Tools: hv: kvp: eliminate 'may be used uninitialized' warning
[linux/fpc-iii.git] / drivers / input / ff-core.c
blob8f2042432c85151b25fab1e885fe321e1563d641
1 /*
2 * Force feedback support for Linux input subsystem
4 * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
5 * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
6 */
8 /*
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 /* #define DEBUG */
26 #include <linux/input.h>
27 #include <linux/module.h>
28 #include <linux/mutex.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
33 * Check that the effect_id is a valid effect and whether the user
34 * is the owner
36 static int check_effect_access(struct ff_device *ff, int effect_id,
37 struct file *file)
39 if (effect_id < 0 || effect_id >= ff->max_effects ||
40 !ff->effect_owners[effect_id])
41 return -EINVAL;
43 if (file && ff->effect_owners[effect_id] != file)
44 return -EACCES;
46 return 0;
50 * Checks whether 2 effects can be combined together
52 static inline int check_effects_compatible(struct ff_effect *e1,
53 struct ff_effect *e2)
55 return e1->type == e2->type &&
56 (e1->type != FF_PERIODIC ||
57 e1->u.periodic.waveform == e2->u.periodic.waveform);
61 * Convert an effect into compatible one
63 static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
65 int magnitude;
67 switch (effect->type) {
68 case FF_RUMBLE:
69 if (!test_bit(FF_PERIODIC, ff->ffbit))
70 return -EINVAL;
73 * calculate magnitude of sine wave as average of rumble's
74 * 2/3 of strong magnitude and 1/3 of weak magnitude
76 magnitude = effect->u.rumble.strong_magnitude / 3 +
77 effect->u.rumble.weak_magnitude / 6;
79 effect->type = FF_PERIODIC;
80 effect->u.periodic.waveform = FF_SINE;
81 effect->u.periodic.period = 50;
82 effect->u.periodic.magnitude = max(magnitude, 0x7fff);
83 effect->u.periodic.offset = 0;
84 effect->u.periodic.phase = 0;
85 effect->u.periodic.envelope.attack_length = 0;
86 effect->u.periodic.envelope.attack_level = 0;
87 effect->u.periodic.envelope.fade_length = 0;
88 effect->u.periodic.envelope.fade_level = 0;
90 return 0;
92 default:
93 /* Let driver handle conversion */
94 return 0;
98 /**
99 * input_ff_upload() - upload effect into force-feedback device
100 * @dev: input device
101 * @effect: effect to be uploaded
102 * @file: owner of the effect
104 int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
105 struct file *file)
107 struct ff_device *ff = dev->ff;
108 struct ff_effect *old;
109 int ret = 0;
110 int id;
112 if (!test_bit(EV_FF, dev->evbit))
113 return -ENOSYS;
115 if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
116 !test_bit(effect->type, dev->ffbit)) {
117 dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
118 return -EINVAL;
121 if (effect->type == FF_PERIODIC &&
122 (effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
123 effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
124 !test_bit(effect->u.periodic.waveform, dev->ffbit))) {
125 dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
126 return -EINVAL;
129 if (!test_bit(effect->type, ff->ffbit)) {
130 ret = compat_effect(ff, effect);
131 if (ret)
132 return ret;
135 mutex_lock(&ff->mutex);
137 if (effect->id == -1) {
138 for (id = 0; id < ff->max_effects; id++)
139 if (!ff->effect_owners[id])
140 break;
142 if (id >= ff->max_effects) {
143 ret = -ENOSPC;
144 goto out;
147 effect->id = id;
148 old = NULL;
150 } else {
151 id = effect->id;
153 ret = check_effect_access(ff, id, file);
154 if (ret)
155 goto out;
157 old = &ff->effects[id];
159 if (!check_effects_compatible(effect, old)) {
160 ret = -EINVAL;
161 goto out;
165 ret = ff->upload(dev, effect, old);
166 if (ret)
167 goto out;
169 spin_lock_irq(&dev->event_lock);
170 ff->effects[id] = *effect;
171 ff->effect_owners[id] = file;
172 spin_unlock_irq(&dev->event_lock);
174 out:
175 mutex_unlock(&ff->mutex);
176 return ret;
178 EXPORT_SYMBOL_GPL(input_ff_upload);
181 * Erases the effect if the requester is also the effect owner. The mutex
182 * should already be locked before calling this function.
184 static int erase_effect(struct input_dev *dev, int effect_id,
185 struct file *file)
187 struct ff_device *ff = dev->ff;
188 int error;
190 error = check_effect_access(ff, effect_id, file);
191 if (error)
192 return error;
194 spin_lock_irq(&dev->event_lock);
195 ff->playback(dev, effect_id, 0);
196 ff->effect_owners[effect_id] = NULL;
197 spin_unlock_irq(&dev->event_lock);
199 if (ff->erase) {
200 error = ff->erase(dev, effect_id);
201 if (error) {
202 spin_lock_irq(&dev->event_lock);
203 ff->effect_owners[effect_id] = file;
204 spin_unlock_irq(&dev->event_lock);
206 return error;
210 return 0;
214 * input_ff_erase - erase a force-feedback effect from device
215 * @dev: input device to erase effect from
216 * @effect_id: id of the effect to be erased
217 * @file: purported owner of the request
219 * This function erases a force-feedback effect from specified device.
220 * The effect will only be erased if it was uploaded through the same
221 * file handle that is requesting erase.
223 int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
225 struct ff_device *ff = dev->ff;
226 int ret;
228 if (!test_bit(EV_FF, dev->evbit))
229 return -ENOSYS;
231 mutex_lock(&ff->mutex);
232 ret = erase_effect(dev, effect_id, file);
233 mutex_unlock(&ff->mutex);
235 return ret;
237 EXPORT_SYMBOL_GPL(input_ff_erase);
240 * flush_effects - erase all effects owned by a file handle
242 static int flush_effects(struct input_dev *dev, struct file *file)
244 struct ff_device *ff = dev->ff;
245 int i;
247 dev_dbg(&dev->dev, "flushing now\n");
249 mutex_lock(&ff->mutex);
251 for (i = 0; i < ff->max_effects; i++)
252 erase_effect(dev, i, file);
254 mutex_unlock(&ff->mutex);
256 return 0;
260 * input_ff_event() - generic handler for force-feedback events
261 * @dev: input device to send the effect to
262 * @type: event type (anything but EV_FF is ignored)
263 * @code: event code
264 * @value: event value
266 int input_ff_event(struct input_dev *dev, unsigned int type,
267 unsigned int code, int value)
269 struct ff_device *ff = dev->ff;
271 if (type != EV_FF)
272 return 0;
274 switch (code) {
275 case FF_GAIN:
276 if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
277 break;
279 ff->set_gain(dev, value);
280 break;
282 case FF_AUTOCENTER:
283 if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
284 break;
286 ff->set_autocenter(dev, value);
287 break;
289 default:
290 if (check_effect_access(ff, code, NULL) == 0)
291 ff->playback(dev, code, value);
292 break;
295 return 0;
297 EXPORT_SYMBOL_GPL(input_ff_event);
300 * input_ff_create() - create force-feedback device
301 * @dev: input device supporting force-feedback
302 * @max_effects: maximum number of effects supported by the device
304 * This function allocates all necessary memory for a force feedback
305 * portion of an input device and installs all default handlers.
306 * @dev->ffbit should be already set up before calling this function.
307 * Once ff device is created you need to setup its upload, erase,
308 * playback and other handlers before registering input device
310 int input_ff_create(struct input_dev *dev, unsigned int max_effects)
312 struct ff_device *ff;
313 size_t ff_dev_size;
314 int i;
316 if (!max_effects) {
317 dev_err(&dev->dev, "cannot allocate device without any effects\n");
318 return -EINVAL;
321 if (max_effects > FF_MAX_EFFECTS) {
322 dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
323 return -EINVAL;
326 ff_dev_size = sizeof(struct ff_device) +
327 max_effects * sizeof(struct file *);
328 if (ff_dev_size < max_effects) /* overflow */
329 return -EINVAL;
331 ff = kzalloc(ff_dev_size, GFP_KERNEL);
332 if (!ff)
333 return -ENOMEM;
335 ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
336 GFP_KERNEL);
337 if (!ff->effects) {
338 kfree(ff);
339 return -ENOMEM;
342 ff->max_effects = max_effects;
343 mutex_init(&ff->mutex);
345 dev->ff = ff;
346 dev->flush = flush_effects;
347 dev->event = input_ff_event;
348 __set_bit(EV_FF, dev->evbit);
350 /* Copy "true" bits into ff device bitmap */
351 for_each_set_bit(i, dev->ffbit, FF_CNT)
352 __set_bit(i, ff->ffbit);
354 /* we can emulate RUMBLE with periodic effects */
355 if (test_bit(FF_PERIODIC, ff->ffbit))
356 __set_bit(FF_RUMBLE, dev->ffbit);
358 return 0;
360 EXPORT_SYMBOL_GPL(input_ff_create);
363 * input_ff_destroy() - frees force feedback portion of input device
364 * @dev: input device supporting force feedback
366 * This function is only needed in error path as input core will
367 * automatically free force feedback structures when device is
368 * destroyed.
370 void input_ff_destroy(struct input_dev *dev)
372 struct ff_device *ff = dev->ff;
374 __clear_bit(EV_FF, dev->evbit);
375 if (ff) {
376 if (ff->destroy)
377 ff->destroy(ff);
378 kfree(ff->private);
379 kfree(ff->effects);
380 kfree(ff);
381 dev->ff = NULL;
384 EXPORT_SYMBOL_GPL(input_ff_destroy);