play_effect
play_effect(hdev, haptic, &haptic->stop_effect);
play_effect(hdev, haptic, effect);
error = input_ff_create_memless(dev, lg2ff, play_effect);
int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
ret = input_ff_create_memless(haptics, NULL, play_effect);
int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
if (play_effect) {
ret = input_ff_create_memless(gamepad, NULL, play_effect);
ml->play_effect(ml->dev, ml->private, &effect);
int (*play_effect)(struct input_dev *, void *, struct ff_effect *))
ml->play_effect = play_effect;
int (*play_effect)(struct input_dev *dev, void *data,
int (*play_effect)(struct input_dev *, void *, struct ff_effect *));