/* * Force feedback support for Linux input subsystem * * Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com> * Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru> */ /* * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* #define DEBUG */ #define debug(format, arg...) pr_debug("ff-core: " format "\n", ## arg) #include <linux/input.h> #include <linux/module.h> #include <linux/mutex.h> /* * Check that the effect_id is a valid effect and whether the user * is the owner */ static int check_effect_access(struct ff_device *ff, int effect_id, struct file *file) { if (effect_id < 0 || effect_id >= ff->max_effects || !ff->effect_owners[effect_id]) return -EINVAL; if (file && ff->effect_owners[effect_id] != file) return -EACCES; return 0; } /* * Checks whether 2 effects can be combined together */ static inline int check_effects_compatible(struct ff_effect *e1, struct ff_effect *e2) { return e1->type == e2->type && (e1->type != FF_PERIODIC || e1->u.periodic.waveform == e2->u.periodic.waveform); } /* * Convert an effect into compatible one */ static int compat_effect(struct ff_device *ff, struct ff_effect *effect) { int magnitude; switch (effect->type) { case FF_RUMBLE: if (!test_bit(FF_PERIODIC, ff->ffbit)) return -EINVAL; /* * calculate manginude of sine wave as average of rumble's * 2/3 of strong magnitude and 1/3 of weak magnitude */ magnitude = effect->u.rumble.strong_magnitude / 3 + effect->u.rumble.weak_magnitude / 6; effect->type = FF_PERIODIC; effect->u.periodic.waveform = FF_SINE; effect->u.periodic.period = 50; effect->u.periodic.magnitude = max(magnitude, 0x7fff); effect->u.periodic.offset = 0; effect->u.periodic.phase = 0; effect->u.periodic.envelope.attack_length = 0; effect->u.periodic.envelope.attack_level = 0; effect->u.periodic.envelope.fade_length = 0; effect->u.periodic.envelope.fade_level = 0; return 0; default: /* Let driver handle conversion */ return 0; } } /** * input_ff_upload() - upload effect into force-feedback device * @dev: input device * @effect: effect to be uploaded * @file: owner of the effect */ int input_ff_upload(struct input_dev *dev, struct ff_effect *effect, struct file *file) { struct ff_device *ff = dev->ff; struct ff_effect *old; int ret = 0; int id; if (!test_bit(EV_FF, dev->evbit)) return -ENOSYS; if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX || !test_bit(effect->type, dev->ffbit)) { debug("invalid or not supported effect type in upload"); return -EINVAL; } if (effect->type == FF_PERIODIC && (effect->u.periodic.waveform < FF_WAVEFORM_MIN || effect->u.periodic.waveform > FF_WAVEFORM_MAX || !test_bit(effect->u.periodic.waveform, dev->ffbit))) { debug("invalid or not supported wave form in upload"); return -EINVAL; } if (!test_bit(effect->type, ff->ffbit)) { ret = compat_effect(ff, effect); if (ret) return ret; } mutex_lock(&ff->mutex); if (effect->id == -1) { for (id = 0; id < ff->max_effects; id++) if (!ff->effect_owners[id]) break; if (id >= ff->max_effects) { ret = -ENOSPC; goto out; } effect->id = id; old = NULL; } else { id = effect->id; ret = check_effect_access(ff, id, file); if (ret) goto out; old = &ff->effects[id]; if (!check_effects_compatible(effect, old)) { ret = -EINVAL; goto out; } } ret = ff->upload(dev, effect, old); if (ret) goto out; ff->effects[id] = *effect; ff->effect_owners[id] = file; out: mutex_unlock(&ff->mutex); return ret; } EXPORT_SYMBOL_GPL(input_ff_upload); /* * Erases the effect if the requester is also the effect owner. The mutex * should already be locked before calling this function. */ static int erase_effect(struct input_dev *dev, int effect_id, struct file *file) { struct ff_device *ff = dev->ff; int error; error = check_effect_access(ff, effect_id, file); if (error) return error; ff->playback(dev, effect_id, 0); if (ff->erase) { error = ff->erase(dev, effect_id); if (error) return error; } ff->effect_owners[effect_id] = NULL; return 0; } /** * input_ff_erase - erase a force-feedback effect from device * @dev: input device to erase effect from * @effect_id: id of the ffect to be erased * @file: purported owner of the request * * This function erases a force-feedback effect from specified device. * The effect will only be erased if it was uploaded through the same * file handle that is requesting erase. */ int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file) { struct ff_device *ff = dev->ff; int ret; if (!test_bit(EV_FF, dev->evbit)) return -ENOSYS; mutex_lock(&ff->mutex); ret = erase_effect(dev, effect_id, file); mutex_unlock(&ff->mutex); return ret; } EXPORT_SYMBOL_GPL(input_ff_erase); /* * flush_effects - erase all effects owned by a file handle */ static int flush_effects(struct input_dev *dev, struct file *file) { struct ff_device *ff = dev->ff; int i; debug("flushing now"); mutex_lock(&ff->mutex); for (i = 0; i < ff->max_effects; i++) erase_effect(dev, i, file); mutex_unlock(&ff->mutex); return 0; } /** * input_ff_event() - generic handler for force-feedback events * @dev: input device to send the effect to * @type: event type (anything but EV_FF is ignored) * @code: event code * @value: event value */ int input_ff_event(struct input_dev *dev, unsigned int type, unsigned int code, int value) { struct ff_device *ff = dev->ff; if (type != EV_FF) return 0; mutex_lock(&ff->mutex); switch (code) { case FF_GAIN: if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffff) break; ff->set_gain(dev, value); break; case FF_AUTOCENTER: if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffff) break; ff->set_autocenter(dev, value); break; default: if (check_effect_access(ff, code, NULL) == 0) ff->playback(dev, code, value); break; } mutex_unlock(&ff->mutex); return 0; } EXPORT_SYMBOL_GPL(input_ff_event); /** * input_ff_create() - create force-feedback device * @dev: input device supporting force-feedback * @max_effects: maximum number of effects supported by the device * * This function allocates all necessary memory for a force feedback * portion of an input device and installs all default handlers. * @dev->ffbit should be already set up before calling this function. * Once ff device is created you need to setup its upload, erase, * playback and other handlers before registering input device */ int input_ff_create(struct input_dev *dev, int max_effects) { struct ff_device *ff; int i; if (!max_effects) { printk(KERN_ERR "ff-core: cannot allocate device without any effects\n"); return -EINVAL; } ff = kzalloc(sizeof(struct ff_device) + max_effects * sizeof(struct file *), GFP_KERNEL); if (!ff) return -ENOMEM; ff->effects = kcalloc(max_effects, sizeof(struct ff_effect), GFP_KERNEL); if (!ff->effects) { kfree(ff); return -ENOMEM; } ff->max_effects = max_effects; mutex_init(&ff->mutex); dev->ff = ff; dev->flush = flush_effects; dev->event = input_ff_event; set_bit(EV_FF, dev->evbit); /* Copy "true" bits into ff device bitmap */ for (i = 0; i <= FF_MAX; i++) if (test_bit(i, dev->ffbit)) set_bit(i, ff->ffbit); /* we can emulate RUMBLE with periodic effects */ if (test_bit(FF_PERIODIC, ff->ffbit)) set_bit(FF_RUMBLE, dev->ffbit); return 0; } EXPORT_SYMBOL_GPL(input_ff_create); /** * input_ff_free() - frees force feedback portion of input device * @dev: input device supporting force feedback * * This function is only needed in error path as input core will * automatically free force feedback structures when device is * destroyed. */ void input_ff_destroy(struct input_dev *dev) { clear_bit(EV_FF, dev->evbit); if (dev->ff) { if (dev->ff->destroy) dev->ff->destroy(dev->ff); kfree(dev->ff->private); kfree(dev->ff); dev->ff = NULL; } } EXPORT_SYMBOL_GPL(input_ff_destroy);