2 * Copyright (C) 2010 Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19 #include <linux/module.h>
21 #include <linux/cdev.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24 #include <linux/interrupt.h>
26 MODULE_LICENSE("GPL");
29 static struct cdev *dev;
30 static const char def_greeting[] = "Hello, World!\n";
32 static DEFINE_SPINLOCK(hello_lock);
34 static int hello_open(struct inode *ino, struct file *fp)
39 static void hello_world(unsigned long greeting)
41 printk(KERN_INFO "%s", (char *) greeting);
44 static DECLARE_TASKLET(hello_tasklet, hello_world, def_greeting);
46 static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
49 printk(KERN_INFO "Scheduling tasklet...\n");
50 tasklet_schedule(&hello_tasklet);
54 static ssize_t hello_write(struct file *fp, const char __user *buf, size_t sz,
60 static int hello_release(struct inode *ino, struct file *fp)
65 static const struct file_operations hello_fops = {
68 .release = hello_release,
73 static int __init ch_init(void)
76 r = alloc_chrdev_region(&devnum, 0, 256, "hello");
84 dev->ops = &hello_fops;
85 r = cdev_add(dev, devnum, 256);
88 printk(KERN_DEBUG "Allocate major %d\n", MAJOR(devnum));
93 unregister_chrdev_region(devnum, 256);
98 static void __exit ch_exit(void)
100 tasklet_kill(&hello_tasklet);
102 unregister_chrdev_region(devnum, 256);
105 module_init(ch_init);
106 module_exit(ch_exit);