380 lines
8.7 KiB
C
380 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Force feedback support for Linux input subsystem
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*
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* Copyright (c) 2006 Anssi Hannula <anssi.hannula@gmail.com>
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* Copyright (c) 2006 Dmitry Torokhov <dtor@mail.ru>
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*/
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/*
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*/
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/* #define DEBUG */
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#include <linux/input.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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/*
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* Check that the effect_id is a valid effect and whether the user
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* is the owner
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*/
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static int check_effect_access(struct ff_device *ff, int effect_id,
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struct file *file)
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{
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if (effect_id < 0 || effect_id >= ff->max_effects ||
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!ff->effect_owners[effect_id])
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return -EINVAL;
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if (file && ff->effect_owners[effect_id] != file)
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return -EACCES;
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return 0;
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}
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/*
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* Checks whether 2 effects can be combined together
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*/
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static inline int check_effects_compatible(struct ff_effect *e1,
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struct ff_effect *e2)
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{
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return e1->type == e2->type &&
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(e1->type != FF_PERIODIC ||
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e1->u.periodic.waveform == e2->u.periodic.waveform);
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}
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/*
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* Convert an effect into compatible one
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*/
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static int compat_effect(struct ff_device *ff, struct ff_effect *effect)
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{
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int magnitude;
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switch (effect->type) {
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case FF_RUMBLE:
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if (!test_bit(FF_PERIODIC, ff->ffbit))
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return -EINVAL;
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/*
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* calculate magnitude of sine wave as average of rumble's
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* 2/3 of strong magnitude and 1/3 of weak magnitude
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*/
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magnitude = effect->u.rumble.strong_magnitude / 3 +
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effect->u.rumble.weak_magnitude / 6;
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effect->type = FF_PERIODIC;
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effect->u.periodic.waveform = FF_SINE;
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effect->u.periodic.period = 50;
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effect->u.periodic.magnitude = max(magnitude, 0x7fff);
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effect->u.periodic.offset = 0;
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effect->u.periodic.phase = 0;
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effect->u.periodic.envelope.attack_length = 0;
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effect->u.periodic.envelope.attack_level = 0;
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effect->u.periodic.envelope.fade_length = 0;
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effect->u.periodic.envelope.fade_level = 0;
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return 0;
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default:
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/* Let driver handle conversion */
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return 0;
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}
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}
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/**
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* input_ff_upload() - upload effect into force-feedback device
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* @dev: input device
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* @effect: effect to be uploaded
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* @file: owner of the effect
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*/
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int input_ff_upload(struct input_dev *dev, struct ff_effect *effect,
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struct file *file)
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{
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struct ff_device *ff = dev->ff;
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struct ff_effect *old;
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int ret = 0;
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int id;
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if (!test_bit(EV_FF, dev->evbit))
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return -ENOSYS;
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if (effect->type < FF_EFFECT_MIN || effect->type > FF_EFFECT_MAX ||
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!test_bit(effect->type, dev->ffbit)) {
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dev_dbg(&dev->dev, "invalid or not supported effect type in upload\n");
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return -EINVAL;
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}
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if (effect->type == FF_PERIODIC &&
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(effect->u.periodic.waveform < FF_WAVEFORM_MIN ||
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effect->u.periodic.waveform > FF_WAVEFORM_MAX ||
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!test_bit(effect->u.periodic.waveform, dev->ffbit))) {
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dev_dbg(&dev->dev, "invalid or not supported wave form in upload\n");
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return -EINVAL;
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}
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if (!test_bit(effect->type, ff->ffbit)) {
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ret = compat_effect(ff, effect);
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if (ret)
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return ret;
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}
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mutex_lock(&ff->mutex);
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if (effect->id == -1) {
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for (id = 0; id < ff->max_effects; id++)
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if (!ff->effect_owners[id])
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break;
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if (id >= ff->max_effects) {
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ret = -ENOSPC;
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goto out;
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}
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effect->id = id;
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old = NULL;
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} else {
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id = effect->id;
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ret = check_effect_access(ff, id, file);
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if (ret)
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goto out;
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old = &ff->effects[id];
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if (!check_effects_compatible(effect, old)) {
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ret = -EINVAL;
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goto out;
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}
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}
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ret = ff->upload(dev, effect, old);
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if (ret)
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goto out;
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spin_lock_irq(&dev->event_lock);
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ff->effects[id] = *effect;
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ff->effect_owners[id] = file;
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spin_unlock_irq(&dev->event_lock);
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out:
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mutex_unlock(&ff->mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(input_ff_upload);
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/*
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* Erases the effect if the requester is also the effect owner. The mutex
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* should already be locked before calling this function.
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*/
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static int erase_effect(struct input_dev *dev, int effect_id,
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struct file *file)
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{
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struct ff_device *ff = dev->ff;
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int error;
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error = check_effect_access(ff, effect_id, file);
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if (error)
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return error;
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spin_lock_irq(&dev->event_lock);
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ff->playback(dev, effect_id, 0);
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ff->effect_owners[effect_id] = NULL;
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spin_unlock_irq(&dev->event_lock);
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if (ff->erase) {
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error = ff->erase(dev, effect_id);
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if (error) {
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spin_lock_irq(&dev->event_lock);
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ff->effect_owners[effect_id] = file;
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spin_unlock_irq(&dev->event_lock);
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return error;
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}
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}
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return 0;
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}
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/**
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* input_ff_erase - erase a force-feedback effect from device
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* @dev: input device to erase effect from
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* @effect_id: id of the effect to be erased
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* @file: purported owner of the request
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*
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* This function erases a force-feedback effect from specified device.
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* The effect will only be erased if it was uploaded through the same
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* file handle that is requesting erase.
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*/
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int input_ff_erase(struct input_dev *dev, int effect_id, struct file *file)
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{
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struct ff_device *ff = dev->ff;
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int ret;
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if (!test_bit(EV_FF, dev->evbit))
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return -ENOSYS;
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mutex_lock(&ff->mutex);
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ret = erase_effect(dev, effect_id, file);
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mutex_unlock(&ff->mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(input_ff_erase);
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/*
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* input_ff_flush - erase all effects owned by a file handle
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* @dev: input device to erase effect from
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* @file: purported owner of the effects
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*
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* This function erases all force-feedback effects associated with
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* the given owner from specified device. Note that @file may be %NULL,
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* in which case all effects will be erased.
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*/
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int input_ff_flush(struct input_dev *dev, struct file *file)
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{
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struct ff_device *ff = dev->ff;
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int i;
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dev_dbg(&dev->dev, "flushing now\n");
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mutex_lock(&ff->mutex);
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for (i = 0; i < ff->max_effects; i++)
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erase_effect(dev, i, file);
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mutex_unlock(&ff->mutex);
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return 0;
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}
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EXPORT_SYMBOL_GPL(input_ff_flush);
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/**
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* input_ff_event() - generic handler for force-feedback events
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* @dev: input device to send the effect to
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* @type: event type (anything but EV_FF is ignored)
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* @code: event code
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* @value: event value
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*/
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int input_ff_event(struct input_dev *dev, unsigned int type,
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unsigned int code, int value)
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{
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struct ff_device *ff = dev->ff;
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if (type != EV_FF)
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return 0;
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switch (code) {
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case FF_GAIN:
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if (!test_bit(FF_GAIN, dev->ffbit) || value > 0xffffU)
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break;
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ff->set_gain(dev, value);
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break;
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case FF_AUTOCENTER:
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if (!test_bit(FF_AUTOCENTER, dev->ffbit) || value > 0xffffU)
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break;
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ff->set_autocenter(dev, value);
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break;
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default:
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if (check_effect_access(ff, code, NULL) == 0)
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ff->playback(dev, code, value);
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break;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(input_ff_event);
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/**
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* input_ff_create() - create force-feedback device
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* @dev: input device supporting force-feedback
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* @max_effects: maximum number of effects supported by the device
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*
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* This function allocates all necessary memory for a force feedback
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* portion of an input device and installs all default handlers.
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* @dev->ffbit should be already set up before calling this function.
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* Once ff device is created you need to setup its upload, erase,
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* playback and other handlers before registering input device
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*/
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int input_ff_create(struct input_dev *dev, unsigned int max_effects)
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{
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struct ff_device *ff;
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size_t ff_dev_size;
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int i;
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if (!max_effects) {
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dev_err(&dev->dev, "cannot allocate device without any effects\n");
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return -EINVAL;
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}
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if (max_effects > FF_MAX_EFFECTS) {
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dev_err(&dev->dev, "cannot allocate more than FF_MAX_EFFECTS effects\n");
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return -EINVAL;
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}
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ff_dev_size = sizeof(struct ff_device) +
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max_effects * sizeof(struct file *);
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if (ff_dev_size < max_effects) /* overflow */
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return -EINVAL;
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ff = kzalloc(ff_dev_size, GFP_KERNEL);
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if (!ff)
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return -ENOMEM;
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ff->effects = kcalloc(max_effects, sizeof(struct ff_effect),
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GFP_KERNEL);
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if (!ff->effects) {
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kfree(ff);
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return -ENOMEM;
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}
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ff->max_effects = max_effects;
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mutex_init(&ff->mutex);
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dev->ff = ff;
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dev->flush = input_ff_flush;
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dev->event = input_ff_event;
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__set_bit(EV_FF, dev->evbit);
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/* Copy "true" bits into ff device bitmap */
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for_each_set_bit(i, dev->ffbit, FF_CNT)
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__set_bit(i, ff->ffbit);
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/* we can emulate RUMBLE with periodic effects */
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if (test_bit(FF_PERIODIC, ff->ffbit))
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__set_bit(FF_RUMBLE, dev->ffbit);
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return 0;
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}
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EXPORT_SYMBOL_GPL(input_ff_create);
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/**
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* input_ff_destroy() - frees force feedback portion of input device
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* @dev: input device supporting force feedback
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*
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* This function is only needed in error path as input core will
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* automatically free force feedback structures when device is
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* destroyed.
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*/
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void input_ff_destroy(struct input_dev *dev)
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{
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struct ff_device *ff = dev->ff;
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__clear_bit(EV_FF, dev->evbit);
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if (ff) {
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if (ff->destroy)
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ff->destroy(ff);
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kfree(ff->private);
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kfree(ff->effects);
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kfree(ff);
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dev->ff = NULL;
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}
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}
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EXPORT_SYMBOL_GPL(input_ff_destroy);
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