linux/drivers/input/ff-memless.c
Mauro Carvalho Chehab 559addc25b [media] fixp-arith: replace sin/cos table by a better precision one
The cos table used at fixp-arith.h has only 8 bits of precision.
That causes problems if it is reused on other drivers.

As some media drivers require a higher precision sin/cos
implementation, replace the current implementation by one that
will provide 32 bits precision.

The values generated by the new implementation matches the
32 bit precision of glibc's sin for an angle measured in
integer degrees.

It also provides support for fractional angles via linear
interpolation. On experimental calculus, when used a table
with a 0.001 degree angle, the maximum error for sin is
0.000038, which is likely good enough for practical purposes.

There are some logic there that seems to be specific to the
usage inside ff-memless.c. Move those logic to there, as they're
not needed elsewhere.

Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Prashant Laddha <prladdha@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2015-03-02 14:50:06 -03:00

560 lines
14 KiB
C

/*
* Force feedback support for memoryless devices
*
* 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 pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/fixp-arith.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Anssi Hannula <anssi.hannula@gmail.com>");
MODULE_DESCRIPTION("Force feedback support for memoryless devices");
/* Number of effects handled with memoryless devices */
#define FF_MEMLESS_EFFECTS 16
/* Envelope update interval in ms */
#define FF_ENVELOPE_INTERVAL 50
#define FF_EFFECT_STARTED 0
#define FF_EFFECT_PLAYING 1
#define FF_EFFECT_ABORTING 2
struct ml_effect_state {
struct ff_effect *effect;
unsigned long flags; /* effect state (STARTED, PLAYING, etc) */
int count; /* loop count of the effect */
unsigned long play_at; /* start time */
unsigned long stop_at; /* stop time */
unsigned long adj_at; /* last time the effect was sent */
};
struct ml_device {
void *private;
struct ml_effect_state states[FF_MEMLESS_EFFECTS];
int gain;
struct timer_list timer;
struct input_dev *dev;
int (*play_effect)(struct input_dev *dev, void *data,
struct ff_effect *effect);
};
static const struct ff_envelope *get_envelope(const struct ff_effect *effect)
{
static const struct ff_envelope empty_envelope;
switch (effect->type) {
case FF_PERIODIC:
return &effect->u.periodic.envelope;
case FF_CONSTANT:
return &effect->u.constant.envelope;
default:
return &empty_envelope;
}
}
/*
* Check for the next time envelope requires an update on memoryless devices
*/
static unsigned long calculate_next_time(struct ml_effect_state *state)
{
const struct ff_envelope *envelope = get_envelope(state->effect);
unsigned long attack_stop, fade_start, next_fade;
if (envelope->attack_length) {
attack_stop = state->play_at +
msecs_to_jiffies(envelope->attack_length);
if (time_before(state->adj_at, attack_stop))
return state->adj_at +
msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
}
if (state->effect->replay.length) {
if (envelope->fade_length) {
/* check when fading should start */
fade_start = state->stop_at -
msecs_to_jiffies(envelope->fade_length);
if (time_before(state->adj_at, fade_start))
return fade_start;
/* already fading, advance to next checkpoint */
next_fade = state->adj_at +
msecs_to_jiffies(FF_ENVELOPE_INTERVAL);
if (time_before(next_fade, state->stop_at))
return next_fade;
}
return state->stop_at;
}
return state->play_at;
}
static void ml_schedule_timer(struct ml_device *ml)
{
struct ml_effect_state *state;
unsigned long now = jiffies;
unsigned long earliest = 0;
unsigned long next_at;
int events = 0;
int i;
pr_debug("calculating next timer\n");
for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
state = &ml->states[i];
if (!test_bit(FF_EFFECT_STARTED, &state->flags))
continue;
if (test_bit(FF_EFFECT_PLAYING, &state->flags))
next_at = calculate_next_time(state);
else
next_at = state->play_at;
if (time_before_eq(now, next_at) &&
(++events == 1 || time_before(next_at, earliest)))
earliest = next_at;
}
if (!events) {
pr_debug("no actions\n");
del_timer(&ml->timer);
} else {
pr_debug("timer set\n");
mod_timer(&ml->timer, earliest);
}
}
/*
* Apply an envelope to a value
*/
static int apply_envelope(struct ml_effect_state *state, int value,
struct ff_envelope *envelope)
{
struct ff_effect *effect = state->effect;
unsigned long now = jiffies;
int time_from_level;
int time_of_envelope;
int envelope_level;
int difference;
if (envelope->attack_length &&
time_before(now,
state->play_at + msecs_to_jiffies(envelope->attack_length))) {
pr_debug("value = 0x%x, attack_level = 0x%x\n",
value, envelope->attack_level);
time_from_level = jiffies_to_msecs(now - state->play_at);
time_of_envelope = envelope->attack_length;
envelope_level = min_t(u16, envelope->attack_level, 0x7fff);
} else if (envelope->fade_length && effect->replay.length &&
time_after(now,
state->stop_at - msecs_to_jiffies(envelope->fade_length)) &&
time_before(now, state->stop_at)) {
time_from_level = jiffies_to_msecs(state->stop_at - now);
time_of_envelope = envelope->fade_length;
envelope_level = min_t(u16, envelope->fade_level, 0x7fff);
} else
return value;
difference = abs(value) - envelope_level;
pr_debug("difference = %d\n", difference);
pr_debug("time_from_level = 0x%x\n", time_from_level);
pr_debug("time_of_envelope = 0x%x\n", time_of_envelope);
difference = difference * time_from_level / time_of_envelope;
pr_debug("difference = %d\n", difference);
return value < 0 ?
-(difference + envelope_level) : (difference + envelope_level);
}
/*
* Return the type the effect has to be converted into (memless devices)
*/
static int get_compatible_type(struct ff_device *ff, int effect_type)
{
if (test_bit(effect_type, ff->ffbit))
return effect_type;
if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit))
return FF_RUMBLE;
pr_err("invalid type in get_compatible_type()\n");
return 0;
}
/*
* Only left/right direction should be used (under/over 0x8000) for
* forward/reverse motor direction (to keep calculation fast & simple).
*/
static u16 ml_calculate_direction(u16 direction, u16 force,
u16 new_direction, u16 new_force)
{
if (!force)
return new_direction;
if (!new_force)
return direction;
return (((u32)(direction >> 1) * force +
(new_direction >> 1) * new_force) /
(force + new_force)) << 1;
}
#define FRAC_N 8
static inline s16 fixp_new16(s16 a)
{
return ((s32)a) >> (16 - FRAC_N);
}
static inline s16 fixp_mult(s16 a, s16 b)
{
a = ((s32)a * 0x100) / 0x7fff;
return ((s32)(a * b)) >> FRAC_N;
}
/*
* Combine two effects and apply gain.
*/
static void ml_combine_effects(struct ff_effect *effect,
struct ml_effect_state *state,
int gain)
{
struct ff_effect *new = state->effect;
unsigned int strong, weak, i;
int x, y;
s16 level;
switch (new->type) {
case FF_CONSTANT:
i = new->direction * 360 / 0xffff;
level = fixp_new16(apply_envelope(state,
new->u.constant.level,
&new->u.constant.envelope));
x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff;
y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff;
/*
* here we abuse ff_ramp to hold x and y of constant force
* If in future any driver wants something else than x and y
* in s8, this should be changed to something more generic
*/
effect->u.ramp.start_level =
clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f);
effect->u.ramp.end_level =
clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f);
break;
case FF_RUMBLE:
strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff;
weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff;
if (effect->u.rumble.strong_magnitude + strong)
effect->direction = ml_calculate_direction(
effect->direction,
effect->u.rumble.strong_magnitude,
new->direction, strong);
else if (effect->u.rumble.weak_magnitude + weak)
effect->direction = ml_calculate_direction(
effect->direction,
effect->u.rumble.weak_magnitude,
new->direction, weak);
else
effect->direction = 0;
effect->u.rumble.strong_magnitude =
min(strong + effect->u.rumble.strong_magnitude,
0xffffU);
effect->u.rumble.weak_magnitude =
min(weak + effect->u.rumble.weak_magnitude, 0xffffU);
break;
case FF_PERIODIC:
i = apply_envelope(state, abs(new->u.periodic.magnitude),
&new->u.periodic.envelope);
/* here we also scale it 0x7fff => 0xffff */
i = i * gain / 0x7fff;
if (effect->u.rumble.strong_magnitude + i)
effect->direction = ml_calculate_direction(
effect->direction,
effect->u.rumble.strong_magnitude,
new->direction, i);
else
effect->direction = 0;
effect->u.rumble.strong_magnitude =
min(i + effect->u.rumble.strong_magnitude, 0xffffU);
effect->u.rumble.weak_magnitude =
min(i + effect->u.rumble.weak_magnitude, 0xffffU);
break;
default:
pr_err("invalid type in ml_combine_effects()\n");
break;
}
}
/*
* Because memoryless devices have only one effect per effect type active
* at one time we have to combine multiple effects into one
*/
static int ml_get_combo_effect(struct ml_device *ml,
unsigned long *effect_handled,
struct ff_effect *combo_effect)
{
struct ff_effect *effect;
struct ml_effect_state *state;
int effect_type;
int i;
memset(combo_effect, 0, sizeof(struct ff_effect));
for (i = 0; i < FF_MEMLESS_EFFECTS; i++) {
if (__test_and_set_bit(i, effect_handled))
continue;
state = &ml->states[i];
effect = state->effect;
if (!test_bit(FF_EFFECT_STARTED, &state->flags))
continue;
if (time_before(jiffies, state->play_at))
continue;
/*
* here we have started effects that are either
* currently playing (and may need be aborted)
* or need to start playing.
*/
effect_type = get_compatible_type(ml->dev->ff, effect->type);
if (combo_effect->type != effect_type) {
if (combo_effect->type != 0) {
__clear_bit(i, effect_handled);
continue;
}
combo_effect->type = effect_type;
}
if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) {
__clear_bit(FF_EFFECT_PLAYING, &state->flags);
__clear_bit(FF_EFFECT_STARTED, &state->flags);
} else if (effect->replay.length &&
time_after_eq(jiffies, state->stop_at)) {
__clear_bit(FF_EFFECT_PLAYING, &state->flags);
if (--state->count <= 0) {
__clear_bit(FF_EFFECT_STARTED, &state->flags);
} else {
state->play_at = jiffies +
msecs_to_jiffies(effect->replay.delay);
state->stop_at = state->play_at +
msecs_to_jiffies(effect->replay.length);
}
} else {
__set_bit(FF_EFFECT_PLAYING, &state->flags);
state->adj_at = jiffies;
ml_combine_effects(combo_effect, state, ml->gain);
}
}
return combo_effect->type != 0;
}
static void ml_play_effects(struct ml_device *ml)
{
struct ff_effect effect;
DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS);
memset(handled_bm, 0, sizeof(handled_bm));
while (ml_get_combo_effect(ml, handled_bm, &effect))
ml->play_effect(ml->dev, ml->private, &effect);
ml_schedule_timer(ml);
}
static void ml_effect_timer(unsigned long timer_data)
{
struct input_dev *dev = (struct input_dev *)timer_data;
struct ml_device *ml = dev->ff->private;
unsigned long flags;
pr_debug("timer: updating effects\n");
spin_lock_irqsave(&dev->event_lock, flags);
ml_play_effects(ml);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
/*
* Sets requested gain for FF effects. Called with dev->event_lock held.
*/
static void ml_ff_set_gain(struct input_dev *dev, u16 gain)
{
struct ml_device *ml = dev->ff->private;
int i;
ml->gain = gain;
for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
__clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags);
ml_play_effects(ml);
}
/*
* Start/stop specified FF effect. Called with dev->event_lock held.
*/
static int ml_ff_playback(struct input_dev *dev, int effect_id, int value)
{
struct ml_device *ml = dev->ff->private;
struct ml_effect_state *state = &ml->states[effect_id];
if (value > 0) {
pr_debug("initiated play\n");
__set_bit(FF_EFFECT_STARTED, &state->flags);
state->count = value;
state->play_at = jiffies +
msecs_to_jiffies(state->effect->replay.delay);
state->stop_at = state->play_at +
msecs_to_jiffies(state->effect->replay.length);
state->adj_at = state->play_at;
} else {
pr_debug("initiated stop\n");
if (test_bit(FF_EFFECT_PLAYING, &state->flags))
__set_bit(FF_EFFECT_ABORTING, &state->flags);
else
__clear_bit(FF_EFFECT_STARTED, &state->flags);
}
ml_play_effects(ml);
return 0;
}
static int ml_ff_upload(struct input_dev *dev,
struct ff_effect *effect, struct ff_effect *old)
{
struct ml_device *ml = dev->ff->private;
struct ml_effect_state *state = &ml->states[effect->id];
spin_lock_irq(&dev->event_lock);
if (test_bit(FF_EFFECT_STARTED, &state->flags)) {
__clear_bit(FF_EFFECT_PLAYING, &state->flags);
state->play_at = jiffies +
msecs_to_jiffies(state->effect->replay.delay);
state->stop_at = state->play_at +
msecs_to_jiffies(state->effect->replay.length);
state->adj_at = state->play_at;
ml_schedule_timer(ml);
}
spin_unlock_irq(&dev->event_lock);
return 0;
}
static void ml_ff_destroy(struct ff_device *ff)
{
struct ml_device *ml = ff->private;
kfree(ml->private);
}
/**
* input_ff_create_memless() - create memoryless force-feedback device
* @dev: input device supporting force-feedback
* @data: driver-specific data to be passed into @play_effect
* @play_effect: driver-specific method for playing FF effect
*/
int input_ff_create_memless(struct input_dev *dev, void *data,
int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
{
struct ml_device *ml;
struct ff_device *ff;
int error;
int i;
ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL);
if (!ml)
return -ENOMEM;
ml->dev = dev;
ml->private = data;
ml->play_effect = play_effect;
ml->gain = 0xffff;
setup_timer(&ml->timer, ml_effect_timer, (unsigned long)dev);
set_bit(FF_GAIN, dev->ffbit);
error = input_ff_create(dev, FF_MEMLESS_EFFECTS);
if (error) {
kfree(ml);
return error;
}
ff = dev->ff;
ff->private = ml;
ff->upload = ml_ff_upload;
ff->playback = ml_ff_playback;
ff->set_gain = ml_ff_set_gain;
ff->destroy = ml_ff_destroy;
/* we can emulate periodic effects with RUMBLE */
if (test_bit(FF_RUMBLE, ff->ffbit)) {
set_bit(FF_PERIODIC, dev->ffbit);
set_bit(FF_SINE, dev->ffbit);
set_bit(FF_TRIANGLE, dev->ffbit);
set_bit(FF_SQUARE, dev->ffbit);
}
for (i = 0; i < FF_MEMLESS_EFFECTS; i++)
ml->states[i].effect = &ff->effects[i];
return 0;
}
EXPORT_SYMBOL_GPL(input_ff_create_memless);