初入android驱动开发之字符设备(四-中断)

dev_id: 传给中断处理函数的參数。

2.简单的实例：

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/input.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <mach/gpio.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <linux/delay.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/wait.h>
#include <linux/sched.h>

#include <plat/gpio-core.h>
#include <plat/gpio-cfg.h>
#include <plat/gpio-cfg-helpers.h>

static struct class *buttondrv_class;
static struct device *buttondrv_class_dev;
int major;
volatile unsigned long *GPCCON;
volatile unsigned long *GPCDAT;
//static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
static unsigned char key_val;
static volatile int ev_press = 0;
struct pin_desc{
	unsigned int pin;
	unsigned int key_val;
};
struct pin_desc pins_desc[2] = {
	{S5PV210_GPH3(7), 0x01},
};
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
	printk(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>buttons_irq\n");
	struct pin_desc *pindesc = (struct pin_desc *)dev_id;
	unsigned int pinval;
	
	pinval = gpio_get_value(pindesc->pin);
	printk("irq >>>>>>>>>>>>>>>>>>>>>>>>>>>>pinval =%d \n",pinval);
	if (pinval)
	{	
		key_val = 0x80 | pindesc->key_val;
		printk("1111 >>>>>>>>>>>>>>>>>>>>>>>>>>>key_val =%d \n",key_val);
	}
	else
	{
		key_val = pindesc->key_val;
		printk("0000 >>>>>>>>>>>>>>>>>>>>>>>>>>>key_val =%d \n",key_val);
		
	}
    ev_press = 1;               
//    wake_up_interruptible(&button_waitq);  
	return IRQ_RETVAL(IRQ_HANDLED);
}

static int button_drv_open(struct inode *inode, struct file *file)
{
	printk(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>button_drv_open\n");
	int ret=-1;
	s3c_gpio_setpull(S5PV210_GPH3(7), S3C_GPIO_PULL_NONE);
	ret = request_threaded_irq(gpio_to_irq(S5PV210_GPH3(7)), NULL,
					buttons_irq,
					IRQF_TRIGGER_RISING,
					"s2", &pins_desc[0]);
	printk("ret=%d irq=%d >>>>>>>>>>>>>>>>>>>>>>>>>\n ",ret,gpio_to_irq(S5PV210_GPH3(7)));
	return 0;
}

int button_drv_close(struct inode *inode, struct file *file)
{
	free_irq(gpio_to_irq(S5PV210_GPH3(7)), &pins_desc[0]);
	return 0;
}

static int button_drv_read(struct file *filp, char __user *buf, 
                                         size_t count, loff_t *offp)
{
	printk(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>button_drv_read\n");
	if (count != 1)
		return -EINVAL;
	printk("read >>>>>>>>>>>>>>>>>>>>>>>>>>>key_val =%d \n",key_val);
//	wait_event_interruptible(button_waitq, ev_press);
	copy_to_user(buf, &key_val, 1);
	key_val=0;
	ev_press = 0;
	return 1;

}

static struct file_operations button_drv_fops = {
    .owner  =   THIS_MODULE,   
    .open   =   button_drv_open,       
    .read	=	button_drv_read,
    .release =  button_drv_close,
};

static int button_drv_init(void){
	printk(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>button_drv_init\n");

    GPCCON = (volatile unsigned long *)ioremap(0xE0200C60, 8);
	GPCDAT= GPCCON + 1;
	if (!GPCCON) {
		return -EIO;
	}
	major = register_chrdev(0, "button_drv", &button_drv_fops); 
	buttondrv_class = class_create(THIS_MODULE, "buttondrv");
	buttondrv_class_dev = device_create(buttondrv_class, NULL, MKDEV(major, 0), NULL, "button"); 
	return 0;
}

static void button_drv_exit(void){
	printk(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>button_drv_exit\n");	
	unregister_chrdev(major, "button_drv"); 
	device_unregister(buttondrv_class_dev);
	class_destroy(buttondrv_class);
	iounmap(GPCCON);

}

module_init(button_drv_init);
module_exit(button_drv_exit);
MODULE_LICENSE("GPL");