Linux 外部中断例子(一)

Linux 外部中断例子代码：

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#include
#include

#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))

struct fpga_key_dev
{
struct cdev cdev;
dev_t devno;
char test[20];
struct class *fpga_key_class;
struct fasync_struct *async_queue;

int message_cdev_open;
};

irqreturn_t irq_handler(int irqno, void *dev_id)

{
printk("fpga key down\n");

return IRQ_HANDLED;
}

static int fpga_key_open(struct inode *node, struct file *fd)
{
struct fpga_key_dev *dev;

printk("fpga_key_open()++\n");

printk("node->i_cdev = %x\n", (unsigned int)node->i_cdev);
dev = container_of(node->i_cdev, struct fpga_key_dev, cdev);
printk("dev->cdev = %x\n", (unsigned int)&dev->cdev);
printk("dev = %x\n", (unsigned int)dev);

if (!dev->message_cdev_open) {
dev->message_cdev_open = 1;
fd->private_data = dev;
}
else{
return -EFAULT;
}

printk("test[20] = %s\n",dev->test);

printk("fpga_key_open()--\n");

return 0;
}

static ssize_t fpga_key_write(struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
{
char temp_buffer [20];
int print_size = 0;
struct fpga_key_dev *dev = fd->private_data;

printk("fpga_key_wirte()++\n");
if(len > 20)
print_size = 20;
else
print_size = len;
printk("print_size = %d; len = %d\n", print_size, len);
if(copy_from_user(temp_buffer, buf, print_size))
return -EFAULT;

if (dev->async_queue)
kill_fasync(&dev->async_queue, SIGIO, POLL_IN);

printk("writing data:%s", temp_buffer);

printk("fpga_key_wirte()--\n");

return print_size;
}
static ssize_t fpga_key_read(struct file *fd, char __user *buf, size_t len, loff_t *ptr)
{
char *temp_buffer = "Hello fpga_key_read !\n";
int print_size = 0;

printk("fpga_key_read()++\n");

if(len > strnlen(temp_buffer,20))
print_size = strnlen(temp_buffer,20);
else
print_size = len;
printk("print_size = %d; len = %d\n", print_size, len);
if(copy_to_user(buf, temp_buffer, print_size))
return -EFAULT;
printk("%s", temp_buffer);
printk("fpga_key_read()--\n");

return print_size;
}

static int fpga_key_fasync(int fd, struct file *filp, int mode)
{
struct fpga_key_dev *dev = filp->private_data;

printk("fpga_key_fasync()++\n");

fasync_helper(fd, filp, mode, &dev->async_queue);

printk("fpga_key_fasync()--\n");

return 0;
}

static int fpga_key_release(struct inode *node, struct file *fd)
{
struct fpga_key_dev *dev = fd->private_data;

printk("fpga_key_release()++\n");

dev->message_cdev_open = 0;
fpga_key_fasync(-1, fd, 0);

printk("fpga_key_release()--\n");
return 0;
}

struct file_operations meassage_operatons =
{
.owner = THIS_MODULE,
.open = fpga_key_open,
.write = fpga_key_write,
.read = fpga_key_read,
.fasync = fpga_key_fasync,
.release = fpga_key_release,
};

struct fpga_key_dev fpga_key_dev;
static int __init fpga_key_init(void)
{
struct fpga_key_dev * dev;
char * temp_char = "hello world\n";
int ret = 0;
int inter = 0;

printk("fpga_key_to_app_init(void)++\n");

dev = &fpga_key_dev;
strcpy(dev->test, temp_char);;

alloc_chrdev_region(&dev->devno, 0, 1, "fpga_key_to_app");
cdev_init(&dev->cdev, &meassage_operatons);
cdev_add(&dev->cdev, dev->devno, 1