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 static int debug = 0;
  73
  74 static void log_fn(struct udev *udev, int priority,
  75                    const char *file, int line, const char *fn,
  76                    const char *format, va_list args)
  77 {
  78         if (debug) {
  79                 fprintf(stderr, "%s: ", fn);
  80                 vfprintf(stderr, format, args);
  81         } else {
  82                 vsyslog(priority, format, args);
  83         }
  84 }
  85
  86 typedef enum {
  87         ORIENTATION_UNDEFINED,
  88         ORIENTATION_NORMAL,
  89         ORIENTATION_BOTTOM_UP,
  90         ORIENTATION_LEFT_UP,
  91         ORIENTATION_RIGHT_UP
  92 } OrientationUp;
  93
  94 static const char *orientations[] = {
  95         "undefined",
  96         "normal",
  97         "bottom-up",
  98         "left-up",
  99         "right-up",
 100         NULL
 101 };
 102
 103 #define ORIENTATION_UP_UP ORIENTATION_NORMAL
 104
 105 #define DEFAULT_THRESHOLD 250
 106 #define RADIANS_TO_DEGREES 180.0/M_PI
 107 #define SAME_AXIS_LIMIT 5
 108
 109 #define THRESHOLD_LANDSCAPE  25
 110 #define THRESHOLD_PORTRAIT  20
 111
 112 static const char *
 113 orientation_to_string (OrientationUp o)
 114 {
 115         return orientations[o];
 116 }
 117
 118 static OrientationUp
 119 string_to_orientation (const char *orientation)
 120 {
 121         int i;
 122
 123         if (orientation == NULL)
 124                 return ORIENTATION_UNDEFINED;
 125         for (i = 0; orientations[i] != NULL; i++) {
 126                 if (streq (orientation, orientations[i]))
 127                         return i;
 128         }
 129         return ORIENTATION_UNDEFINED;
 130 }
 131
 132 static OrientationUp
 133 orientation_calc (OrientationUp prev,
 134                   int x, int y, int z)
 135 {
 136         int rotation;
 137         OrientationUp ret = prev;
 138
 139         /* Portrait check */
 140         rotation = round(atan((double) x / sqrt(y * y + z * z)) * RADIANS_TO_DEGREES);
 141
 142         if (abs(rotation) > THRESHOLD_PORTRAIT) {
 143                 ret = (rotation < 0) ? ORIENTATION_LEFT_UP : ORIENTATION_RIGHT_UP;
 144
 145                 /* Some threshold to switching between portrait modes */
 146                 if (prev == ORIENTATION_LEFT_UP || prev == ORIENTATION_RIGHT_UP) {
 147                         if (abs(rotation) < SAME_AXIS_LIMIT) {
 148                                 ret = prev;
 149                         }
 150                 }
 151
 152         } else {
 153                 /* Landscape check */
 154                 rotation = round(atan((double) y / sqrt(x * x + z * z)) * RADIANS_TO_DEGREES);
 155
 156                 if (abs(rotation) > THRESHOLD_LANDSCAPE) {
 157                         ret = (rotation < 0) ? ORIENTATION_BOTTOM_UP : ORIENTATION_NORMAL;
 158
 159                         /* Some threshold to switching between landscape modes */
 160                         if (prev == ORIENTATION_BOTTOM_UP || prev == ORIENTATION_NORMAL) {
 161                                 if (abs(rotation) < SAME_AXIS_LIMIT) {
 162                                         ret = prev;
 163                                 }
 164                         }
 165                 }
 166         }
 167
 168         return ret;
 169 }
 170
 171 static OrientationUp
 172 get_prev_orientation(struct udev_device *dev)
 173 {
 174         const char *value;
 175
 176         value = udev_device_get_property_value(dev, "ID_INPUT_ACCELEROMETER_ORIENTATION");
 177         if (value == NULL)
 178                 return ORIENTATION_UNDEFINED;
 179         return string_to_orientation(value);
 180 }
 181
 182 #define SET_AXIS(axis, code_) if (ev[i].code == code_) { if (got_##axis == 0) { axis = ev[i].value; got_##axis = true; } }
 183
 184 /* accelerometers */
 185 static void test_orientation(struct udev *udev,
 186                              struct udev_device *dev,
 187                              const char *devpath)
 188 {
 189         OrientationUp old, new;
 190         _cleanup_close_ int fd = -1;
 191         struct input_event ev[64];
 192         bool got_syn = false;
 193         bool got_x = false, got_y = false, got_z = false;
 194         int x = 0, y = 0, z = 0;
 195         char text[64];
 196
 197         old = get_prev_orientation(dev);
 198
 199         fd = open(devpath, O_RDONLY);
 200         if (fd < 0)
 201                 return;
 202
 203         while (1) {
 204                 int i, r;
 205
 206                 r = read(fd, ev, sizeof(struct input_event) * 64);
 207
 208                 if (r < (int) sizeof(struct input_event))
 209                         return;
 210
 211                 for (i = 0; i < r / (int) sizeof(struct input_event); i++) {
 212                         if (got_syn) {
 213                                 if (ev[i].type == EV_ABS) {
 214                                         SET_AXIS(x, ABS_X);
 215                                         SET_AXIS(y, ABS_Y);
 216                                         SET_AXIS(z, ABS_Z);
 217                                 }
 218                         }
 219                         if (ev[i].type == EV_SYN && ev[i].code == SYN_REPORT)
 220                                 got_syn = true;
 221                         if (got_x && got_y && got_z)
 222                                 goto read_dev;
 223                 }
 224         }
 225
 226 read_dev:
 227         new = orientation_calc(old, x, y, z);
 228         snprintf(text, sizeof(text),
 229                  "ID_INPUT_ACCELEROMETER_ORIENTATION=%s", orientation_to_string(new));
 230         puts(text);
 231 }
 232
 233 static void help(void)
 234 {
 235         printf("Usage: accelerometer [options] <device path>\n"
 236                "  --debug         debug to stderr\n"
 237                "  --help          print this help text\n\n");
 238 }
 239
 240 int main (int argc, char** argv)
 241 {
 242         struct udev *udev;
 243         struct udev_device *dev;
 244
 245         static const struct option options[] = {
 246                 { "debug", no_argument, NULL, 'd' },
 247                 { "help", no_argument, NULL, 'h' },
 248                 {}
 249         };
 250
 251         char devpath[PATH_MAX];
 252         char *devnode;
 253         struct udev_enumerate *enumerate;
 254         struct udev_list_entry *list_entry;
 255
 256         udev = udev_new();
 257         if (udev == NULL)
 258                 return 1;
 259
 260         log_open();
 261         udev_set_log_fn(udev, log_fn);
 262
 263         /* CLI argument parsing */
 264         while (1) {
 265                 int option;
 266
 267                 option = getopt_long(argc, argv, "dxh", options, NULL);
 268                 if (option == -1)
 269                         break;
 270
 271                 switch (option) {
 272                 case 'd':
 273                         debug = 1;
 274                         log_set_max_level(LOG_DEBUG);
 275                         udev_set_log_priority(udev, LOG_DEBUG);
 276                         break;
 277                 case 'h':
 278                         help();
 279                         exit(0);
 280                 default:
 281                         exit(1);
 282                 }
 283         }
 284
 285         if (argv[optind] == NULL) {
 286                 help();
 287                 exit(1);
 288         }
 289
 290         /* get the device */
 291         snprintf(devpath, sizeof(devpath), "/sys/%s", argv[optind]);
 292         dev = udev_device_new_from_syspath(udev, devpath);
 293         if (dev == NULL) {
 294                 fprintf(stderr, "unable to access '%s'\n", devpath);
 295                 return 1;
 296         }
 297
 298         /* Get the children devices and find the devnode */
 299         devnode = NULL;
 300         enumerate = udev_enumerate_new(udev);
 301         udev_enumerate_add_match_parent(enumerate, dev);
 302         udev_enumerate_scan_devices(enumerate);
 303         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
 304                 struct udev_device *device;
 305                 const char *node;
 306
 307                 device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
 308                                                       udev_list_entry_get_name(list_entry));
 309                 if (device == NULL)
 310                         continue;
 311                 /* Already found it */
 312                 if (devnode != NULL) {
 313                         udev_device_unref(device);
 314                         continue;
 315                 }
 316
 317                 node = udev_device_get_devnode(device);
 318                 if (node == NULL) {
 319                         udev_device_unref(device);
 320                         continue;
 321                 }
 322                 /* Use the event sub-device */
 323                 if (strstr(node, "/event") == NULL) {
 324                         udev_device_unref(device);
 325                         continue;
 326                 }
 327
 328                 devnode = strdup(node);
 329                 udev_device_unref(device);
 330         }
 331
 332         if (devnode == NULL) {
 333                 fprintf(stderr, "unable to get device node for '%s'\n", devpath);
 334                 return 0;
 335         }
 336
 337         log_debug("opening accelerometer device %s\n", devnode);
 338         test_orientation(udev, dev, devnode);
 339         free(devnode);
 340         log_close();
 341         return 0;
 342 }