/*
* Copyright © 2018 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include "config.h"
#include "evdev.h"
enum totem_slot_state {
SLOT_STATE_NONE,
SLOT_STATE_BEGIN,
SLOT_STATE_UPDATE,
SLOT_STATE_END,
};
struct totem_slot {
bool dirty;
unsigned int index;
enum totem_slot_state state;
struct libinput_tablet_tool *tool;
struct tablet_axes axes;
unsigned char changed_axes[NCHARS(LIBINPUT_TABLET_TOOL_AXIS_MAX + 1)];
struct device_coords last_point;
};
struct totem_dispatch {
struct evdev_dispatch base;
struct evdev_device *device;
int slot; /* current slot */
struct totem_slot *slots;
size_t nslots;
struct evdev_device *touch_device;
/* We only have one button */
bool button_state_now;
bool button_state_previous;
enum evdev_arbitration_state arbitration_state;
};
static inline struct totem_dispatch*
totem_dispatch(struct evdev_dispatch *totem)
{
evdev_verify_dispatch_type(totem, DISPATCH_TOTEM);
return container_of(totem, struct totem_dispatch, base);
}
static inline struct libinput *
totem_libinput_context(const struct totem_dispatch *totem)
{
return evdev_libinput_context(totem->device);
}
static struct libinput_tablet_tool *
totem_new_tool(struct totem_dispatch *totem)
{
struct libinput *libinput = totem_libinput_context(totem);
struct libinput_tablet_tool *tool;
tool = zalloc(sizeof *tool);
*tool = (struct libinput_tablet_tool) {
.type = LIBINPUT_TABLET_TOOL_TYPE_TOTEM,
.serial = 0,
.tool_id = 0,
.refcount = 1,
};
tool->pressure_offset = 0;
tool->has_pressure_offset = false;
tool->pressure_threshold.lower = 0;
tool->pressure_threshold.upper = 1;
set_bit(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_X);
set_bit(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_Y);
set_bit(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
set_bit(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_SIZE_MAJOR);
set_bit(tool->axis_caps, LIBINPUT_TABLET_TOOL_AXIS_SIZE_MINOR);
set_bit(tool->buttons, BTN_0);
list_insert(&libinput->tool_list, &tool->link);
return tool;
}
static inline void
totem_set_touch_device_enabled(struct totem_dispatch *totem,
bool enable_touch_device,
uint64_t time)
{
struct evdev_device *touch_device = totem->touch_device;
struct evdev_dispatch *dispatch;
struct phys_rect r, *rect = NULL;
enum evdev_arbitration_state state = ARBITRATION_NOT_ACTIVE;
if (touch_device == NULL)
return;
/* We just pick the coordinates of the first touch we find. The
* totem only does one tool right now despite being nominally an MT
* device, so let's not go too hard on ourselves*/
for (size_t i = 0; !enable_touch_device && i < totem->nslots; i++) {
struct totem_slot *slot = &totem->slots[i];
struct phys_coords mm;
if (slot->state == SLOT_STATE_NONE)
continue;
/* Totem size is ~70mm. We could calculate the real size but
until we need that, hardcoding it is enough */
mm = evdev_device_units_to_mm(totem->device, &slot->axes.point);
r.x = mm.x - 30;
r.y = mm.y - 30;
r.w = 100;
r.h = 100;
rect = &r;
state = ARBITRATION_IGNORE_RECT;
break;
}
dispatch = touch_device->dispatch;
if (enable_touch_device) {
if (dispatch->interface->touch_arbitration_toggle)
dispatch->interface->touch_arbitration_toggle(dispatch,
touch_device,
state,
rect,
time);
} else {
switch (totem->arbitration_state) {
case ARBITRATION_IGNORE_ALL:
abort();
case ARBITRATION_NOT_ACTIVE:
if (dispatch->interface->touch_arbitration_toggle)
dispatch->interface->touch_arbitration_toggle(dispatch,
touch_device,
state,
rect,
time);
break;
case ARBITRATION_IGNORE_RECT:
if (dispatch->interface->touch_arbitration_update_rect)
dispatch->interface->touch_arbitration_update_rect(dispatch,
touch_device,
rect,
time);
break;
}
}
totem->arbitration_state = state;
}
static void
totem_process_key(struct totem_dispatch *totem,
struct evdev_device *device,
struct input_event *e,
uint64_t time)
{
switch(e->code) {
case BTN_0:
totem->button_state_now = !!e->value;
break;
default:
evdev_log_info(device,
"Unhandled KEY event code %#x\n",
e->code);
break;
}
}
static void
totem_process_abs(struct totem_dispatch *totem,
struct evdev_device *device,
struct input_event *e,
uint64_t time)
{
struct totem_slot *slot = &totem->slots[totem->slot];
switch(e->code) {
case ABS_MT_SLOT:
if ((size_t)e->value >= totem->nslots) {
evdev_log_bug_libinput(device,
"exceeded slot count (%d of max %zd)\n",
e->value,
totem->nslots);
e->value = totem->nslots - 1;
}
totem->slot = e->value;
return;
case ABS_MT_TRACKING_ID:
/* If the totem is already down on init, we currently
ignore it */
if (e->value >= 0)
slot->state = SLOT_STATE_BEGIN;
else if (slot->state != SLOT_STATE_NONE)
slot->state = SLOT_STATE_END;
break;
case ABS_MT_POSITION_X:
set_bit(slot->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_X);
break;
case ABS_MT_POSITION_Y:
set_bit(slot->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_Y);
break;
case ABS_MT_TOUCH_MAJOR:
set_bit(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_SIZE_MAJOR);
break;
case ABS_MT_TOUCH_MINOR:
set_bit(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_SIZE_MINOR);
break;
case ABS_MT_ORIENTATION:
set_bit(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z);
break;
case ABS_MT_TOOL_TYPE:
if (e->value != MT_TOOL_DIAL) {
evdev_log_info(device,
"Unexpected tool type %#x, changing to dial\n",
e->code);
}
break;
default:
evdev_log_info(device,
"Unhandled ABS event code %#x\n",
e->code);
break;
}
}
static bool
totem_slot_fetch_axes(struct totem_dispatch *totem,
struct totem_slot *slot,
struct libinput_tablet_tool *tool,
struct tablet_axes *axes_out,
uint64_t time)
{
struct evdev_device *device = totem->device;
const char tmp[sizeof(slot->changed_axes)] = {0};
struct tablet_axes axes = {0};
struct device_float_coords delta;
bool rc = false;
if (memcmp(tmp, slot->changed_axes, sizeof(tmp)) == 0) {
axes = slot->axes;
goto out;
}
if (bit_is_set(slot->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_X) ||
bit_is_set(slot->changed_axes, LIBINPUT_TABLET_TOOL_AXIS_Y)) {
slot->axes.point.x = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_POSITION_X);
slot->axes.point.y = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_POSITION_Y);
}
if (bit_is_set(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_ROTATION_Z)) {
int angle = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_ORIENTATION);
/* The kernel gives us ±90 degrees off neutral */
slot->axes.rotation = (360 - angle) % 360;
}
if (bit_is_set(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_SIZE_MAJOR) ||
bit_is_set(slot->changed_axes,
LIBINPUT_TABLET_TOOL_AXIS_SIZE_MINOR)) {
int major, minor;
unsigned int rmajor, rminor;
major = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_TOUCH_MAJOR);
minor = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_TOUCH_MINOR);
rmajor = libevdev_get_abs_resolution(device->evdev, ABS_MT_TOUCH_MAJOR);
rminor = libevdev_get_abs_resolution(device->evdev, ABS_MT_TOUCH_MINOR);
slot->axes.size.major = (double)major/rmajor;
slot->axes.size.minor = (double)minor/rminor;
}
axes.point = slot->axes.point;
axes.rotation = slot->axes.rotation;
axes.size = slot->axes.size;
delta.x = slot->axes.point.x - slot->last_point.x;
delta.y = slot->axes.point.y - slot->last_point.y;
axes.delta = filter_dispatch(device->pointer.filter, &delta, tool, time);
rc = true;
out:
*axes_out = axes;
return rc;
}
static void
totem_slot_mark_all_axes_changed(struct totem_dispatch *totem,
struct totem_slot *slot,
struct libinput_tablet_tool *tool)
{
static_assert(sizeof(slot->changed_axes) ==
sizeof(tool->axis_caps),
"Mismatching array sizes");
memcpy(slot->changed_axes,
tool->axis_caps,
sizeof(slot->changed_axes));
}
static inline void
totem_slot_reset_changed_axes(struct totem_dispatch *totem,
struct totem_slot *slot)
{
memset(slot->changed_axes, 0, sizeof(slot->changed_axes));
}
static inline void
slot_axes_initialize(struct totem_dispatch *totem,
struct totem_slot *slot)
{
struct evdev_device *device = totem->device;
slot->axes.point.x = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_POSITION_X);
slot->axes.point.y = libevdev_get_slot_value(device->evdev,
slot->index,
ABS_MT_POSITION_Y);
slot->last_point.x = slot->axes.point.x;
slot->last_point.y = slot->axes.point.y;
}
static enum totem_slot_state
totem_handle_slot_state(struct totem_dispatch *totem,
struct totem_slot *slot,
uint64_t time)
{
struct evdev_device *device = totem->device;
struct tablet_axes axes;
enum libinput_tablet_tool_tip_state tip_state;
bool updated;
switch (slot->state) {
case SLOT_STATE_BEGIN:
if (!slot->tool)
slot->tool = totem_new_tool(totem);
slot_axes_initialize(totem, slot);
totem_slot_mark_all_axes_changed(totem, slot, slot->tool);
break;
case SLOT_STATE_UPDATE:
case SLOT_STATE_END:
assert(slot->tool);
break;
case SLOT_STATE_NONE:
return SLOT_STATE_NONE;
}
tip_state = LIBINPUT_TABLET_TOOL_TIP_UP;
updated = totem_slot_fetch_axes(totem, slot, slot->tool, &axes, time);
switch (slot->state) {
case SLOT_STATE_BEGIN:
tip_state = LIBINPUT_TABLET_TOOL_TIP_DOWN;
tablet_notify_proximity(&device->base,
time,
slot->tool,
LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_IN,
slot->changed_axes,
&axes);
totem_slot_reset_changed_axes(totem, slot);
tablet_notify_tip(&device->base,
time,
slot->tool,
tip_state,
slot->changed_axes,
&axes);
slot->state = SLOT_STATE_UPDATE;
break;
case SLOT_STATE_UPDATE:
tip_state = LIBINPUT_TABLET_TOOL_TIP_DOWN;
if (updated) {
tablet_notify_axis(&device->base,
time,
slot->tool,
tip_state,
slot->changed_axes,
&axes);
}
break;
case SLOT_STATE_END:
/* prox out is handled after button events */
break;
case SLOT_STATE_NONE:
abort();
break;
}
/* We only have one button but possibly multiple totems. It's not
* clear how the firmware will work, so for now we just handle the
* button state in the first slot.
*
* Due to the design of the totem we're also less fancy about
* button handling than the tablet code. Worst case, you might get
* tip up before button up but meh.
*/
if (totem->button_state_now != totem->button_state_previous) {
enum libinput_button_state btn_state;
if (totem->button_state_now)
btn_state = LIBINPUT_BUTTON_STATE_PRESSED;
else
btn_state = LIBINPUT_BUTTON_STATE_RELEASED;
tablet_notify_button(&device->base,
time,
slot->tool,
tip_state,
&axes,
BTN_0,
btn_state);
totem->button_state_previous = totem->button_state_now;
}
switch(slot->state) {
case SLOT_STATE_BEGIN:
case SLOT_STATE_UPDATE:
break;
case SLOT_STATE_END:
tip_state = LIBINPUT_TABLET_TOOL_TIP_UP;
tablet_notify_tip(&device->base,
time,
slot->tool,
tip_state,
slot->changed_axes,
&axes);
totem_slot_reset_changed_axes(totem, slot);
tablet_notify_proximity(&device->base,
time,
slot->tool,
LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_OUT,
slot->changed_axes,
&axes);
slot->state = SLOT_STATE_NONE;
break;
case SLOT_STATE_NONE:
abort();
break;
}
slot->last_point = slot->axes.point;
totem_slot_reset_changed_axes(totem, slot);
return slot->state;
}
static enum totem_slot_state
totem_handle_state(struct totem_dispatch *totem,
uint64_t time)
{
enum totem_slot_state global_state = SLOT_STATE_NONE;
for (size_t i = 0; i < totem->nslots; i++) {
enum totem_slot_state s;
s = totem_handle_slot_state(totem,
&totem->slots[i],
time);
/* If one slot is active, the totem is active */
if (s != SLOT_STATE_NONE)
global_state = SLOT_STATE_UPDATE;
}
return global_state;
}
static void
totem_interface_process(struct evdev_dispatch *dispatch,
struct evdev_device *device,
struct input_event *e,
uint64_t time)
{
struct totem_dispatch *totem = totem_dispatch(dispatch);
enum totem_slot_state global_state;
bool enable_touch;
switch(e->type) {
case EV_ABS:
totem_process_abs(totem, device, e, time);
break;
case EV_KEY:
totem_process_key(totem, device, e, time);
break;
case EV_MSC:
/* timestamp, ignore */
break;
case EV_SYN:
global_state = totem_handle_state(totem, time);
enable_touch = (global_state == SLOT_STATE_NONE);
totem_set_touch_device_enabled(totem,
enable_touch,
time);
break;
default:
evdev_log_error(device,
"Unexpected event type %s (%#x)\n",
libevdev_event_type_get_name(e->type),
e->type);
break;
}
}
static void
totem_interface_suspend(struct evdev_dispatch *dispatch,
struct evdev_device *device)
{
struct totem_dispatch *totem = totem_dispatch(dispatch);
uint64_t now = libinput_now(evdev_libinput_context(device));
for (size_t i = 0; i < totem->nslots; i++) {
struct totem_slot *slot = &totem->slots[i];
struct tablet_axes axes;
enum libinput_tablet_tool_tip_state tip_state;
/* If we never initialized a tool, we can skip everything */
if (!slot->tool)
continue;
totem_slot_fetch_axes(totem, slot, slot->tool, &axes, now);
totem_slot_reset_changed_axes(totem, slot);
if (slot->state == SLOT_STATE_NONE)
tip_state = LIBINPUT_TABLET_TOOL_TIP_UP;
else
tip_state = LIBINPUT_TABLET_TOOL_TIP_DOWN;
if (totem->button_state_now) {
tablet_notify_button(&device->base,
now,
slot->tool,
tip_state,
&axes,
BTN_0,
LIBINPUT_BUTTON_STATE_RELEASED);
totem->button_state_now = false;
totem->button_state_previous = false;
}
if (slot->state != SLOT_STATE_NONE) {
tablet_notify_tip(&device->base,
now,
slot->tool,
LIBINPUT_TABLET_TOOL_TIP_UP,
slot->changed_axes,
&axes);
}
tablet_notify_proximity(&device->base,
now,
slot->tool,
LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_OUT,
slot->changed_axes,
&axes);
}
totem_set_touch_device_enabled(totem, true, now);
}
static void
totem_interface_destroy(struct evdev_dispatch *dispatch)
{
struct totem_dispatch *totem = totem_dispatch(dispatch);
free(totem->slots);
free(totem);
}
static void
totem_interface_device_added(struct evdev_device *device,
struct evdev_device *added_device)
{
struct totem_dispatch *totem = totem_dispatch(device->dispatch);
struct libinput_device_group *g1, *g2;
if ((evdev_device_get_id_vendor(added_device) !=
evdev_device_get_id_vendor(device)) ||
(evdev_device_get_id_product(added_device) !=
evdev_device_get_id_product(device)))
return;
/* virtual devices don't have device groups, so check for that
libinput replay */
g1 = libinput_device_get_device_group(&device->base);
g2 = libinput_device_get_device_group(&added_device->base);
if (g1 && g2 && g1->identifier != g2->identifier)
return;
if (totem->touch_device != NULL) {
evdev_log_bug_libinput(device,
"already has a paired touch device, ignoring (%s)\n",
added_device->devname);
return;
}
totem->touch_device = added_device;
evdev_log_info(device, "%s: is the totem touch device\n", added_device->devname);
}
static void
totem_interface_device_removed(struct evdev_device *device,
struct evdev_device *removed_device)
{
struct totem_dispatch *totem = totem_dispatch(device->dispatch);
if (totem->touch_device != removed_device)
return;
totem_set_touch_device_enabled(totem, true,
libinput_now(evdev_libinput_context(device)));
totem->touch_device = NULL;
}
static void
totem_interface_initial_proximity(struct evdev_device *device,
struct evdev_dispatch *dispatch)
{
struct totem_dispatch *totem = totem_dispatch(dispatch);
uint64_t now = libinput_now(evdev_libinput_context(device));
bool enable_touch = true;
for (size_t i = 0; i < totem->nslots; i++) {
struct totem_slot *slot = &totem->slots[i];
struct tablet_axes axes;
int tracking_id;
tracking_id = libevdev_get_slot_value(device->evdev,
i,
ABS_MT_TRACKING_ID);
if (tracking_id == -1)
continue;
slot->tool = totem_new_tool(totem);
slot_axes_initialize(totem, slot);
totem_slot_mark_all_axes_changed(totem, slot, slot->tool);
totem_slot_fetch_axes(totem, slot, slot->tool, &axes, now);
tablet_notify_proximity(&device->base,
now,
slot->tool,
LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_IN,
slot->changed_axes,
&axes);
totem_slot_reset_changed_axes(totem, slot);
tablet_notify_tip(&device->base,
now,
slot->tool,
LIBINPUT_TABLET_TOOL_TIP_DOWN,
slot->changed_axes,
&axes);
slot->state = SLOT_STATE_UPDATE;
enable_touch = false;
}
totem_set_touch_device_enabled(totem, enable_touch, now);
}
struct evdev_dispatch_interface totem_interface = {
.process = totem_interface_process,
.suspend = totem_interface_suspend,
.remove = NULL,
.destroy = totem_interface_destroy,
.device_added = totem_interface_device_added,
.device_removed = totem_interface_device_removed,
.device_suspended = totem_interface_device_added, /* treat as remove */
.device_resumed = totem_interface_device_removed, /* treat as add */
.post_added = totem_interface_initial_proximity,
.touch_arbitration_toggle = NULL,
.touch_arbitration_update_rect = NULL,
.get_switch_state = NULL,
};
static bool
totem_reject_device(struct evdev_device *device)
{
struct libevdev *evdev = device->evdev;
bool has_xy, has_slot, has_tool_dial, has_size;
double w, h;
has_xy = libevdev_has_event_code(evdev, EV_ABS, ABS_MT_POSITION_X) &&
libevdev_has_event_code(evdev, EV_ABS, ABS_MT_POSITION_Y);
has_slot = libevdev_has_event_code(evdev, EV_ABS, ABS_MT_SLOT);
has_tool_dial = libevdev_has_event_code(evdev, EV_ABS, ABS_MT_TOOL_TYPE) &&
libevdev_get_abs_maximum(evdev, ABS_MT_TOOL_TYPE) >= MT_TOOL_DIAL;
has_size = evdev_device_get_size(device, &w, &h) == 0;
has_size |= libevdev_get_abs_resolution(device->evdev, ABS_MT_TOUCH_MAJOR) > 0;
has_size |= libevdev_get_abs_resolution(device->evdev, ABS_MT_TOUCH_MINOR) > 0;
if (has_xy && has_slot && has_tool_dial && has_size)
return false;
evdev_log_bug_libinput(device,
"missing totem capabilities:%s%s%s%s. "
"Ignoring this device.\n",
has_xy ? "" : " xy",
has_slot ? "" : " slot",
has_tool_dial ? "" : " dial",
has_size ? "" : " resolutions");
return true;
}
static uint32_t
totem_accel_config_get_profiles(struct libinput_device *libinput_device)
{
return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}
static enum libinput_config_status
totem_accel_config_set_profile(struct libinput_device *libinput_device,
enum libinput_config_accel_profile profile)
{
return LIBINPUT_CONFIG_STATUS_UNSUPPORTED;
}
static enum libinput_config_accel_profile
totem_accel_config_get_profile(struct libinput_device *libinput_device)
{
return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}
static enum libinput_config_accel_profile
totem_accel_config_get_default_profile(struct libinput_device *libinput_device)
{
return LIBINPUT_CONFIG_ACCEL_PROFILE_NONE;
}
static int
totem_init_accel(struct totem_dispatch *totem, struct evdev_device *device)
{
const struct input_absinfo *x, *y;
struct motion_filter *filter;
x = device->abs.absinfo_x;
y = device->abs.absinfo_y;
/* same filter as the tablet */
filter = create_pointer_accelerator_filter_tablet(x->resolution,
y->resolution);
if (!filter)
return -1;
evdev_device_init_pointer_acceleration(device, filter);
/* we override the profile hooks for accel configuration with hooks
* that don't allow selection of profiles */
device->pointer.config.get_profiles = totem_accel_config_get_profiles;
device->pointer.config.set_profile = totem_accel_config_set_profile;
device->pointer.config.get_profile = totem_accel_config_get_profile;
device->pointer.config.get_default_profile = totem_accel_config_get_default_profile;
return 0;
}
struct evdev_dispatch *
evdev_totem_create(struct evdev_device *device)
{
struct totem_dispatch *totem;
struct totem_slot *slots;
int num_slots;
if (totem_reject_device(device))
return NULL;
totem = zalloc(sizeof *totem);
totem->device = device;
totem->base.dispatch_type = DISPATCH_TOTEM;
totem->base.interface = &totem_interface;
num_slots = libevdev_get_num_slots(device->evdev);
if (num_slots <= 0)
goto error;
totem->slot = libevdev_get_current_slot(device->evdev);
slots = zalloc(num_slots * sizeof(*totem->slots));
for (int slot = 0; slot < num_slots; ++slot) {
slots[slot].index = slot;
}
totem->slots = slots;
totem->nslots = num_slots;
evdev_init_sendevents(device, &totem->base);
totem_init_accel(totem, device);
return &totem->base;
error:
totem_interface_destroy(&totem->base);
return NULL;
}