Linux驱动——混杂设备实现对蜂鸣器的操作

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

#define DEV_MINOR 0
#define DEV_CNT 1
#define DEV_DATA_SIZE 127
#define BEEP_ON _IO('i', 0)
#define BEEP_OFF _IO('i', 1)

void __iomem * base_gpioc = NULL;

char data[DEV_DATA_SIZE + 1] = {0};

ssize_t myread (struct file * fp, char __user * buf, size_t size, loff_t * offset)
{
	int ret;
	printk("enter myreadn");
	if(size > DEV_DATA_SIZE) {
		size = DEV_DATA_SIZE;
	}

	ret = copy_to_user(buf, data, size);
	if(ret) {
		printk("copy to user error.n");
		return -EFAULT;
	}
	return 0;
}

int myrelease (struct inode * pnode, struct file * fp)
{
	printk("enter myreleasen");
	return 0;
}


int myopen (struct inode * pnode, struct file * fp)
{
	printk("enter myopenn");
	return 0;
}
ssize_t mywrite (struct file * fp, const char __user *buf, size_t size, loff_t *offset)
{
	int ret;
	printk("enter writen");
	if(size > 127) {
		printk("size is invalid.n");
		return -ENOMEM;
	}
	ret = copy_from_user(data, buf, size);
	if(ret) {
		printk("copy from user error.n");
		return -EFAULT;
	}
	return 0;
}

long myioctl (struct file * fp, unsigned int cmd, unsigned long data)
{
	switch(cmd) {
		case BEEP_ON:
			iowrite32(ioread32(base_gpioc)|(0x01<<14), base_gpioc);
			break;
		case BEEP_OFF:
			iowrite32(ioread32(base_gpioc)&~(0x01<<14), base_gpioc);
			break;
		default:
			printk("invalid input.n");
			break;
	}
	return 0;
}

const struct file_operations beep_fops = {
	.owner = THIS_MODULE,
	.open = myopen,
	.read = myread,
	.write = mywrite,
	.unlocked_ioctl = myioctl,
	};
struct miscdevice beep_dev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "beep",
	.fops = &beep_fops
	};

int beep_init(void)
{
	int ret;
	ret = misc_register(&beep_dev);
	if(ret<0) {
		printk("misc register failed!n");
		goto misc_retister_fail;
	}

	base_gpioc = ioremap(PHY_baseADDR_GPIOC, SZ_64);
	if(IS_ERR_OR_NULL(base_gpioc)) {
		printk("ioremap error.n");
		goto ioremap_fail;
	}

	iowrite32((ioread32(base_gpioc+0x20)&~(0x03<<28))|(0x01<<28), base_gpioc + 0x20);
	iowrite32(ioread32(base_gpioc+0x04)|(0x01<<14), base_gpioc+0x04);
	iowrite32(ioread32(base_gpioc)&~(0x01<<14), base_gpioc);

	printk("beep dev driver init completed.n");
	return 0;

ioremap_fail:
	misc_deregister(&beep_dev);
misc_retister_fail:
	return -1;
}

kobject_create_and_add(const char * name, struct kobject * parent)

void beep_exit(void)
{
	iounmap(base_gpioc);
	misc_deregister(&beep_dev);
	printk("device unregister completed.n");
}
module_init(beep_init);
module_exit(beep_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David-Woo");
MODULE_DEscriptION("char device driver example");