Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
[sfrench/cifs-2.6.git] / drivers / hid / hid-roccat.c
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
24 #include <linux/cdev.h>
25 #include <linux/poll.h>
26 #include <linux/sched.h>
27
28 #include "hid-roccat.h"
29
30 #define ROCCAT_FIRST_MINOR 0
31 #define ROCCAT_MAX_DEVICES 8
32
33 /* should be a power of 2 for performance reason */
34 #define ROCCAT_CBUF_SIZE 16
35
36 struct roccat_report {
37         uint8_t *value;
38         int len;
39 };
40
41 struct roccat_device {
42         unsigned int minor;
43         int open;
44         int exist;
45         wait_queue_head_t wait;
46         struct device *dev;
47         struct hid_device *hid;
48         struct list_head readers;
49         /* protects modifications of readers list */
50         struct mutex readers_lock;
51
52         /*
53          * circular_buffer has one writer and multiple readers with their own
54          * read pointers
55          */
56         struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
57         int cbuf_end;
58         struct mutex cbuf_lock;
59 };
60
61 struct roccat_reader {
62         struct list_head node;
63         struct roccat_device *device;
64         int cbuf_start;
65 };
66
67 static int roccat_major;
68 static struct class *roccat_class;
69 static struct cdev roccat_cdev;
70
71 static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
72 /* protects modifications of devices array */
73 static DEFINE_MUTEX(devices_lock);
74
75 static ssize_t roccat_read(struct file *file, char __user *buffer,
76                 size_t count, loff_t *ppos)
77 {
78         struct roccat_reader *reader = file->private_data;
79         struct roccat_device *device = reader->device;
80         struct roccat_report *report;
81         ssize_t retval = 0, len;
82         DECLARE_WAITQUEUE(wait, current);
83
84         mutex_lock(&device->cbuf_lock);
85
86         /* no data? */
87         if (reader->cbuf_start == device->cbuf_end) {
88                 add_wait_queue(&device->wait, &wait);
89                 set_current_state(TASK_INTERRUPTIBLE);
90
91                 /* wait for data */
92                 while (reader->cbuf_start == device->cbuf_end) {
93                         if (file->f_flags & O_NONBLOCK) {
94                                 retval = -EAGAIN;
95                                 break;
96                         }
97                         if (signal_pending(current)) {
98                                 retval = -ERESTARTSYS;
99                                 break;
100                         }
101                         if (!device->exist) {
102                                 retval = -EIO;
103                                 break;
104                         }
105
106                         mutex_unlock(&device->cbuf_lock);
107                         schedule();
108                         mutex_lock(&device->cbuf_lock);
109                         set_current_state(TASK_INTERRUPTIBLE);
110                 }
111
112                 set_current_state(TASK_RUNNING);
113                 remove_wait_queue(&device->wait, &wait);
114         }
115
116         /* here we either have data or a reason to return if retval is set */
117         if (retval)
118                 goto exit_unlock;
119
120         report = &device->cbuf[reader->cbuf_start];
121         /*
122          * If report is larger than requested amount of data, rest of report
123          * is lost!
124          */
125         len = report->len > count ? count : report->len;
126
127         if (copy_to_user(buffer, report->value, len)) {
128                 retval = -EFAULT;
129                 goto exit_unlock;
130         }
131         retval += len;
132         reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
133
134 exit_unlock:
135         mutex_unlock(&device->cbuf_lock);
136         return retval;
137 }
138
139 static unsigned int roccat_poll(struct file *file, poll_table *wait)
140 {
141         struct roccat_reader *reader = file->private_data;
142         poll_wait(file, &reader->device->wait, wait);
143         if (reader->cbuf_start != reader->device->cbuf_end)
144                 return POLLIN | POLLRDNORM;
145         if (!reader->device->exist)
146                 return POLLERR | POLLHUP;
147         return 0;
148 }
149
150 static int roccat_open(struct inode *inode, struct file *file)
151 {
152         unsigned int minor = iminor(inode);
153         struct roccat_reader *reader;
154         struct roccat_device *device;
155         int error = 0;
156
157         reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
158         if (!reader)
159                 return -ENOMEM;
160
161         mutex_lock(&devices_lock);
162
163         device = devices[minor];
164
165         mutex_lock(&device->readers_lock);
166
167         if (!device) {
168                 printk(KERN_EMERG "roccat device with minor %d doesn't exist\n",
169                                 minor);
170                 error = -ENODEV;
171                 goto exit_unlock;
172         }
173
174         if (!device->open++) {
175                 /* power on device on adding first reader */
176                 if (device->hid->ll_driver->power) {
177                         error = device->hid->ll_driver->power(device->hid,
178                                         PM_HINT_FULLON);
179                         if (error < 0) {
180                                 --device->open;
181                                 goto exit_unlock;
182                         }
183                 }
184                 error = device->hid->ll_driver->open(device->hid);
185                 if (error < 0) {
186                         if (device->hid->ll_driver->power)
187                                 device->hid->ll_driver->power(device->hid,
188                                                 PM_HINT_NORMAL);
189                         --device->open;
190                         goto exit_unlock;
191                 }
192         }
193
194         reader->device = device;
195         /* new reader doesn't get old events */
196         reader->cbuf_start = device->cbuf_end;
197
198         list_add_tail(&reader->node, &device->readers);
199         file->private_data = reader;
200
201 exit_unlock:
202         mutex_unlock(&device->readers_lock);
203         mutex_unlock(&devices_lock);
204         return error;
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);
218                 printk(KERN_EMERG "roccat device with minor %d doesn't exist\n",
219                                 minor);
220                 return -ENODEV;
221         }
222
223         mutex_lock(&device->readers_lock);
224         list_del(&reader->node);
225         mutex_unlock(&device->readers_lock);
226         kfree(reader);
227
228         if (!--device->open) {
229                 /* removing last reader */
230                 if (device->exist) {
231                         if (device->hid->ll_driver->power)
232                                 device->hid->ll_driver->power(device->hid,
233                                                 PM_HINT_NORMAL);
234                         device->hid->ll_driver->close(device->hid);
235                 } else {
236                         kfree(device);
237                 }
238         }
239
240         mutex_unlock(&devices_lock);
241
242         return 0;
243 }
244
245 /*
246  * roccat_report_event() - output data to readers
247  * @minor: minor device number returned by roccat_connect()
248  * @data: pointer to data
249  * @len: size of data
250  *
251  * Return value is zero on success, a negative error code on failure.
252  *
253  * This is called from interrupt handler.
254  */
255 int roccat_report_event(int minor, u8 const *data, int len)
256 {
257         struct roccat_device *device;
258         struct roccat_reader *reader;
259         struct roccat_report *report;
260         uint8_t *new_value;
261
262         new_value = kmemdup(data, len, GFP_ATOMIC);
263         if (!new_value)
264                 return -ENOMEM;
265
266         device = devices[minor];
267
268         report = &device->cbuf[device->cbuf_end];
269
270         /* passing NULL is safe */
271         kfree(report->value);
272
273         report->value = new_value;
274         report->len = len;
275         device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;
276
277         list_for_each_entry(reader, &device->readers, node) {
278                 /*
279                  * As we already inserted one element, the buffer can't be
280                  * empty. If start and end are equal, buffer is full and we
281                  * increase start, so that slow reader misses one event, but
282                  * gets the newer ones in the right order.
283                  */
284                 if (reader->cbuf_start == device->cbuf_end)
285                         reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
286         }
287
288         wake_up_interruptible(&device->wait);
289         return 0;
290 }
291 EXPORT_SYMBOL_GPL(roccat_report_event);
292
293 /*
294  * roccat_connect() - create a char device for special event output
295  * @hid: the hid device the char device should be connected to.
296  *
297  * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
298  * success, a negative error code on failure.
299  */
300 int roccat_connect(struct hid_device *hid)
301 {
302         unsigned int minor;
303         struct roccat_device *device;
304         int temp;
305
306         device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
307         if (!device)
308                 return -ENOMEM;
309
310         mutex_lock(&devices_lock);
311
312         for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
313                 if (devices[minor])
314                         continue;
315                 break;
316         }
317
318         if (minor < ROCCAT_MAX_DEVICES) {
319                 devices[minor] = device;
320         } else {
321                 mutex_unlock(&devices_lock);
322                 kfree(device);
323                 return -EINVAL;
324         }
325
326         device->dev = device_create(roccat_class, &hid->dev,
327                         MKDEV(roccat_major, minor), NULL,
328                         "%s%s%d", "roccat", hid->driver->name, minor);
329
330         if (IS_ERR(device->dev)) {
331                 devices[minor] = NULL;
332                 mutex_unlock(&devices_lock);
333                 temp = PTR_ERR(device->dev);
334                 kfree(device);
335                 return temp;
336         }
337
338         mutex_unlock(&devices_lock);
339
340         init_waitqueue_head(&device->wait);
341         INIT_LIST_HEAD(&device->readers);
342         mutex_init(&device->readers_lock);
343         mutex_init(&device->cbuf_lock);
344         device->minor = minor;
345         device->hid = hid;
346         device->exist = 1;
347         device->cbuf_end = 0;
348
349         return minor;
350 }
351 EXPORT_SYMBOL_GPL(roccat_connect);
352
353 /* roccat_disconnect() - remove char device from hid device
354  * @minor: the minor device number returned by roccat_connect()
355  */
356 void roccat_disconnect(int minor)
357 {
358         struct roccat_device *device;
359
360         mutex_lock(&devices_lock);
361         device = devices[minor];
362         devices[minor] = NULL;
363         mutex_unlock(&devices_lock);
364
365         device->exist = 0; /* TODO exist maybe not needed */
366
367         device_destroy(roccat_class, MKDEV(roccat_major, minor));
368
369         if (device->open) {
370                 device->hid->ll_driver->close(device->hid);
371                 wake_up_interruptible(&device->wait);
372         } else {
373                 kfree(device);
374         }
375 }
376 EXPORT_SYMBOL_GPL(roccat_disconnect);
377
378 static const struct file_operations roccat_ops = {
379         .owner = THIS_MODULE,
380         .read = roccat_read,
381         .poll = roccat_poll,
382         .open = roccat_open,
383         .release = roccat_release,
384 };
385
386 static int __init roccat_init(void)
387 {
388         int retval;
389         dev_t dev_id;
390
391         retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
392                         ROCCAT_MAX_DEVICES, "roccat");
393
394         roccat_major = MAJOR(dev_id);
395
396         if (retval < 0) {
397                 printk(KERN_WARNING "roccat: can't get major number\n");
398                 return retval;
399         }
400
401         roccat_class = class_create(THIS_MODULE, "roccat");
402         if (IS_ERR(roccat_class)) {
403                 retval = PTR_ERR(roccat_class);
404                 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
405                 return retval;
406         }
407
408         cdev_init(&roccat_cdev, &roccat_ops);
409         cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);
410
411         return 0;
412 }
413
414 static void __exit roccat_exit(void)
415 {
416         dev_t dev_id = MKDEV(roccat_major, 0);
417
418         cdev_del(&roccat_cdev);
419         class_destroy(roccat_class);
420         unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
421 }
422
423 module_init(roccat_init);
424 module_exit(roccat_exit);
425
426 MODULE_AUTHOR("Stefan Achatz");
427 MODULE_DESCRIPTION("USB Roccat char device");
428 MODULE_LICENSE("GPL v2");