ckfwq/linux-3.0.4/drivers/misc/smoke.c

/*
 * smoke.c - driver for Gpio Test
 *						   8bits out, 4bits in
 *
 * Copyright (C) 2012 Loongson Corporation
 *
 * 2013-03-15
 */
#include <linux/miscdevice.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/rcupdate.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/completion.h>
#include <asm/io.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <asm/uaccess.h>
#include <linux/gpio.h>
#include <linux/time.h>

#define GPIOECHO   4


static int smoke_open(struct inode *inode, struct file *file) 
{
	//printk(KERN_ALERT"#####################sensor open ok!!!\n");

	gpio_request(GPIOECHO, "ECHO");

	gpio_direction_input(GPIOECHO);
	return 0;
}

static int smoke_close(struct inode *inode, struct file *file)
{
	gpio_free(GPIOECHO);
	//printk(KERN_ALERT"sensor close ok!!!\n");
	return 0;
}

static ssize_t smoke_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
{

	return 0;
}

static ssize_t smoke_write(struct file *file, const char __user *buf, size_t count, loff_t *ptr)
{
	return 0;
}


static int  get_data(void)
{
	return gpio_get_value(GPIOECHO);
}

static long smoke_ioctl( struct file *file, unsigned int cmd, unsigned long arg)
{
	int ret;
//	printk(KERN_ALERT"in ioctl func!");
	switch(cmd){
		case 0:
			{
			void __user *p = (void __user *)arg;
			ret = get_data();
			copy_to_user(p, &ret, sizeof(ret));
			}
			break;
		default:
			printk(KERN_ALERT"in ioctl default!\n");

	}

	return 0;
}

static const struct file_operations smoke_ops = {
		.owner = THIS_MODULE,
		.open = smoke_open,
		.release = smoke_close,
		.read = smoke_read,
		.write = smoke_write,
		.unlocked_ioctl = smoke_ioctl
};

static struct miscdevice smoke_miscdev = {
		MISC_DYNAMIC_MINOR,
		"smoke",
		&smoke_ops,
};

static int __init smoke_init(void)
{

	if (misc_register(&smoke_miscdev))
	{
	  printk(KERN_ALERT"###############: Couldn't register device 0, %d.\n", 255);
	  return -EBUSY;
	}

	return 0;
}

static void __exit smoke_exit(void)
{
	misc_deregister(&smoke_miscdev);
}

module_init(smoke_init);
module_exit(smoke_exit);
MODULE_LICENSE("GPL");