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 _printf_(6,0)
  73 static void log_fn(struct udev *udev, int priority,
  74                    const char *file, int line, const char *fn,
  75                    const char *format, va_list args)
  76 {
  77         log_metav(priority, file, line, fn, format, args);
  78 }
  79
  80 typedef enum {
  81         ORIENTATION_UNDEFINED,
  82         ORIENTATION_NORMAL,
  83         ORIENTATION_BOTTOM_UP,
  84         ORIENTATION_LEFT_UP,
  85         ORIENTATION_RIGHT_UP
  86 } OrientationUp;
  87
  88 static const char *orientations[] = {
  89         "undefined",
  90         "normal",
  91         "bottom-up",
  92         "left-up",
  93         "right-up",
  94         NULL
  95 };
  96
  97 #define ORIENTATION_UP_UP ORIENTATION_NORMAL
  98
  99 #define DEFAULT_THRESHOLD 250
 100 #define RADIANS_TO_DEGREES 180.0/M_PI
 101 #define SAME_AXIS_LIMIT 5
 102
 103 #define THRESHOLD_LANDSCAPE  25
 104 #define THRESHOLD_PORTRAIT  20
 105
 106 static const char *
 107 orientation_to_string (OrientationUp o)
 108 {
 109         return orientations[o];
 110 }
 111
 112 static OrientationUp
 113 string_to_orientation (const char *orientation)
 114 {
 115         int i;
 116
 117         if (orientation == NULL)
 118                 return ORIENTATION_UNDEFINED;
 119         for (i = 0; orientations[i] != NULL; i++) {
 120                 if (streq (orientation, orientations[i]))
 121                         return i;
 122         }
 123         return ORIENTATION_UNDEFINED;
 124 }
 125
 126 static OrientationUp
 127 orientation_calc (OrientationUp prev,
 128                   int x, int y, int z)
 129 {
 130         int rotation;
 131         OrientationUp ret = prev;
 132
 133         /* Portrait check */
 134         rotation = round(atan((double) x / sqrt(y * y + z * z)) * RADIANS_TO_DEGREES);
 135
 136         if (abs(rotation) > THRESHOLD_PORTRAIT) {
 137                 ret = (rotation < 0) ? ORIENTATION_LEFT_UP : ORIENTATION_RIGHT_UP;
 138
 139                 /* Some threshold to switching between portrait modes */
 140                 if (prev == ORIENTATION_LEFT_UP || prev == ORIENTATION_RIGHT_UP) {
 141                         if (abs(rotation) < SAME_AXIS_LIMIT) {
 142                                 ret = prev;
 143                         }
 144                 }
 145
 146         } else {
 147                 /* Landscape check */
 148                 rotation = round(atan((double) y / sqrt(x * x + z * z)) * RADIANS_TO_DEGREES);
 149
 150                 if (abs(rotation) > THRESHOLD_LANDSCAPE) {
 151                         ret = (rotation < 0) ? ORIENTATION_BOTTOM_UP : ORIENTATION_NORMAL;
 152
 153                         /* Some threshold to switching between landscape modes */
 154                         if (prev == ORIENTATION_BOTTOM_UP || prev == ORIENTATION_NORMAL) {
 155                                 if (abs(rotation) < SAME_AXIS_LIMIT) {
 156                                         ret = prev;
 157                                 }
 158                         }
 159                 }
 160         }
 161
 162         return ret;
 163 }
 164
 165 static OrientationUp
 166 get_prev_orientation(struct udev_device *dev)
 167 {
 168         const char *value;
 169
 170         value = udev_device_get_property_value(dev, "ID_INPUT_ACCELEROMETER_ORIENTATION");
 171         if (value == NULL)
 172                 return ORIENTATION_UNDEFINED;
 173         return string_to_orientation(value);
 174 }
 175
 176 #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; }
 177
 178 /* accelerometers */
 179 static void test_orientation(struct udev *udev,
 180                              struct udev_device *dev,
 181                              const char *devpath)
 182 {
 183         OrientationUp old, new;
 184         _cleanup_close_ int fd = -1;
 185         struct input_absinfo abs_info;
 186         int x = 0, y = 0, z = 0;
 187         int r;
 188         char text[64];
 189
 190         old = get_prev_orientation(dev);
 191
 192         fd = open(devpath, O_RDONLY|O_CLOEXEC);
 193         if (fd < 0)
 194                 return;
 195
 196         READ_AXIS(ABS_X, x);
 197         READ_AXIS(ABS_Y, y);
 198         READ_AXIS(ABS_Z, z);
 199
 200         new = orientation_calc(old, x, y, z);
 201         snprintf(text, sizeof(text),
 202                  "ID_INPUT_ACCELEROMETER_ORIENTATION=%s", orientation_to_string(new));
 203         puts(text);
 204 }
 205
 206 static void help(void)
 207 {
 208         printf("Usage: accelerometer [options] <device path>\n"
 209                "  --debug         debug to stderr\n"
 210                "  --help          print this help text\n\n");
 211 }
 212
 213 int main (int argc, char** argv)
 214 {
 215         struct udev *udev;
 216         struct udev_device *dev;
 217
 218         static const struct option options[] = {
 219                 { "debug", no_argument, NULL, 'd' },
 220                 { "help", no_argument, NULL, 'h' },
 221                 {}
 222         };
 223
 224         char devpath[PATH_MAX];
 225         char *devnode;
 226         struct udev_enumerate *enumerate;
 227         struct udev_list_entry *list_entry;
 228
 229         log_parse_environment();
 230         log_open();
 231
 232         udev = udev_new();
 233         if (udev == NULL)
 234                 return 1;
 235
 236         udev_set_log_fn(udev, log_fn);
 237
 238         /* CLI argument parsing */
 239         while (1) {
 240                 int option;
 241
 242                 option = getopt_long(argc, argv, "dxh", options, NULL);
 243                 if (option == -1)
 244                         break;
 245
 246                 switch (option) {
 247                 case 'd':
 248                         log_set_target(LOG_TARGET_CONSOLE);
 249                         log_set_max_level(LOG_DEBUG);
 250                         udev_set_log_priority(udev, LOG_DEBUG);
 251                         log_open();
 252                         break;
 253                 case 'h':
 254                         help();
 255                         exit(0);
 256                 default:
 257                         exit(1);
 258                 }
 259         }
 260
 261         if (argv[optind] == NULL) {
 262                 help();
 263                 exit(1);
 264         }
 265
 266         /* get the device */
 267         snprintf(devpath, sizeof(devpath), "/sys/%s", argv[optind]);
 268         dev = udev_device_new_from_syspath(udev, devpath);
 269         if (dev == NULL) {
 270                 fprintf(stderr, "unable to access '%s'\n", devpath);
 271                 return 1;
 272         }
 273
 274         /* Get the children devices and find the devnode */
 275         devnode = NULL;
 276         enumerate = udev_enumerate_new(udev);
 277         udev_enumerate_add_match_parent(enumerate, dev);
 278         udev_enumerate_scan_devices(enumerate);
 279         udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
 280                 struct udev_device *device;
 281                 const char *node;
 282
 283                 device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
 284                                                       udev_list_entry_get_name(list_entry));
 285                 if (device == NULL)
 286                         continue;
 287                 /* Already found it */
 288                 if (devnode != NULL) {
 289                         udev_device_unref(device);
 290                         continue;
 291                 }
 292
 293                 node = udev_device_get_devnode(device);
 294                 if (node == NULL) {
 295                         udev_device_unref(device);
 296                         continue;
 297                 }
 298                 /* Use the event sub-device */
 299                 if (strstr(node, "/event") == NULL) {
 300                         udev_device_unref(device);
 301                         continue;
 302                 }
 303
 304                 devnode = strdup(node);
 305                 udev_device_unref(device);
 306         }
 307
 308         if (devnode == NULL) {
 309                 fprintf(stderr, "unable to get device node for '%s'\n", devpath);
 310                 return 0;
 311         }
 312
 313         log_debug("opening accelerometer device %s", devnode);
 314         test_orientation(udev, dev, devnode);
 315         free(devnode);
 316         log_close();
 317         return 0;
 318 }