Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  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);