[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / drivers / hid / hid-roccat.c

/*
 * Roccat driver for Linux
 *
 * Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net>
 */

/*
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

/*
 * Module roccat is a char device used to report special events of roccat
 * hardware to userland. These events include requests for on-screen-display of
 * profile or dpi settings or requests for execution of macro sequences that are
 * not stored in device. The information in these events depends on hid device
 * implementation and contains data that is not available in a single hid event
 * or else hidraw could have been used.
 * It is inspired by hidraw, but uses only one circular buffer for all readers.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/sched.h>

#include "hid-roccat.h"

#define ROCCAT_FIRST_MINOR 0
#define ROCCAT_MAX_DEVICES 8

/* should be a power of 2 for performance reason */
#define ROCCAT_CBUF_SIZE 16

struct roccat_report {
	uint8_t *value;
	int len;
};

struct roccat_device {
	unsigned int minor;
	int open;
	int exist;
	wait_queue_head_t wait;
	struct device *dev;
	struct hid_device *hid;
	struct list_head readers;
	/* protects modifications of readers list */
	struct mutex readers_lock;

	/*
	 * circular_buffer has one writer and multiple readers with their own
	 * read pointers
	 */
	struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
	int cbuf_end;
	struct mutex cbuf_lock;
};

struct roccat_reader {
	struct list_head node;
	struct roccat_device *device;
	int cbuf_start;
};

static int roccat_major;
static struct class *roccat_class;
static struct cdev roccat_cdev;

static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
/* protects modifications of devices array */
static DEFINE_MUTEX(devices_lock);

static ssize_t roccat_read(struct file *file, char __user *buffer,
		size_t count, loff_t *ppos)
{
	struct roccat_reader *reader = file->private_data;
	struct roccat_device *device = reader->device;
	struct roccat_report *report;
	ssize_t retval = 0, len;
	DECLARE_WAITQUEUE(wait, current);

	mutex_lock(&device->cbuf_lock);

	/* no data? */
	if (reader->cbuf_start == device->cbuf_end) {
		add_wait_queue(&device->wait, &wait);
		set_current_state(TASK_INTERRUPTIBLE);

		/* wait for data */
		while (reader->cbuf_start == device->cbuf_end) {
			if (file->f_flags & O_NONBLOCK) {
				retval = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				retval = -ERESTARTSYS;
				break;
			}
			if (!device->exist) {
				retval = -EIO;
				break;
			}

			mutex_unlock(&device->cbuf_lock);
			schedule();
			mutex_lock(&device->cbuf_lock);
			set_current_state(TASK_INTERRUPTIBLE);
		}

		set_current_state(TASK_RUNNING);
		remove_wait_queue(&device->wait, &wait);
	}

	/* here we either have data or a reason to return if retval is set */
	if (retval)
		goto exit_unlock;

	report = &device->cbuf[reader->cbuf_start];
	/*
	 * If report is larger than requested amount of data, rest of report
	 * is lost!
	 */
	len = report->len > count ? count : report->len;

	if (copy_to_user(buffer, report->value, len)) {
		retval = -EFAULT;
		goto exit_unlock;
	}
	retval += len;
	reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;

exit_unlock:
	mutex_unlock(&device->cbuf_lock);
	return retval;
}

static unsigned int roccat_poll(struct file *file, poll_table *wait)
{
	struct roccat_reader *reader = file->private_data;
	poll_wait(file, &reader->device->wait, wait);
	if (reader->cbuf_start != reader->device->cbuf_end)
		return POLLIN | POLLRDNORM;
	if (!reader->device->exist)
		return POLLERR | POLLHUP;
	return 0;
}

static int roccat_open(struct inode *inode, struct file *file)
{
	unsigned int minor = iminor(inode);
	struct roccat_reader *reader;
	struct roccat_device *device;
	int error = 0;

	reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
	if (!reader)
		return -ENOMEM;

	mutex_lock(&devices_lock);

	device = devices[minor];

	mutex_lock(&device->readers_lock);

	if (!device) {
		pr_emerg("roccat device with minor %d doesn't exist\n", minor);
		error = -ENODEV;
		goto exit_err;
	}

	if (!device->open++) {
		/* power on device on adding first reader */
		error = hid_hw_power(device->hid, PM_HINT_FULLON);
		if (error < 0) {
			--device->open;
			goto exit_err;
		}

		error = hid_hw_open(device->hid);
		if (error < 0) {
			hid_hw_power(device->hid, PM_HINT_NORMAL);
			--device->open;
			goto exit_err;
		}
	}

	reader->device = device;
	/* new reader doesn't get old events */
	reader->cbuf_start = device->cbuf_end;

	list_add_tail(&reader->node, &device->readers);
	file->private_data = reader;

exit_unlock:
	mutex_unlock(&device->readers_lock);
	mutex_unlock(&devices_lock);
	return error;
exit_err:
	kfree(reader);
	goto exit_unlock;
}

static int roccat_release(struct inode *inode, struct file *file)
{
	unsigned int minor = iminor(inode);
	struct roccat_reader *reader = file->private_data;
	struct roccat_device *device;

	mutex_lock(&devices_lock);

	device = devices[minor];
	if (!device) {
		mutex_unlock(&devices_lock);
		pr_emerg("roccat device with minor %d doesn't exist\n", minor);
		return -ENODEV;
	}

	mutex_lock(&device->readers_lock);
	list_del(&reader->node);
	mutex_unlock(&device->readers_lock);
	kfree(reader);

	if (!--device->open) {
		/* removing last reader */
		if (device->exist) {
			hid_hw_power(device->hid, PM_HINT_NORMAL);
			hid_hw_close(device->hid);
		} else {
			kfree(device);
		}
	}

	mutex_unlock(&devices_lock);

	return 0;
}

/*
 * roccat_report_event() - output data to readers
 * @minor: minor device number returned by roccat_connect()
 * @data: pointer to data
 * @len: size of data
 *
 * Return value is zero on success, a negative error code on failure.
 *
 * This is called from interrupt handler.
 */
int roccat_report_event(int minor, u8 const *data, int len)
{
	struct roccat_device *device;
	struct roccat_reader *reader;
	struct roccat_report *report;
	uint8_t *new_value;

	new_value = kmemdup(data, len, GFP_ATOMIC);
	if (!new_value)
		return -ENOMEM;

	device = devices[minor];

	report = &device->cbuf[device->cbuf_end];

	/* passing NULL is safe */
	kfree(report->value);

	report->value = new_value;
	report->len = len;
	device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;

	list_for_each_entry(reader, &device->readers, node) {
		/*
		 * As we already inserted one element, the buffer can't be
		 * empty. If start and end are equal, buffer is full and we
		 * increase start, so that slow reader misses one event, but
		 * gets the newer ones in the right order.
		 */
		if (reader->cbuf_start == device->cbuf_end)
			reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
	}

	wake_up_interruptible(&device->wait);
	return 0;
}
EXPORT_SYMBOL_GPL(roccat_report_event);

/*
 * roccat_connect() - create a char device for special event output
 * @hid: the hid device the char device should be connected to.
 *
 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
 * success, a negative error code on failure.
 */
int roccat_connect(struct hid_device *hid)
{
	unsigned int minor;
	struct roccat_device *device;
	int temp;

	device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
	if (!device)
		return -ENOMEM;

	mutex_lock(&devices_lock);

	for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
		if (devices[minor])
			continue;
		break;
	}

	if (minor < ROCCAT_MAX_DEVICES) {
		devices[minor] = device;
	} else {
		mutex_unlock(&devices_lock);
		kfree(device);
		return -EINVAL;
	}

	device->dev = device_create(roccat_class, &hid->dev,
			MKDEV(roccat_major, minor), NULL,
			"%s%s%d", "roccat", hid->driver->name, minor);

	if (IS_ERR(device->dev)) {
		devices[minor] = NULL;
		mutex_unlock(&devices_lock);
		temp = PTR_ERR(device->dev);
		kfree(device);
		return temp;
	}

	mutex_unlock(&devices_lock);

	init_waitqueue_head(&device->wait);
	INIT_LIST_HEAD(&device->readers);
	mutex_init(&device->readers_lock);
	mutex_init(&device->cbuf_lock);
	device->minor = minor;
	device->hid = hid;
	device->exist = 1;
	device->cbuf_end = 0;

	return minor;
}
EXPORT_SYMBOL_GPL(roccat_connect);

/* roccat_disconnect() - remove char device from hid device
 * @minor: the minor device number returned by roccat_connect()
 */
void roccat_disconnect(int minor)
{
	struct roccat_device *device;

	mutex_lock(&devices_lock);
	device = devices[minor];
	devices[minor] = NULL;
	mutex_unlock(&devices_lock);

	device->exist = 0; /* TODO exist maybe not needed */

	device_destroy(roccat_class, MKDEV(roccat_major, minor));

	if (device->open) {
		hid_hw_close(device->hid);
		wake_up_interruptible(&device->wait);
	} else {
		kfree(device);
	}
}
EXPORT_SYMBOL_GPL(roccat_disconnect);

static const struct file_operations roccat_ops = {
	.owner = THIS_MODULE,
	.read = roccat_read,
	.poll = roccat_poll,
	.open = roccat_open,
	.release = roccat_release,
	.llseek = noop_llseek,
};

static int __init roccat_init(void)
{
	int retval;
	dev_t dev_id;

	retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
			ROCCAT_MAX_DEVICES, "roccat");

	roccat_major = MAJOR(dev_id);

	if (retval < 0) {
		pr_warn("can't get major number\n");
		return retval;
	}

	roccat_class = class_create(THIS_MODULE, "roccat");
	if (IS_ERR(roccat_class)) {
		retval = PTR_ERR(roccat_class);
		unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
		return retval;
	}

	cdev_init(&roccat_cdev, &roccat_ops);
	cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);

	return 0;
}

static void __exit roccat_exit(void)
{
	dev_t dev_id = MKDEV(roccat_major, 0);

	cdev_del(&roccat_cdev);
	class_destroy(roccat_class);
	unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
}

module_init(roccat_init);
module_exit(roccat_exit);

MODULE_AUTHOR("Stefan Achatz");
MODULE_DESCRIPTION("USB Roccat char device");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
206f5f2f SA	1	/*
	2	* Roccat driver for Linux
	3	*
	4	* Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net>
	5	*/
	6
	7	/*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License as published by the Free
	10	* Software Foundation; either version 2 of the License, or (at your option)
	11	* any later version.
	12	*/
	13
	14	/*
	15	* Module roccat is a char device used to report special events of roccat
	16	* hardware to userland. These events include requests for on-screen-display of
	17	* profile or dpi settings or requests for execution of macro sequences that are
	18	* not stored in device. The information in these events depends on hid device
	19	* implementation and contains data that is not available in a single hid event
	20	* or else hidraw could have been used.
	21	* It is inspired by hidraw, but uses only one circular buffer for all readers.
	22	*/
	23
4291ee30 JP	24	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
4291ee30 JP	25
206f5f2f SA	26	#include <linux/cdev.h>
	27	#include <linux/poll.h>
	28	#include <linux/sched.h>
	29
	30	#include "hid-roccat.h"
	31
	32	#define ROCCAT_FIRST_MINOR 0
	33	#define ROCCAT_MAX_DEVICES 8
	34
	35	/* should be a power of 2 for performance reason */
	36	#define ROCCAT_CBUF_SIZE 16
	37
	38	struct roccat_report {
	39	uint8_t *value;
	40	int len;
	41	};
	42
	43	struct roccat_device {
	44	unsigned int minor;
	45	int open;
	46	int exist;
	47	wait_queue_head_t wait;
	48	struct device *dev;
	49	struct hid_device *hid;
	50	struct list_head readers;
	51	/* protects modifications of readers list */
	52	struct mutex readers_lock;
	53
	54	/*
	55	* circular_buffer has one writer and multiple readers with their own
	56	* read pointers
	57	*/
	58	struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
	59	int cbuf_end;
	60	struct mutex cbuf_lock;
	61	};
	62
	63	struct roccat_reader {
	64	struct list_head node;
	65	struct roccat_device *device;
	66	int cbuf_start;
	67	};
	68
	69	static int roccat_major;
	70	static struct class *roccat_class;
	71	static struct cdev roccat_cdev;
	72
	73	static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
	74	/* protects modifications of devices array */
	75	static DEFINE_MUTEX(devices_lock);
	76
	77	static ssize_t roccat_read(struct file file, char __user buffer,
	78	size_t count, loff_t *ppos)
	79	{
	80	struct roccat_reader *reader = file->private_data;
	81	struct roccat_device *device = reader->device;
	82	struct roccat_report *report;
	83	ssize_t retval = 0, len;
	84	DECLARE_WAITQUEUE(wait, current);
	85
	86	mutex_lock(&device->cbuf_lock);
	87
	88	/* no data? */
	89	if (reader->cbuf_start == device->cbuf_end) {
90	add_wait_queue(&device->wait, &wait);
91	set_current_state(TASK_INTERRUPTIBLE);
92
93	/* wait for data */
94	while (reader->cbuf_start == device->cbuf_end) {
95	if (file->f_flags & O_NONBLOCK) {
96	retval = -EAGAIN;
97	break;
98	}
99	if (signal_pending(current)) {
100	retval = -ERESTARTSYS;
101	break;
102	}
103	if (!device->exist) {
104	retval = -EIO;
105	break;
106	}
107
108	mutex_unlock(&device->cbuf_lock);
109	schedule();
110	mutex_lock(&device->cbuf_lock);
111	set_current_state(TASK_INTERRUPTIBLE);
112	}
113
114	set_current_state(TASK_RUNNING);
115	remove_wait_queue(&device->wait, &wait);
116	}
117
118	/* here we either have data or a reason to return if retval is set */
119	if (retval)
120	goto exit_unlock;
121
122	report = &device->cbuf[reader->cbuf_start];
123	/*
124	* If report is larger than requested amount of data, rest of report
125	* is lost!
126	*/
127	len = report->len > count ? count : report->len;
128
129	if (copy_to_user(buffer, report->value, len)) {
130	retval = -EFAULT;
131	goto exit_unlock;
132	}
133	retval += len;
134	reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
135
136	exit_unlock:
137	mutex_unlock(&device->cbuf_lock);
138	return retval;
139	}
140
141	static unsigned int roccat_poll(struct file file, poll_table wait)
142	{
143	struct roccat_reader *reader = file->private_data;
144	poll_wait(file, &reader->device->wait, wait);
145	if (reader->cbuf_start != reader->device->cbuf_end)
146	return POLLIN \| POLLRDNORM;
147	if (!reader->device->exist)
148	return POLLERR \| POLLHUP;
149	return 0;
150	}
151
152	static int roccat_open(struct inode inode, struct file file)
153	{
154	unsigned int minor = iminor(inode);
155	struct roccat_reader *reader;
156	struct roccat_device *device;
157	int error = 0;
158
159	reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
160	if (!reader)
161	return -ENOMEM;
162
163	mutex_lock(&devices_lock);
164
165	device = devices[minor];
166
167	mutex_lock(&device->readers_lock);
168
169	if (!device) {
4291ee30	170	pr_emerg("roccat device with minor %d doesn't exist\n", minor);
206f5f2f	171	error = -ENODEV;
dfe5c7b7	172	goto exit_err;
206f5f2f SA	173	}
	174
	175	if (!device->open++) {
	176	/* power on device on adding first reader */
5bea7660 DT	177	error = hid_hw_power(device->hid, PM_HINT_FULLON);
	178	if (error < 0) {
	179	--device->open;
	180	goto exit_err;
206f5f2f	181	}
5bea7660 DT	182
5bea7660 DT	183	error = hid_hw_open(device->hid);
206f5f2f	184	if (error < 0) {
5bea7660	185	hid_hw_power(device->hid, PM_HINT_NORMAL);
206f5f2f	186	--device->open;
dfe5c7b7	187	goto exit_err;
206f5f2f SA	188	}
	189	}
	190
	191	reader->device = device;
	192	/* new reader doesn't get old events */
	193	reader->cbuf_start = device->cbuf_end;
	194
	195	list_add_tail(&reader->node, &device->readers);
	196	file->private_data = reader;
	197
	198	exit_unlock:
	199	mutex_unlock(&device->readers_lock);
	200	mutex_unlock(&devices_lock);
	201	return error;
dfe5c7b7 JL	202	exit_err:
	203	kfree(reader);
	204	goto exit_unlock;
206f5f2f SA	205	}
	206
	207	static int roccat_release(struct inode inode, struct file file)
	208	{
	209	unsigned int minor = iminor(inode);
	210	struct roccat_reader *reader = file->private_data;
	211	struct roccat_device *device;
	212
	213	mutex_lock(&devices_lock);
	214
	215	device = devices[minor];
	216	if (!device) {
	217	mutex_unlock(&devices_lock);
4291ee30	218	pr_emerg("roccat device with minor %d doesn't exist\n", minor);
206f5f2f SA	219	return -ENODEV;
	220	}
	221
	222	mutex_lock(&device->readers_lock);
	223	list_del(&reader->node);
	224	mutex_unlock(&device->readers_lock);
	225	kfree(reader);
	226
	227	if (!--device->open) {
	228	/* removing last reader */
	229	if (device->exist) {
5bea7660 DT	230	hid_hw_power(device->hid, PM_HINT_NORMAL);
5bea7660 DT	231	hid_hw_close(device->hid);
206f5f2f SA	232	} else {
	233	kfree(device);
	234	}
	235	}
	236
	237	mutex_unlock(&devices_lock);
	238
	239	return 0;
	240	}
	241
	242	/*
	243	* roccat_report_event() - output data to readers
	244	* @minor: minor device number returned by roccat_connect()
	245	* @data: pointer to data
	246	* @len: size of data
	247	*
	248	* Return value is zero on success, a negative error code on failure.
	249	*
	250	* This is called from interrupt handler.
	251	*/
	252	int roccat_report_event(int minor, u8 const *data, int len)
	253	{
	254	struct roccat_device *device;
	255	struct roccat_reader *reader;
	256	struct roccat_report *report;
	257	uint8_t *new_value;
	258
	259	new_value = kmemdup(data, len, GFP_ATOMIC);
	260	if (!new_value)
	261	return -ENOMEM;
	262
	263	device = devices[minor];
	264
	265	report = &device->cbuf[device->cbuf_end];
	266
	267	/* passing NULL is safe */
	268	kfree(report->value);
	269
	270	report->value = new_value;
	271	report->len = len;
	272	device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;
	273
	274	list_for_each_entry(reader, &device->readers, node) {
	275	/*
	276	* As we already inserted one element, the buffer can't be
	277	* empty. If start and end are equal, buffer is full and we
	278	* increase start, so that slow reader misses one event, but
	279	* gets the newer ones in the right order.
	280	*/
	281	if (reader->cbuf_start == device->cbuf_end)
	282	reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
	283	}
	284
	285	wake_up_interruptible(&device->wait);
	286	return 0;
	287	}
	288	EXPORT_SYMBOL_GPL(roccat_report_event);
	289
	290	/*
	291	* roccat_connect() - create a char device for special event output
	292	* @hid: the hid device the char device should be connected to.
	293	*
	294	* Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
	295	* success, a negative error code on failure.
296	*/
297	int roccat_connect(struct hid_device *hid)
298	{
299	unsigned int minor;
300	struct roccat_device *device;
301	int temp;
302
303	device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
304	if (!device)
305	return -ENOMEM;
306
307	mutex_lock(&devices_lock);
308
309	for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
310	if (devices[minor])
311	continue;
312	break;
313	}
314
315	if (minor < ROCCAT_MAX_DEVICES) {
316	devices[minor] = device;
317	} else {
318	mutex_unlock(&devices_lock);
319	kfree(device);
320	return -EINVAL;
321	}
322
323	device->dev = device_create(roccat_class, &hid->dev,
324	MKDEV(roccat_major, minor), NULL,
325	"%s%s%d", "roccat", hid->driver->name, minor);
326
327	if (IS_ERR(device->dev)) {
328	devices[minor] = NULL;
329	mutex_unlock(&devices_lock);
330	temp = PTR_ERR(device->dev);
331	kfree(device);
332	return temp;
333	}
334
335	mutex_unlock(&devices_lock);
336
337	init_waitqueue_head(&device->wait);
338	INIT_LIST_HEAD(&device->readers);
339	mutex_init(&device->readers_lock);
340	mutex_init(&device->cbuf_lock);
341	device->minor = minor;
342	device->hid = hid;
343	device->exist = 1;
344	device->cbuf_end = 0;
345
346	return minor;
347	}
348	EXPORT_SYMBOL_GPL(roccat_connect);
349
350	/* roccat_disconnect() - remove char device from hid device
351	* @minor: the minor device number returned by roccat_connect()
352	*/
353	void roccat_disconnect(int minor)
354	{
355	struct roccat_device *device;
356
357	mutex_lock(&devices_lock);
358	device = devices[minor];
359	devices[minor] = NULL;
360	mutex_unlock(&devices_lock);
361
362	device->exist = 0; /* TODO exist maybe not needed */
363
364	device_destroy(roccat_class, MKDEV(roccat_major, minor));
365
366	if (device->open) {
5bea7660	367	hid_hw_close(device->hid);
206f5f2f SA	368	wake_up_interruptible(&device->wait);
	369	} else {
	370	kfree(device);
	371	}
	372	}
	373	EXPORT_SYMBOL_GPL(roccat_disconnect);
	374
	375	static const struct file_operations roccat_ops = {
	376	.owner = THIS_MODULE,
	377	.read = roccat_read,
	378	.poll = roccat_poll,
	379	.open = roccat_open,
	380	.release = roccat_release,
6038f373	381	.llseek = noop_llseek,
206f5f2f SA	382	};
	383
	384	static int __init roccat_init(void)
	385	{
	386	int retval;
	387	dev_t dev_id;
	388
	389	retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
	390	ROCCAT_MAX_DEVICES, "roccat");
	391
	392	roccat_major = MAJOR(dev_id);
	393
	394	if (retval < 0) {
4291ee30	395	pr_warn("can't get major number\n");
206f5f2f SA	396	return retval;
	397	}
	398
	399	roccat_class = class_create(THIS_MODULE, "roccat");
	400	if (IS_ERR(roccat_class)) {
	401	retval = PTR_ERR(roccat_class);
	402	unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
	403	return retval;
	404	}
	405
	406	cdev_init(&roccat_cdev, &roccat_ops);
	407	cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);
	408
	409	return 0;
	410	}
	411
	412	static void __exit roccat_exit(void)
	413	{
	414	dev_t dev_id = MKDEV(roccat_major, 0);
	415
	416	cdev_del(&roccat_cdev);
	417	class_destroy(roccat_class);
	418	unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
	419	}
	420
	421	module_init(roccat_init);
	422	module_exit(roccat_exit);
	423
	424	MODULE_AUTHOR("Stefan Achatz");
	425	MODULE_DESCRIPTION("USB Roccat char device");
	426	MODULE_LICENSE("GPL v2");