasync_struct *button_async;struct pin_desc{unsigned int pin;unsigned int key_val;
};/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */
/* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;struct pin_desc pins_desc[4] {{S3C2410_GPF0, 0x01},{S3C2410_GPF2, 0x02},{S3C2410_GPG3, 0x03},{S3C2410_GPG11, 0x04},
};/** 确定按键值*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{struct pin_desc * pindesc (struct pin_desc *)dev_id;unsigned int pinval;pinval s3c2410_gpio_getpin(pindesc-pin);if (pinval){/* 松开 */key_val 0x80 | pindesc-key_val;}else{/* 按下 */key_val pindesc-key_val;}ev_press 1; /* 表示中断发生了 */wake_up_interruptible(button_waitq); /* 唤醒休眠的进程 */kill_fasync (button_async, SIGIO, POLL_IN);return IRQ_RETVAL(IRQ_HANDLED);
}static int fifth_drv_open(struct inode *inode, struct file *file)
{/* 配置GPF0,2为输入引脚 *//* 配置GPG3,11为输入引脚 */request_irq(IRQ_EINT0, buttons_irq, IRQT_BOTHEDGE, S2, pins_desc[0]);request_irq(IRQ_EINT2, buttons_irq, IRQT_BOTHEDGE, S3, pins_desc[1]);request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, S4, pins_desc[2]);request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, S5, pins_desc[3]); return 0;
}ssize_t fifth_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{if (size ! 1)return -EINVAL;/* 如果没有按键动作, 休眠 */wait_event_interruptible(button_waitq, ev_press);/* 如果有按键动作, 返回键值 */copy_to_user(buf, key_val, 1);ev_press 0;return 1;
}int fifth_drv_close(struct inode *inode, struct file *file)
{free_irq(IRQ_EINT0, pins_desc[0]);free_irq(IRQ_EINT2, pins_desc[1]);free_irq(IRQ_EINT11, pins_desc[2]);free_irq(IRQ_EINT19, pins_desc[3]); fifth_drv_fasync (-1,filp,0);
return 0;}static unsigned fifth_drv_poll(struct file *file, poll_table *wait){unsigned int mask 0;poll_wait(file, button_waitq, wait); // 不会立即休眠if (ev_press)mask | POLLIN | POLLRDNORM;return mask;}static int fifth_drv_fasync (int fd, struct file *filp, int on){printk(driver: fifth_drv_fasync\n);return fasync_helper (fd, filp, on, button_async);}static struct file_operations sencod_drv_fops { .owner THIS_MODULE, /* 这是一个宏推向编译模块时自动创建的__this_module变量 */ .open fifth_drv_open, .read fifth_drv_read, .release fifth_drv_close,.poll fifth_drv_poll,.fasync fifth_drv_fasync,};int major;static int fifth_drv_init(void){major register_chrdev(0, fifth_drv, sencod_drv_fops);fifthdrv_class class_create(THIS_MODULE, fifth_drv);fifthdrv_class_dev class_device_create(fifthdrv_class, NULL, MKDEV(major, 0), NULL, buttons); /* /dev/buttons */gpfcon (volatile unsigned long *)ioremap(0x56000050, 16);gpfdat gpfcon 1;gpgcon (volatile unsigned long *)ioremap(0x56000060, 16);gpgdat gpgcon 1;return 0;}static void fifth_drv_exit(void){unregister_chrdev(major, fifth_drv);class_device_unregister(fifthdrv_class_dev);class_destroy(fifthdrv_class);iounmap(gpfcon);iounmap(gpgcon);return 0;}module_init(fifth_drv_init);module_exit(fifth_drv_exit);MODULE_LICENSE(GPL); ----------------------------------------------------------我-是漂亮的分割线------------------------------------------------------------------------------------------------------------------------------ #include sys/types.h
#include sys/stat.h
#include fcntl.h
#include stdio.h
#include poll.h
#include signal.h
#include sys/types.h
#include unistd.h
#include fcntl.h/* sixthdrvtest */
int fd;void my_signal_fun(int signum)
{unsigned char key_val;read(fd, key_val, 1);printf(key_val: 0x%x\n, key_val);
}int main(int argc, char **argv)
{unsigned char key_val;int ret;int Oflags;//signal(SIGIO, my_signal_fun);fd open(/dev/buttons, O_RDWR | O_NONBLOCK);if (fd 0){printf(cant open!\n);return -1;}fcntl(fd, F_SETOWN, getpid());Oflags fcntl(fd, F_GETFL); fcntl(fd, F_SETFL, Oflags | FASYNC);while (1){sleep(1000);}return 0;
}
