src/udev/accelerometer/accelerometer.c

   1 /*
   2  * accelerometer - exports device orientation through property
   3  *
   4  * When an "change" event is received on an accelerometer,
   5  * open its device node, and from the value, as well as the previous
   6  * value of the property, calculate the device's new orientation,
   7  * and export it as ID_INPUT_ACCELEROMETER_ORIENTATION.
   8  *
   9  * Possible values are:
  10  * undefined
  11  * * normal
  12  * * bottom-up
  13  * * left-up
  14  * * right-up
  15  *
  16  * The property will be persistent across sessions, and the new
  17  * orientations can be deducted from the previous one (it allows
  18  * for a threshold for switching between opposite ends of the
  19  * orientation).
  20  *
  21  * Copyright (C) 2011 Red Hat, Inc.
  22  * Author:
  23  *   Bastien Nocera <hadess@hadess.net>
  24  *
  25  * orientation_calc() from the sensorfw package
  26  * Copyright (C) 2009-2010 Nokia Corporation
  27  * Authors:
  28  *   Üstün Ergenoglu <ext-ustun.ergenoglu@nokia.com>
  29  *   Timo Rongas <ext-timo.2.rongas@nokia.com>
  30  *   Lihan Guo <lihan.guo@digia.com>
  31  *
  32  * This program is free software; you can redistribute it and/or modify
  33  * it under the terms of the GNU General Public License as published by
  34  * the Free Software Foundation; either version 2 of the License, or
  35  * (at your option) any later version.
  36  *
  37  * This program is distributed in the hope that it will be useful,
  38  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  39  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  40  * GNU General Public License for more details.
  41  *
  42  * You should have received a copy of the GNU General Public License along
  43  * with this program; if not, write to the Free Software Foundation, Inc.,
  44  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  45  */
  46
  47 #include <stdio.h>
  48 #include <string.h>
  49 #include <stdbool.h>
  50 #include <math.h>
  51 #include <sys/types.h>
  52 #include <sys/stat.h>
  53 #include <fcntl.h>
  54 #include <stdlib.h>
  55 #include <unistd.h>
  56 #include <getopt.h>
  57 #include <limits.h>
  58 #include <linux/limits.h>
  59 #include <linux/input.h>
  60
  61 #include "libudev.h"
  62 #include "libudev-private.h"
  63
  64 /* we must use this kernel-compatible implementation */
  65 #define BITS_PER_LONG (sizeof(unsigned long) * 8)
  66 #define NBITS(x) ((((x)-1)/BITS_PER_LONG)+1)
  67 #define OFF(x)  ((x)%BITS_PER_LONG)
  68 #define BIT(x)  (1UL<<OFF(x))
  69 #define LONG(x) ((x)/BITS_PER_LONG)
  70 #define test_bit(bit, array)    ((array[LONG(bit)] >> OFF(bit)) & 1)
  71
  72 typedef enum {
  73         ORIENTATION_UNDEFINED,
  74         ORIENTATION_NORMAL,
  75         ORIENTATION_BOTTOM_UP,
  76         ORIENTATION_LEFT_UP,
  77         ORIENTATION_RIGHT_UP
  78 } OrientationUp;
  79
  80 static const char *orientations[] = {
  81         "undefined",
  82         "normal",
  83         "bottom-up",
  84         "left-up",
  85         "right-up",
  86         NULL
  87 };
  88
  89 #define ORIENTATION_UP_UP ORIENTATION_NORMAL
  90
  91 #define DEFAULT_THRESHOLD 250
  92 #define RADIANS_TO_DEGREES 180.0/M_PI
  93 #define SAME_AXIS_LIMIT 5
  94
  95 #define THRESHOLD_LANDSCAPE  25
  96 #define THRESHOLD_PORTRAIT  20
  97
  98 static const char *
  99 orientation_to_string (OrientationUp o)
 100 {
 101         return orientations[o];
 102 }
 103
 104 static OrientationUp
 105 string_to_orientation (const char *orientation)
 106 {
 107         int i;
 108
 109         if (orientation == NULL)
 110                 return ORIENTATION_UNDEFINED;
 111         for (i = 0; orientations[i] != NULL; i++) {
 112                 if (streq (orientation, orientations[i]))
 113                         return i;
 114         }
 115         return ORIENTATION_UNDEFINED;
 116 }
 117
 118 static OrientationUp
 119 orientation_calc (OrientationUp prev,
 120                   int x, int y, int z)
 121 {
 122         int rotation;
 123         OrientationUp ret = prev;
 124
 125         /* Portrait check */
 126         rotation = round(atan((double) x / sqrt(y * y + z * z)) * RADIANS_TO_DEGREES);
 127
 128         if (abs(rotation) > THRESHOLD_PORTRAIT) {
 129                 ret = (rotation < 0) ? ORIENTATION_LEFT_UP : ORIENTATION_RIGHT_UP;
 130
 131                 /* Some threshold to switching between portrait modes */
 132                 if (prev == ORIENTATION_LEFT_UP || prev == ORIENTATION_RIGHT_UP) {
 133                         if (abs(rotation) < SAME_AXIS_LIMIT) {
 134                                 ret = prev;
 135                         }
 136                 }
 137
 138         } else {
 139                 /* Landscape check */
 140                 rotation = round(atan((double) y / sqrt(x * x + z * z)) * RADIANS_TO_DEGREES);
 141
 142                 if (abs(rotation) > THRESHOLD_LANDSCAPE) {
 143                         ret = (rotation < 0) ? ORIENTATION_BOTTOM_UP : ORIENTATION_NORMAL;
 144
 145                         /* Some threshold to switching between landscape modes */
 146                         if (prev == ORIENTATION_BOTTOM_UP || prev == ORIENTATION_NORMAL) {
 147                                 if (abs(rotation) < SAME_AXIS_LIMIT) {
 148                                         ret = prev;
 149                                 }
 150                         }
 151                 }
 152         }
 153
 154         return ret;
 155 }
 156
 157 static OrientationUp
 158 get_prev_orientation(struct udev_device *dev)
 159 {
 160         const char *value;
 161
 162         value = udev_device_get_property_value(dev, "ID_INPUT_ACCELEROMETER_ORIENTATION");
 163         if (value == NULL)
 164                 return ORIENTATION_UNDEFINED;
 165         return string_to_orientation(value);
 166 }
 167
 168 #define READ_AXIS(axis, var) { memzero(&abs_info, sizeof(abs_info)); r = ioctl(fd, EVIOCGABS(axis), &abs_info); if (r < 0) return; var = abs_info.value; }
 169
 170 /* accelerometers */
 171 static void test_orientation(struct udev *udev,
 172                              struct udev_device *dev,
 173                              const char *devpath)
 174 {
 175         OrientationUp old, new;
 176         _cleanup_close_ int fd = -1;
 177         struct input_absinfo abs_info;
 178         int x = 0, y = 0, z = 0;
 179         int r;
 180         char text[64];
 181
 182         old = get_prev_orientation(dev);
 183
 184         fd = open(devpath, O_RDONLY|O_CLOEXEC);
 185         if (fd < 0)
 186                 return;
 187
 188         READ_AXIS(ABS_X, x);
 189         READ_AXIS(ABS_Y, y);
 190         READ_AXIS(ABS_Z, z);
 191
 192         new = orientation_calc(old, x, y, z);
 193         snprintf(text, sizeof(text),
 194                  "ID_INPUT_ACCELEROMETER_ORIENTATION=%s", orientation_to_string(new));
 195         puts(text);
 196 }
 197
 198 static void help(void) {
 199
 200         printf("%s [options] <device path>\n\n"
 201                "Accelerometer device identification.\n\n"
 202                "  -h --help  Print this message\n"
 203                "  -d --debug Debug to stderr\n"
 204                , program_invocation_short_name);
 205 }
 206
 207 int main (int argc, char** argv)
 208 {
 209         struct udev *udev;
 210         struct udev_device *dev;
 211
 212         static const struct option options[] = {
 213                 { "debug", no_argument, NULL, 'd' },
 214                 { "help", no_argument, NULL, 'h' },
 215                 {}
 216         };
 217
 218         char devpath[PATH_MAX];
 219         char *devnode;
 220         struct udev_enumerate *enumerate;
 221         struct udev_list_entry *list_entry;
 222
 223         log_parse_environment();
 224         log_open();
 225
 226         udev = udev_new();
 227         if (udev == NULL)
 228                 return 1;
 229
 230         /* CLI argument parsing */
 231         while (1) {
 232                 int option;
 233
 234                 option = getopt_long(argc, argv, "dh", options, NULL);
 235                 if (option == -1)
 236                         break;
 237
 238                 switch (option) {
 239                 case 'd':
 240                         log_set_target(LOG_TARGET_CONSOLE);
 241                         log_set_max_level(LOG_DEBUG);
 242                         log_open();
 243                         break;
 244                 case 'h':
 245                         help();
 246                         exit(0);
 247                 default:
 248                         exit(1);
 249                 }
 250         }
 251
 252         if (argv[optind] == NULL) {
 253                 help();
 254                 exit(1);
 255         }
 256
 257         /* get the device */
 258         snprintf(devpath, sizeof(devpath), "/sys/%s", argv[optind]);
 259         dev = udev_device_new_from_syspath(udev, devpath);
 260         if (dev == NULL) {
 261                 fprintf(stderr, "unable to access '%s'\n", devpath);
 262                 return 1;
 263         }
 264
 265         /* Get the children devices and find the devnode */
 266         devnode = NULL;
 267         enumerate = udev_enumerate_new(udev);
 268         udev_enumerate_add_match_parent(enumerate, dev);
 269         udev_enumerate_scan_devices(enumerate);
 270         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
 271                 struct udev_device *device;
 272                 const char *node;
 273
 274                 device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
 275                                                       udev_list_entry_get_name(list_entry));
 276                 if (device == NULL)
 277                         continue;
 278                 /* Already found it */
 279                 if (devnode != NULL) {
 280                         udev_device_unref(device);
 281                         continue;
 282                 }
 283
 284                 node = udev_device_get_devnode(device);
 285                 if (node == NULL) {
 286                         udev_device_unref(device);
 287                         continue;
 288                 }
 289                 /* Use the event sub-device */
 290                 if (strstr(node, "/event") == NULL) {
 291                         udev_device_unref(device);
 292                         continue;
 293                 }
 294
 295                 devnode = strdup(node);
 296                 udev_device_unref(device);
 297         }
 298
 299         if (devnode == NULL) {
 300                 fprintf(stderr, "unable to get device node for '%s'\n", devpath);
 301                 return 0;
 302         }
 303
 304         log_debug("opening accelerometer device %s", devnode);
 305         test_orientation(udev, dev, devnode);
 306         free(devnode);
 307         log_close();
 308         return 0;
 309 }