accelerometer.c revision e239cd8de06a62c9adc71ff1329a1ce76e8735a5
/*
* accelerometer - exports device orientation through property
*
* When an "change" event is received on an accelerometer,
* open its device node, and from the value, as well as the previous
* value of the property, calculate the device's new orientation,
* and export it as ID_INPUT_ACCELEROMETER_ORIENTATION.
*
* Possible values are:
* undefined
* * normal
* * bottom-up
* * left-up
* * right-up
*
* The property will be persistent across sessions, and the new
* orientations can be deducted from the previous one (it allows
* for a threshold for switching between opposite ends of the
* orientation).
*
* Copyright (C) 2011 Red Hat, Inc.
* Author:
* Bastien Nocera <hadess@hadess.net>
*
* orientation_calc() from the sensorfw package
* Copyright (C) 2009-2010 Nokia Corporation
* Authors:
* Üstün Ergenoglu <ext-ustun.ergenoglu@nokia.com>
* Timo Rongas <ext-timo.2.rongas@nokia.com>
* Lihan Guo <lihan.guo@digia.com>
*
* 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 keymap; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <limits.h>
#include <linux/limits.h>
#include <linux/input.h>
#include "libudev.h"
#include "libudev-private.h"
/* we must use this kernel-compatible implementation */
#define BITS_PER_LONG (sizeof(unsigned long) * 8)
#define NBITS(x) ((((x)-1)/BITS_PER_LONG)+1)
#define OFF(x) ((x)%BITS_PER_LONG)
#define BIT(x) (1UL<<OFF(x))
#define LONG(x) ((x)/BITS_PER_LONG)
#define test_bit(bit, array) ((array[LONG(bit)] >> OFF(bit)) & 1)
static int debug = 0;
static void log_fn(struct udev *udev, int priority,
const char *file, int line, const char *fn,
const char *format, va_list args)
{
if (debug) {
fprintf(stderr, "%s: ", fn);
vfprintf(stderr, format, args);
} else {
vsyslog(priority, format, args);
}
}
typedef enum {
ORIENTATION_UNDEFINED,
ORIENTATION_NORMAL,
ORIENTATION_BOTTOM_UP,
ORIENTATION_LEFT_UP,
ORIENTATION_RIGHT_UP
} OrientationUp;
static const char *orientations[] = {
"undefined",
"normal",
"bottom-up",
"left-up",
"right-up",
NULL
};
#define ORIENTATION_UP_UP ORIENTATION_NORMAL
#define DEFAULT_THRESHOLD 250
#define RADIANS_TO_DEGREES 180.0/M_PI
#define SAME_AXIS_LIMIT 5
#define THRESHOLD_LANDSCAPE 25
#define THRESHOLD_PORTRAIT 20
static const char *
orientation_to_string (OrientationUp o)
{
return orientations[o];
}
static OrientationUp
string_to_orientation (const char *orientation)
{
int i;
if (orientation == NULL)
return ORIENTATION_UNDEFINED;
for (i = 0; orientations[i] != NULL; i++) {
if (strcmp (orientation, orientations[i]) == 0)
return i;
}
return ORIENTATION_UNDEFINED;
}
static OrientationUp
orientation_calc (OrientationUp prev,
int x, int y, int z)
{
int rotation;
OrientationUp ret = prev;
/* Portrait check */
rotation = round(atan((double) x / sqrt(y * y + z * z)) * RADIANS_TO_DEGREES);
if (abs(rotation) > THRESHOLD_PORTRAIT) {
ret = (rotation < 0) ? ORIENTATION_LEFT_UP : ORIENTATION_RIGHT_UP;
/* Some threshold to switching between portrait modes */
if (prev == ORIENTATION_LEFT_UP || prev == ORIENTATION_RIGHT_UP) {
if (abs(rotation) < SAME_AXIS_LIMIT) {
ret = prev;
}
}
} else {
/* Landscape check */
rotation = round(atan((double) y / sqrt(x * x + z * z)) * RADIANS_TO_DEGREES);
if (abs(rotation) > THRESHOLD_LANDSCAPE) {
ret = (rotation < 0) ? ORIENTATION_BOTTOM_UP : ORIENTATION_NORMAL;
/* Some threshold to switching between landscape modes */
if (prev == ORIENTATION_BOTTOM_UP || prev == ORIENTATION_NORMAL) {
if (abs(rotation) < SAME_AXIS_LIMIT) {
ret = prev;
}
}
}
}
return ret;
}
static OrientationUp
get_prev_orientation(struct udev_device *dev)
{
const char *value;
value = udev_device_get_property_value(dev, "ID_INPUT_ACCELEROMETER_ORIENTATION");
if (value == NULL)
return ORIENTATION_UNDEFINED;
return string_to_orientation(value);
}
#define SET_AXIS(axis, code_) if (ev[i].code == code_) { if (got_##axis == 0) { axis = ev[i].value; got_##axis = 1; } }
/* accelerometers */
static void test_orientation(struct udev *udev,
struct udev_device *dev,
const char *devpath)
{
OrientationUp old, new;
int fd, r;
struct input_event ev[64];
int got_syn = 0;
int got_x, got_y, got_z;
int x = 0, y = 0, z = 0;
char text[64];
old = get_prev_orientation(dev);
if ((fd = open(devpath, O_RDONLY)) < 0)
return;
got_x = got_y = got_z = 0;
while (1) {
int i;
r = read(fd, ev, sizeof(struct input_event) * 64);
if (r < (int) sizeof(struct input_event))
return;
for (i = 0; i < r / (int) sizeof(struct input_event); i++) {
if (got_syn == 1) {
if (ev[i].type == EV_ABS) {
SET_AXIS(x, ABS_X);
SET_AXIS(y, ABS_Y);
SET_AXIS(z, ABS_Z);
}
}
if (ev[i].type == EV_SYN && ev[i].code == SYN_REPORT) {
got_syn = 1;
}
if (got_x && got_y && got_z)
goto read_dev;
}
}
read_dev:
close(fd);
if (!got_x || !got_y || !got_z)
return;
new = orientation_calc(old, x, y, z);
snprintf(text, sizeof(text), "ID_INPUT_ACCELEROMETER_ORIENTATION=%s", orientation_to_string(new));
puts(text);
}
static void help(void)
{
printf("Usage: accelerometer [options] <device path>\n"
" --debug debug to stderr\n"
" --help print this help text\n\n");
}
int main (int argc, char** argv)
{
struct udev *udev;
struct udev_device *dev;
static const struct option options[] = {
{ "debug", no_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{}
};
char devpath[PATH_MAX];
char *devnode;
const char *id_path;
struct udev_enumerate *enumerate;
struct udev_list_entry *list_entry;
udev = udev_new();
if (udev == NULL)
return 1;
log_open();
udev_set_log_fn(udev, log_fn);
/* CLI argument parsing */
while (1) {
int option;
option = getopt_long(argc, argv, "dxh", options, NULL);
if (option == -1)
break;
switch (option) {
case 'd':
debug = 1;
log_set_max_level(LOG_DEBUG);
udev_set_log_priority(udev, LOG_DEBUG);
break;
case 'h':
help();
exit(0);
default:
exit(1);
}
}
if (argv[optind] == NULL) {
help();
exit(1);
}
/* get the device */
snprintf(devpath, sizeof(devpath), "/sys/%s", argv[optind]);
dev = udev_device_new_from_syspath(udev, devpath);
if (dev == NULL) {
fprintf(stderr, "unable to access '%s'\n", devpath);
return 1;
}
id_path = udev_device_get_property_value(dev, "ID_PATH");
if (id_path == NULL) {
fprintf (stderr, "unable to get property ID_PATH for '%s'", devpath);
return 0;
}
/* Get the children devices and find the devnode */
/* FIXME: use udev_enumerate_add_match_parent() instead */
devnode = NULL;
enumerate = udev_enumerate_new(udev);
udev_enumerate_add_match_property(enumerate, "ID_PATH", id_path);
udev_enumerate_add_match_subsystem(enumerate, "input");
udev_enumerate_scan_devices(enumerate);
udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
struct udev_device *device;
const char *node;
device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
udev_list_entry_get_name(list_entry));
if (device == NULL)
continue;
/* Already found it */
if (devnode != NULL) {
udev_device_unref(device);
continue;
}
node = udev_device_get_devnode(device);
if (node == NULL) {
udev_device_unref(device);
continue;
}
/* Use the event sub-device */
if (strstr(node, "/event") == NULL) {
udev_device_unref(device);
continue;
}
devnode = strdup(node);
udev_device_unref(device);
}
if (devnode == NULL) {
fprintf(stderr, "unable to get device node for '%s'\n", devpath);
return 0;
}
log_debug("opening accelerometer device %s\n", devnode);
test_orientation(udev, dev, devnode);
free(devnode);
log_close();
return 0;
}