4412驱动-字符驱动之中断按键 forthdrvtest

4412 参考代码 点击打开链接

键盘扫描实验

中断按键

IRQF_TRIGGER_FALLING 代表下降沿触发

IRQF_TRIGGER_RISING    代表上升沿触发

驱动：

#include <linux/module.h>#include <linux/kernel.h>#include <linux/init.h>#include <linux/platform_device.h>#include <linux/fb.h>#include <linux/backlight.h>#include <linux/err.h>#include <linux/pwm.h>#include <linux/slab.h>#include <linux/miscdevice.h>#include <linux/delay.h>#include <linux/timer.h>  /*timer*/#include <asm/uaccess.h>  /*jiffies*/#include <linux/delay.h>#include <linux/interrupt.h> //request_irq#include <mach/irqs.h> //中断号，已包含plat/irqs.h#include <linux/fs.h>#include <linux/device.h> //class_create device_create#include <mach/regs-gpio.h>#include <linux/io.h> //ioremap ioread32 iowrite32#include <linux/sched.h>#include <linux/of.h>  #include <linux/of_device.h>  #include <linux/poll.h>#include <mach/gpio.h>#include <linux/gpio.h>#include <mach/gpio.h>#include <plat/gpio-cfg.h>static struct class *forthdrv_class;static struct class_device*forthdrv_class_dev;#if 0volatile unsigned long *gpfcon;volatile unsigned long *gpfdat;volatile unsigned long *gpgcon;volatile unsigned long *gpgdat;#endifstatic DECLARE_WAIT_QUEUE_HEAD(button_waitq);/* 中断事件标志, 中断服务程序将它置1，forth_drv_read将它清0 */static volatile int ev_press = 0;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] = {{EXYNOS4_GPX3(2), 0x01},{EXYNOS4_GPX3(3), 0x02},{EXYNOS4_GPX3(4), 0x03},{EXYNOS4_GPX3(5), 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;//比如输出一个高电平：gpio_set_value(EXYNOS4X12_GPM4(0),1);//得到输入的值：gpio_get_value(EXYNOS4X12_GPM3(0))?pinval = gpio_get_value(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 */return IRQ_RETVAL(IRQ_HANDLED);}static int forth_drv_open(struct inode *inode, struct file *file){int ret;ret = request_irq(IRQ_EINT(26), buttons_irq, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "k1", &pins_desc[0]);ret =request_irq(IRQ_EINT(27), buttons_irq, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "k2", &pins_desc[1]);ret =request_irq(IRQ_EINT(28), buttons_irq, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "k3", &pins_desc[2]);ret =request_irq(IRQ_EINT(29), buttons_irq, IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, "k4", &pins_desc[3]);if (ret < 0) {printk("request_irq faild\n");return -EINVAL;}return 0;}ssize_t forth_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 forth_drv_close(struct inode *inode, struct file *file){free_irq(IRQ_EINT(26), &pins_desc[0]);free_irq(IRQ_EINT(27), &pins_desc[1]);free_irq(IRQ_EINT(28), &pins_desc[2]);free_irq(IRQ_EINT(29), &pins_desc[3]);return 0;}static unsigned forth_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 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    =  forth_drv_open,     .read =forth_drv_read,   .release =  forth_drv_close,.poll    =  forth_drv_poll,};int major;static int forth_drv_init(void){major = register_chrdev(0, "forth_drv", &sencod_drv_fops);forthdrv_class = class_create(THIS_MODULE, "forth_drv");forthdrv_class_dev = device_create(forthdrv_class, NULL, MKDEV(major, 0), NULL, "mybuttons"); /* /dev/buttons */#if 0gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);gpfdat = gpfcon + 1;gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);gpgdat = gpgcon + 1;#endifreturn 0;}static void forth_drv_exit(void){unregister_chrdev(major, "forth_drv");device_destroy(forthdrv_class, MKDEV(major, 0));class_destroy(forthdrv_class);//iounmap(gpfcon);//iounmap(gpgcon);}module_init(forth_drv_init);module_exit(forth_drv_exit);MODULE_LICENSE("GPL");

应用：

#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdio.h>#include <poll.h>/* forthdrvtest   */int main(int argc, char **argv){int fd;unsigned char key_val;int ret;struct pollfd fds[1];fd = open("/dev/mybuttons", O_RDWR);if (fd < 0){printf("can't open!\n");}fds[0].fd     = fd;fds[0].events = POLLIN;while (1){ret = poll(fds, 1, 5000);if (ret == 0){printf("time out\n");}else{read(fd, &key_val, 1);printf("key_val = 0x%x\n", key_val);}}return 0;}