110 lines
2.4 KiB
C
110 lines
2.4 KiB
C
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/**
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* SPDX-License-Identifier: GPL-3.0-or-later
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*/
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#include "force_feedback.h"
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#include "log.h"
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#include <linux/input.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#include <libudev.h>
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#include <stdint.h>
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#include <unistd.h>
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#define bit_is_set(array, bit) ((array[bit / 8] >> bit % 8) & 0x01)
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/**
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* Static variables
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*/
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static int fd = -1;
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static struct input_event ff_event = {
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.type = EV_FF,
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.code = 0,
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.value = 1
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};
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/**
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* Public functions
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*/
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void bbx_force_feedback_connect(struct udev_device* device) {
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if (fd >= 0)
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return;
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const char* node = udev_device_get_devnode(device);
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int fd_event = open(node, O_RDWR);
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if (fd_event < 0) {
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bbx_log(BBX_LOG_LEVEL_ERROR, "Can't open %s", node);
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return;
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}
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int n_effects;
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if (ioctl(fd_event, EVIOCGEFFECTS, &n_effects) == -1 || n_effects == 0) {
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close(fd_event);
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return;
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}
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bbx_log(BBX_LOG_LEVEL_VERBOSE, "Found a force feedback device: %s", node);
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uint8_t features[(FF_CNT + 7) / 8];
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if (ioctl(fd_event, EVIOCGBIT(EV_FF, sizeof(features)), features) == -1) {
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bbx_log(BBX_LOG_LEVEL_ERROR, "Can't request features of %s", node);
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close(fd_event);
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return;
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}
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if (!bit_is_set(features, FF_RUMBLE)) {
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bbx_log(BBX_LOG_LEVEL_VERBOSE, "%s does not support FF_RUMBLE", node);
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close(fd_event);
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return;
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}
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struct ff_effect effect = {
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.type = FF_RUMBLE,
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.id = -1,
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.direction = 0x0000,
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.trigger.button = 0,
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.trigger.interval = 0,
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.replay.length = 50,
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.replay.delay = 0,
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.u.rumble.strong_magnitude = 0xC000,
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.u.rumble.weak_magnitude = 0xC000
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};
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if (ioctl(fd_event, EVIOCSFF, &effect) == -1) {
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bbx_log(BBX_LOG_LEVEL_ERROR, "Can't upload the effect");
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close(fd_event);
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return;
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}
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ff_event.code = effect.id;
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if (bit_is_set(features, FF_GAIN)) {
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struct input_event gain = {
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.type = EV_FF,
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.code = FF_GAIN,
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.value = 0xFFFF
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};
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if (write(fd_event, &gain, sizeof(gain)) != sizeof(gain))
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bbx_log(BBX_LOG_LEVEL_WARNING, "Can't set the gain");
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}
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fd = fd_event;
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}
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void bbx_force_feedback_play() {
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if (fd < 0)
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return;
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if (write(fd, &ff_event, sizeof(ff_event)) != sizeof(ff_event)) {
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// Assume that the force feedback device was disconnected
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close(fd);
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fd = -1;
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}
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}
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