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556 lines
14 KiB
556 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Force feedback support for memoryless devices |
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* |
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* Copyright (c) 2006 Anssi Hannula <[email protected]> |
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* Copyright (c) 2006 Dmitry Torokhov <[email protected]> |
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*/ |
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/* |
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*/ |
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/* #define DEBUG */ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/slab.h> |
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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/spinlock.h> |
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#include <linux/jiffies.h> |
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#include <linux/fixp-arith.h> |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Anssi Hannula <[email protected]>"); |
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MODULE_DESCRIPTION("Force feedback support for memoryless devices"); |
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/* Number of effects handled with memoryless devices */ |
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#define FF_MEMLESS_EFFECTS 16 |
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/* Envelope update interval in ms */ |
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#define FF_ENVELOPE_INTERVAL 50 |
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#define FF_EFFECT_STARTED 0 |
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#define FF_EFFECT_PLAYING 1 |
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#define FF_EFFECT_ABORTING 2 |
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struct ml_effect_state { |
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struct ff_effect *effect; |
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unsigned long flags; /* effect state (STARTED, PLAYING, etc) */ |
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int count; /* loop count of the effect */ |
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unsigned long play_at; /* start time */ |
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unsigned long stop_at; /* stop time */ |
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unsigned long adj_at; /* last time the effect was sent */ |
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}; |
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struct ml_device { |
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void *private; |
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struct ml_effect_state states[FF_MEMLESS_EFFECTS]; |
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int gain; |
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struct timer_list timer; |
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struct input_dev *dev; |
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int (*play_effect)(struct input_dev *dev, void *data, |
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struct ff_effect *effect); |
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}; |
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static const struct ff_envelope *get_envelope(const struct ff_effect *effect) |
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{ |
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static const struct ff_envelope empty_envelope; |
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switch (effect->type) { |
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case FF_PERIODIC: |
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return &effect->u.periodic.envelope; |
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case FF_CONSTANT: |
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return &effect->u.constant.envelope; |
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default: |
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return &empty_envelope; |
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} |
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} |
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/* |
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* Check for the next time envelope requires an update on memoryless devices |
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*/ |
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static unsigned long calculate_next_time(struct ml_effect_state *state) |
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{ |
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const struct ff_envelope *envelope = get_envelope(state->effect); |
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unsigned long attack_stop, fade_start, next_fade; |
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if (envelope->attack_length) { |
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attack_stop = state->play_at + |
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msecs_to_jiffies(envelope->attack_length); |
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if (time_before(state->adj_at, attack_stop)) |
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return state->adj_at + |
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msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
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} |
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if (state->effect->replay.length) { |
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if (envelope->fade_length) { |
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/* check when fading should start */ |
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fade_start = state->stop_at - |
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msecs_to_jiffies(envelope->fade_length); |
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if (time_before(state->adj_at, fade_start)) |
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return fade_start; |
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/* already fading, advance to next checkpoint */ |
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next_fade = state->adj_at + |
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msecs_to_jiffies(FF_ENVELOPE_INTERVAL); |
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if (time_before(next_fade, state->stop_at)) |
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return next_fade; |
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} |
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return state->stop_at; |
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} |
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return state->play_at; |
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} |
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static void ml_schedule_timer(struct ml_device *ml) |
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{ |
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struct ml_effect_state *state; |
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unsigned long now = jiffies; |
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unsigned long earliest = 0; |
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unsigned long next_at; |
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int events = 0; |
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int i; |
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pr_debug("calculating next timer\n"); |
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for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
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state = &ml->states[i]; |
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if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
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continue; |
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if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
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next_at = calculate_next_time(state); |
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else |
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next_at = state->play_at; |
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if (time_before_eq(now, next_at) && |
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(++events == 1 || time_before(next_at, earliest))) |
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earliest = next_at; |
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} |
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if (!events) { |
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pr_debug("no actions\n"); |
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del_timer(&ml->timer); |
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} else { |
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pr_debug("timer set\n"); |
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mod_timer(&ml->timer, earliest); |
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} |
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} |
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/* |
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* Apply an envelope to a value |
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*/ |
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static int apply_envelope(struct ml_effect_state *state, int value, |
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struct ff_envelope *envelope) |
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{ |
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struct ff_effect *effect = state->effect; |
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unsigned long now = jiffies; |
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int time_from_level; |
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int time_of_envelope; |
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int envelope_level; |
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int difference; |
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if (envelope->attack_length && |
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time_before(now, |
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state->play_at + msecs_to_jiffies(envelope->attack_length))) { |
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pr_debug("value = 0x%x, attack_level = 0x%x\n", |
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value, envelope->attack_level); |
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time_from_level = jiffies_to_msecs(now - state->play_at); |
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time_of_envelope = envelope->attack_length; |
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envelope_level = min_t(u16, envelope->attack_level, 0x7fff); |
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} else if (envelope->fade_length && effect->replay.length && |
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time_after(now, |
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state->stop_at - msecs_to_jiffies(envelope->fade_length)) && |
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time_before(now, state->stop_at)) { |
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time_from_level = jiffies_to_msecs(state->stop_at - now); |
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time_of_envelope = envelope->fade_length; |
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envelope_level = min_t(u16, envelope->fade_level, 0x7fff); |
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} else |
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return value; |
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difference = abs(value) - envelope_level; |
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pr_debug("difference = %d\n", difference); |
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pr_debug("time_from_level = 0x%x\n", time_from_level); |
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pr_debug("time_of_envelope = 0x%x\n", time_of_envelope); |
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difference = difference * time_from_level / time_of_envelope; |
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pr_debug("difference = %d\n", difference); |
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return value < 0 ? |
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-(difference + envelope_level) : (difference + envelope_level); |
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} |
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/* |
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* Return the type the effect has to be converted into (memless devices) |
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*/ |
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static int get_compatible_type(struct ff_device *ff, int effect_type) |
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{ |
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if (test_bit(effect_type, ff->ffbit)) |
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return effect_type; |
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if (effect_type == FF_PERIODIC && test_bit(FF_RUMBLE, ff->ffbit)) |
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return FF_RUMBLE; |
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pr_err("invalid type in get_compatible_type()\n"); |
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return 0; |
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} |
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/* |
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* Only left/right direction should be used (under/over 0x8000) for |
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* forward/reverse motor direction (to keep calculation fast & simple). |
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*/ |
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static u16 ml_calculate_direction(u16 direction, u16 force, |
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u16 new_direction, u16 new_force) |
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{ |
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if (!force) |
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return new_direction; |
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if (!new_force) |
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return direction; |
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return (((u32)(direction >> 1) * force + |
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(new_direction >> 1) * new_force) / |
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(force + new_force)) << 1; |
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} |
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#define FRAC_N 8 |
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static inline s16 fixp_new16(s16 a) |
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{ |
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return ((s32)a) >> (16 - FRAC_N); |
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} |
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static inline s16 fixp_mult(s16 a, s16 b) |
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{ |
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a = ((s32)a * 0x100) / 0x7fff; |
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return ((s32)(a * b)) >> FRAC_N; |
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} |
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/* |
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* Combine two effects and apply gain. |
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*/ |
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static void ml_combine_effects(struct ff_effect *effect, |
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struct ml_effect_state *state, |
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int gain) |
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{ |
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struct ff_effect *new = state->effect; |
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unsigned int strong, weak, i; |
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int x, y; |
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s16 level; |
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switch (new->type) { |
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case FF_CONSTANT: |
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i = new->direction * 360 / 0xffff; |
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level = fixp_new16(apply_envelope(state, |
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new->u.constant.level, |
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&new->u.constant.envelope)); |
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x = fixp_mult(fixp_sin16(i), level) * gain / 0xffff; |
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y = fixp_mult(-fixp_cos16(i), level) * gain / 0xffff; |
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/* |
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* here we abuse ff_ramp to hold x and y of constant force |
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* If in future any driver wants something else than x and y |
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* in s8, this should be changed to something more generic |
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*/ |
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effect->u.ramp.start_level = |
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clamp_val(effect->u.ramp.start_level + x, -0x80, 0x7f); |
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effect->u.ramp.end_level = |
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clamp_val(effect->u.ramp.end_level + y, -0x80, 0x7f); |
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break; |
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case FF_RUMBLE: |
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strong = (u32)new->u.rumble.strong_magnitude * gain / 0xffff; |
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weak = (u32)new->u.rumble.weak_magnitude * gain / 0xffff; |
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if (effect->u.rumble.strong_magnitude + strong) |
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effect->direction = ml_calculate_direction( |
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effect->direction, |
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effect->u.rumble.strong_magnitude, |
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new->direction, strong); |
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else if (effect->u.rumble.weak_magnitude + weak) |
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effect->direction = ml_calculate_direction( |
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effect->direction, |
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effect->u.rumble.weak_magnitude, |
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new->direction, weak); |
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else |
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effect->direction = 0; |
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effect->u.rumble.strong_magnitude = |
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min(strong + effect->u.rumble.strong_magnitude, |
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0xffffU); |
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effect->u.rumble.weak_magnitude = |
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min(weak + effect->u.rumble.weak_magnitude, 0xffffU); |
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break; |
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case FF_PERIODIC: |
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i = apply_envelope(state, abs(new->u.periodic.magnitude), |
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&new->u.periodic.envelope); |
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/* here we also scale it 0x7fff => 0xffff */ |
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i = i * gain / 0x7fff; |
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if (effect->u.rumble.strong_magnitude + i) |
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effect->direction = ml_calculate_direction( |
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effect->direction, |
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effect->u.rumble.strong_magnitude, |
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new->direction, i); |
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else |
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effect->direction = 0; |
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effect->u.rumble.strong_magnitude = |
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min(i + effect->u.rumble.strong_magnitude, 0xffffU); |
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effect->u.rumble.weak_magnitude = |
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min(i + effect->u.rumble.weak_magnitude, 0xffffU); |
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break; |
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default: |
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pr_err("invalid type in ml_combine_effects()\n"); |
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break; |
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} |
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} |
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/* |
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* Because memoryless devices have only one effect per effect type active |
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* at one time we have to combine multiple effects into one |
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*/ |
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static int ml_get_combo_effect(struct ml_device *ml, |
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unsigned long *effect_handled, |
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struct ff_effect *combo_effect) |
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{ |
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struct ff_effect *effect; |
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struct ml_effect_state *state; |
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int effect_type; |
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int i; |
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memset(combo_effect, 0, sizeof(struct ff_effect)); |
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for (i = 0; i < FF_MEMLESS_EFFECTS; i++) { |
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if (__test_and_set_bit(i, effect_handled)) |
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continue; |
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state = &ml->states[i]; |
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effect = state->effect; |
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if (!test_bit(FF_EFFECT_STARTED, &state->flags)) |
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continue; |
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if (time_before(jiffies, state->play_at)) |
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continue; |
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/* |
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* here we have started effects that are either |
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* currently playing (and may need be aborted) |
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* or need to start playing. |
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*/ |
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effect_type = get_compatible_type(ml->dev->ff, effect->type); |
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if (combo_effect->type != effect_type) { |
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if (combo_effect->type != 0) { |
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__clear_bit(i, effect_handled); |
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continue; |
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} |
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combo_effect->type = effect_type; |
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} |
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if (__test_and_clear_bit(FF_EFFECT_ABORTING, &state->flags)) { |
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__clear_bit(FF_EFFECT_PLAYING, &state->flags); |
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__clear_bit(FF_EFFECT_STARTED, &state->flags); |
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} else if (effect->replay.length && |
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time_after_eq(jiffies, state->stop_at)) { |
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__clear_bit(FF_EFFECT_PLAYING, &state->flags); |
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if (--state->count <= 0) { |
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__clear_bit(FF_EFFECT_STARTED, &state->flags); |
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} else { |
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state->play_at = jiffies + |
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msecs_to_jiffies(effect->replay.delay); |
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state->stop_at = state->play_at + |
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msecs_to_jiffies(effect->replay.length); |
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} |
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} else { |
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__set_bit(FF_EFFECT_PLAYING, &state->flags); |
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state->adj_at = jiffies; |
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ml_combine_effects(combo_effect, state, ml->gain); |
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} |
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} |
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return combo_effect->type != 0; |
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} |
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static void ml_play_effects(struct ml_device *ml) |
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{ |
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struct ff_effect effect; |
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DECLARE_BITMAP(handled_bm, FF_MEMLESS_EFFECTS); |
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memset(handled_bm, 0, sizeof(handled_bm)); |
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while (ml_get_combo_effect(ml, handled_bm, &effect)) |
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ml->play_effect(ml->dev, ml->private, &effect); |
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ml_schedule_timer(ml); |
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} |
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static void ml_effect_timer(struct timer_list *t) |
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{ |
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struct ml_device *ml = from_timer(ml, t, timer); |
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struct input_dev *dev = ml->dev; |
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unsigned long flags; |
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pr_debug("timer: updating effects\n"); |
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spin_lock_irqsave(&dev->event_lock, flags); |
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ml_play_effects(ml); |
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spin_unlock_irqrestore(&dev->event_lock, flags); |
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} |
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/* |
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* Sets requested gain for FF effects. Called with dev->event_lock held. |
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*/ |
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static void ml_ff_set_gain(struct input_dev *dev, u16 gain) |
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{ |
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struct ml_device *ml = dev->ff->private; |
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int i; |
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ml->gain = gain; |
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for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
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__clear_bit(FF_EFFECT_PLAYING, &ml->states[i].flags); |
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ml_play_effects(ml); |
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} |
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/* |
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* Start/stop specified FF effect. Called with dev->event_lock held. |
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*/ |
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static int ml_ff_playback(struct input_dev *dev, int effect_id, int value) |
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{ |
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struct ml_device *ml = dev->ff->private; |
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struct ml_effect_state *state = &ml->states[effect_id]; |
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if (value > 0) { |
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pr_debug("initiated play\n"); |
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__set_bit(FF_EFFECT_STARTED, &state->flags); |
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state->count = value; |
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state->play_at = jiffies + |
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msecs_to_jiffies(state->effect->replay.delay); |
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state->stop_at = state->play_at + |
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msecs_to_jiffies(state->effect->replay.length); |
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state->adj_at = state->play_at; |
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} else { |
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pr_debug("initiated stop\n"); |
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if (test_bit(FF_EFFECT_PLAYING, &state->flags)) |
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__set_bit(FF_EFFECT_ABORTING, &state->flags); |
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else |
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__clear_bit(FF_EFFECT_STARTED, &state->flags); |
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} |
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ml_play_effects(ml); |
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return 0; |
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} |
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static int ml_ff_upload(struct input_dev *dev, |
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struct ff_effect *effect, struct ff_effect *old) |
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{ |
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struct ml_device *ml = dev->ff->private; |
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struct ml_effect_state *state = &ml->states[effect->id]; |
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spin_lock_irq(&dev->event_lock); |
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if (test_bit(FF_EFFECT_STARTED, &state->flags)) { |
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__clear_bit(FF_EFFECT_PLAYING, &state->flags); |
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state->play_at = jiffies + |
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msecs_to_jiffies(state->effect->replay.delay); |
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state->stop_at = state->play_at + |
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msecs_to_jiffies(state->effect->replay.length); |
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state->adj_at = state->play_at; |
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ml_schedule_timer(ml); |
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} |
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spin_unlock_irq(&dev->event_lock); |
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return 0; |
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} |
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static void ml_ff_destroy(struct ff_device *ff) |
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{ |
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struct ml_device *ml = ff->private; |
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/* |
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* Even though we stop all playing effects when tearing down |
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* an input device (via input_device_flush() that calls into |
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* input_ff_flush() that stops and erases all effects), we |
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* do not actually stop the timer, and therefore we should |
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* do it here. |
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*/ |
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del_timer_sync(&ml->timer); |
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kfree(ml->private); |
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} |
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/** |
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* input_ff_create_memless() - create memoryless force-feedback device |
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* @dev: input device supporting force-feedback |
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* @data: driver-specific data to be passed into @play_effect |
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* @play_effect: driver-specific method for playing FF effect |
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*/ |
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int input_ff_create_memless(struct input_dev *dev, void *data, |
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int (*play_effect)(struct input_dev *, void *, struct ff_effect *)) |
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{ |
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struct ml_device *ml; |
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struct ff_device *ff; |
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int error; |
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int i; |
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ml = kzalloc(sizeof(struct ml_device), GFP_KERNEL); |
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if (!ml) |
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return -ENOMEM; |
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ml->dev = dev; |
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ml->private = data; |
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ml->play_effect = play_effect; |
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ml->gain = 0xffff; |
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timer_setup(&ml->timer, ml_effect_timer, 0); |
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set_bit(FF_GAIN, dev->ffbit); |
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error = input_ff_create(dev, FF_MEMLESS_EFFECTS); |
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if (error) { |
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kfree(ml); |
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return error; |
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} |
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ff = dev->ff; |
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ff->private = ml; |
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ff->upload = ml_ff_upload; |
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ff->playback = ml_ff_playback; |
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ff->set_gain = ml_ff_set_gain; |
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ff->destroy = ml_ff_destroy; |
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/* we can emulate periodic effects with RUMBLE */ |
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if (test_bit(FF_RUMBLE, ff->ffbit)) { |
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set_bit(FF_PERIODIC, dev->ffbit); |
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set_bit(FF_SINE, dev->ffbit); |
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set_bit(FF_TRIANGLE, dev->ffbit); |
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set_bit(FF_SQUARE, dev->ffbit); |
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} |
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for (i = 0; i < FF_MEMLESS_EFFECTS; i++) |
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ml->states[i].effect = &ff->effects[i]; |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(input_ff_create_memless);
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