linux-imx

/*

 *  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 */

​

#include <linux/input.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/sched.h>

#include <linux/slab.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 magnitude 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: