2 * Copyright (C) 2014 Intel Corporation.
11 #include <sys/epoll.h>
12 #include <sys/socket.h>
13 #include <utils/Log.h>
14 #include <hardware/sensors.h>
16 #include "enumeration.h"
18 #include "transform.h"
19 #include "calibration.h"
20 #include "description.h"
21 #include "filtering.h"
23 /* Currently active sensors count, per device */
24 static int poll_sensors_per_dev[MAX_DEVICES]; /* poll-mode sensors */
25 static int trig_sensors_per_dev[MAX_DEVICES]; /* trigger, event based */
27 static int device_fd[MAX_DEVICES]; /* fd on the /dev/iio:deviceX file */
28 static int has_iio_ts[MAX_DEVICES]; /* ts channel available on this iio dev */
29 static int expected_dev_report_size[MAX_DEVICES]; /* expected iio scan len */
30 static int poll_fd; /* epoll instance covering all enabled sensors */
32 static int active_poll_sensors; /* Number of enabled poll-mode sensors */
34 /* We use pthread condition variables to get worker threads out of sleep */
35 static pthread_condattr_t thread_cond_attr [MAX_SENSORS];
36 static pthread_cond_t thread_release_cond [MAX_SENSORS];
37 static pthread_mutex_t thread_release_mutex [MAX_SENSORS];
40 * We associate tags to each of our poll set entries. These tags have the following values:
41 * - a iio device number if the fd is a iio character device fd
42 * - THREAD_REPORT_TAG_BASE + sensor handle if the fd is the receiving end of a pipe used by a sysfs data acquisition thread
44 #define THREAD_REPORT_TAG_BASE 1000
46 /* If buffer enable fails, we may want to retry a few times before giving up */
47 #define ENABLE_BUFFER_RETRIES 3
48 #define ENABLE_BUFFER_RETRY_DELAY_MS 10
51 inline int is_enabled (int s)
53 return sensor[s].directly_enabled || sensor[s].ref_count;
57 static int check_state_change (int s, int enabled, int from_virtual)
60 if (sensor[s].directly_enabled)
61 return 0; /* We're being enabled but already were directly activated: no change. */
64 sensor[s].directly_enabled = 1; /* We're being directly enabled */
66 if (sensor[s].ref_count)
67 return 0; /* We were already indirectly enabled */
69 return 1; /* Do continue enabling this sensor */
73 return 0; /* We are being disabled but already were: no change */
75 if (from_virtual && sensor[s].directly_enabled)
76 return 0; /* We're indirectly disabled but the base is still active */
78 sensor[s].directly_enabled = 0; /* We're now directly disabled */
80 if (!from_virtual && sensor[s].ref_count)
81 return 0; /* We still have ref counts */
83 return 1; /* Do continue disabling this sensor */
87 static int enable_buffer (int dev_num, int enabled)
89 char sysfs_path[PATH_MAX];
90 int retries = ENABLE_BUFFER_RETRIES;
92 sprintf(sysfs_path, ENABLE_PATH, dev_num);
95 /* Low level, non-multiplexed, enable/disable routine */
96 if (sysfs_write_int(sysfs_path, enabled) > 0)
99 ALOGE("Failed enabling buffer on dev%d, retrying", dev_num);
100 usleep(ENABLE_BUFFER_RETRY_DELAY_MS*1000);
104 ALOGE("Could not enable buffer\n");
109 static int setup_trigger (int s, const char* trigger_val)
111 char sysfs_path[PATH_MAX];
112 int ret = -1, attempts = 5;
114 sprintf(sysfs_path, TRIGGER_PATH, sensor[s].dev_num);
116 if (trigger_val[0] != '\n')
117 ALOGI("Setting S%d (%s) trigger to %s\n", s, sensor[s].friendly_name, trigger_val);
119 while (ret == -1 && attempts) {
120 ret = sysfs_write_str(sysfs_path, trigger_val);
125 sensor[s].selected_trigger = trigger_val;
127 ALOGE("Setting S%d (%s) trigger to %s FAILED.\n", s, sensor[s].friendly_name, trigger_val);
132 static void enable_iio_timestamp (int dev_num, int known_channels)
134 /* Check if we have a dedicated iio timestamp channel */
136 char spec_buf[MAX_TYPE_SPEC_LEN];
137 char sysfs_path[PATH_MAX];
140 sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_type");
142 n = sysfs_read_str(sysfs_path, spec_buf, sizeof(spec_buf));
147 if (strcmp(spec_buf, "le:s64/64>>0"))
150 /* OK, type is int64_t as expected, in little endian representation */
152 sprintf(sysfs_path, CHANNEL_PATH"%s", dev_num, "in_timestamp_index");
154 if (sysfs_read_int(sysfs_path, &n))
157 /* Check that the timestamp comes after the other fields we read */
158 if (n != known_channels)
161 /* Try enabling that channel */
162 sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_en");
164 sysfs_write_int(sysfs_path, 1);
166 if (sysfs_read_int(sysfs_path, &n))
170 ALOGI("Detected timestamp channel on iio device %d\n", dev_num);
171 has_iio_ts[dev_num] = 1;
176 static int decode_type_spec (const char type_buf[MAX_TYPE_SPEC_LEN], datum_info_t *type_info)
178 /* Return size in bytes for this type specification, or -1 in error */
181 unsigned int realbits, storagebits, shift;
184 /* Valid specs: "le:u10/16>>0", "le:s16/32>>0" or "le:s32/32>>0" */
186 tokens = sscanf(type_buf, "%ce:%c%u/%u>>%u", &endianness, &sign, &realbits, &storagebits, &shift);
188 if (tokens != 5 || (endianness != 'b' && endianness != 'l') || (sign != 'u' && sign != 's') ||
189 realbits > storagebits || (storagebits != 16 && storagebits != 32 && storagebits != 64)) {
190 ALOGE("Invalid iio channel type spec: %s\n", type_buf);
194 type_info->endianness = endianness;
195 type_info->sign = sign;
196 type_info->realbits = (short) realbits;
197 type_info->storagebits = (short) storagebits;
198 type_info->shift = (short) shift;
200 return storagebits / 8;
204 void build_sensor_report_maps (int dev_num)
207 * Read sysfs files from a iio device's scan_element directory, and build a couple of tables from that data. These tables will tell, for
208 * each sensor, where to gather relevant data in a device report, i.e. the structure that we read from the /dev/iio:deviceX file in order to
209 * sensor report, itself being the data that we return to Android when a sensor poll completes. The mapping should be straightforward in the
210 * case where we have a single sensor active per iio device but, this is not the general case. In general several sensors can be handled
211 * through a single iio device, and the _en, _index and _type syfs entries all concur to paint a picture of what the structure of the
221 char spec_buf[MAX_TYPE_SPEC_LEN];
222 datum_info_t* ch_info;
224 char sysfs_path[PATH_MAX];
227 int channel_size_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
228 int sensor_handle_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
229 int channel_number_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
233 /* For each sensor that is linked to this device */
234 for (s=0; s<sensor_count; s++) {
235 if (sensor[s].dev_num != dev_num)
238 i = sensor[s].catalog_index;
240 /* Read channel details through sysfs attributes */
241 for (c=0; c<sensor[s].num_channels; c++) {
243 /* Read _type file */
244 sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].type_path);
246 n = sysfs_read_str(sysfs_path, spec_buf, sizeof(spec_buf));
249 ALOGW( "Failed to read type: %s\n", sysfs_path);
253 ch_spec = sensor[s].channel[c].type_spec;
255 memcpy(ch_spec, spec_buf, sizeof(spec_buf));
257 ch_info = &sensor[s].channel[c].type_info;
259 size = decode_type_spec(ch_spec, ch_info);
261 /* Read _index file */
262 sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].index_path);
264 n = sysfs_read_int(sysfs_path, &ch_index);
267 ALOGW( "Failed to read index: %s\n", sysfs_path);
271 if (ch_index >= MAX_SENSORS) {
272 ALOGE("Index out of bounds!: %s\n", sysfs_path);
276 /* Record what this index is about */
278 sensor_handle_from_index [ch_index] = s;
279 channel_number_from_index[ch_index] = c;
280 channel_size_from_index [ch_index] = size;
285 /* Stop sampling - if we are recovering from hal restart */
286 enable_buffer(dev_num, 0);
287 setup_trigger(s, "\n");
289 /* Turn on channels we're aware of */
290 for (c=0;c<sensor[s].num_channels; c++) {
291 sprintf(sysfs_path, CHANNEL_PATH "%s", sensor[s].dev_num, sensor_catalog[i].channel[c].en_path);
292 sysfs_write_int(sysfs_path, 1);
296 ALOGI("Found %d channels on iio device %d\n", known_channels, dev_num);
299 * Now that we know which channels are defined, their sizes and their ordering, update channels offsets within device report. Note: there
300 * is a possibility that several sensors share the same index, with their data fields being isolated by masking and shifting as specified
301 * through the real bits and shift values in type attributes. This case is not currently supported. Also, the code below assumes no hole in
302 * the sequence of indices, so it is dependent on discovery of all sensors.
306 for (i=0; i<MAX_SENSORS * MAX_CHANNELS; i++) {
307 s = sensor_handle_from_index[i];
308 c = channel_number_from_index[i];
309 size = channel_size_from_index[i];
314 ALOGI("S%d C%d : offset %d, size %d, type %s\n", s, c, offset, size, sensor[s].channel[c].type_spec);
316 sensor[s].channel[c].offset = offset;
317 sensor[s].channel[c].size = size;
322 /* Enable the timestamp channel if there is one available */
323 enable_iio_timestamp(dev_num, known_channels);
325 /* Add padding and timestamp size if it's enabled on this iio device */
326 if (has_iio_ts[dev_num])
327 offset = (offset+7)/8*8 + sizeof(int64_t);
329 expected_dev_report_size[dev_num] = offset;
330 ALOGI("Expecting %d scan length on iio dev %d\n", offset, dev_num);
332 if (expected_dev_report_size[dev_num] > MAX_DEVICE_REPORT_SIZE) {
333 ALOGE("Unexpectedly large scan buffer on iio dev%d: %d bytes\n", dev_num, expected_dev_report_size[dev_num]);
335 expected_dev_report_size[dev_num] = MAX_DEVICE_REPORT_SIZE;
340 int adjust_counters (int s, int enabled, int from_virtual)
343 * Adjust counters based on sensor enable action. Return values are:
344 * 0 if the operation was completed and we're all set
345 * 1 if we toggled the state of the sensor and there's work left
348 int dev_num = sensor[s].dev_num;
350 if (!check_state_change(s, enabled, from_virtual))
351 return 0; /* The state of the sensor remains the same: we're done */
354 ALOGI("Enabling sensor %d (iio device %d: %s)\n", s, dev_num, sensor[s].friendly_name);
356 switch (sensor[s].type) {
357 case SENSOR_TYPE_MAGNETIC_FIELD:
358 compass_read_data(&sensor[s]);
361 case SENSOR_TYPE_GYROSCOPE:
362 gyro_cal_init(&sensor[s]);
366 ALOGI("Disabling sensor %d (iio device %d: %s)\n", s, dev_num, sensor[s].friendly_name);
368 /* Sensor disabled, lower report available flag */
369 sensor[s].report_pending = 0;
371 if (sensor[s].type == SENSOR_TYPE_MAGNETIC_FIELD)
372 compass_store_data(&sensor[s]);
374 if (sensor[s].type == SENSOR_TYPE_GYROSCOPE)
375 gyro_store_data(&sensor[s]);
378 /* We changed the state of a sensor: adjust device ref counts */
380 if (!sensor[s].is_polling) {
383 trig_sensors_per_dev[dev_num]++;
385 trig_sensors_per_dev[dev_num]--;
391 active_poll_sensors++;
392 poll_sensors_per_dev[dev_num]++;
396 active_poll_sensors--;
397 poll_sensors_per_dev[dev_num]--;
402 static int get_field_count (int s)
404 switch (sensor[s].type) {
405 case SENSOR_TYPE_ACCELEROMETER: /* m/s^2 */
406 case SENSOR_TYPE_MAGNETIC_FIELD: /* micro-tesla */
407 case SENSOR_TYPE_ORIENTATION: /* degrees */
408 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
409 case SENSOR_TYPE_GYROSCOPE: /* radians/s */
412 case SENSOR_TYPE_LIGHT: /* SI lux units */
413 case SENSOR_TYPE_AMBIENT_TEMPERATURE: /* °C */
414 case SENSOR_TYPE_TEMPERATURE: /* °C */
415 case SENSOR_TYPE_PROXIMITY: /* centimeters */
416 case SENSOR_TYPE_PRESSURE: /* hecto-pascal */
417 case SENSOR_TYPE_RELATIVE_HUMIDITY: /* percent */
420 case SENSOR_TYPE_ROTATION_VECTOR:
424 ALOGE("Unknown sensor type!\n");
425 return 0; /* Drop sample */
430 * CTS acceptable thresholds:
431 * EventGapVerification.java: (th <= 1.8)
432 * FrequencyVerification.java: (0.9)*(expected freq) => (th <= 1.1111)
434 #define THRESHOLD 1.10
435 #define MAX_DELAY 500000000 /* 500 ms */
437 void set_report_ts(int s, int64_t ts)
439 int64_t maxTs, period;
442 * A bit of a hack to please a bunch of cts tests. They
443 * expect the timestamp to be exacly according to the set-up
444 * frequency but if we're simply getting the timestamp at hal level
445 * this may not be the case. Perhaps we'll get rid of this when
446 * we'll be reading the timestamp from the iio channel for all sensors
448 if (sensor[s].report_ts && sensor[s].sampling_rate &&
449 REPORTING_MODE(sensor_desc[s].flags) == SENSOR_FLAG_CONTINUOUS_MODE)
451 period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
452 maxTs = sensor[s].report_ts + THRESHOLD * period;
453 /* If we're too far behind get back on track */
454 if (ts - maxTs >= MAX_DELAY)
456 sensor[s].report_ts = (ts < maxTs ? ts : maxTs);
458 sensor[s].report_ts = ts;
462 static void* acquisition_routine (void* param)
465 * Data acquisition routine run in a dedicated thread, covering a single sensor. This loop will periodically retrieve sampling data through
466 * sysfs, then package it as a sample and transfer it to our master poll loop through a report fd. Checks for a cancellation signal quite
467 * frequently, as the thread may be disposed of at any time. Note that Bionic does not provide pthread_cancel / pthread_testcancel...
470 int s = (int) (size_t) param;
472 sensors_event_t data = {0};
475 struct timespec target_time;
476 int64_t timestamp, period, start, stop;
478 if (s < 0 || s >= sensor_count) {
479 ALOGE("Invalid sensor handle!\n");
483 ALOGI("Entering S%d (%s) data acquisition thread: rate:%g\n", s, sensor[s].friendly_name, sensor[s].sampling_rate);
485 if (sensor[s].sampling_rate <= 0) {
486 ALOGE("Invalid rate in acquisition routine for sensor %d: %g\n", s, sensor[s].sampling_rate);
490 /* Initialize data fields that will be shared by all sensor reports */
491 data.version = sizeof(sensors_event_t);
493 data.type = sensor[s].type;
495 num_fields = get_field_count(s);
498 * Each condition variable is associated to a mutex that has to be locked by the thread that's waiting on it. We use these condition
499 * variables to get the acquisition threads out of sleep quickly after the sampling rate is adjusted, or the sensor is disabled.
501 pthread_mutex_lock(&thread_release_mutex[s]);
503 /* Pinpoint the moment we start sampling */
504 timestamp = get_timestamp_monotonic();
506 /* Check and honor termination requests */
507 while (sensor[s].thread_data_fd[1] != -1) {
508 start = get_timestamp_boot();
510 /* Read values through sysfs */
511 for (c=0; c<num_fields; c++) {
512 data.data[c] = acquire_immediate_value(s, c);
514 /* Check and honor termination requests */
515 if (sensor[s].thread_data_fd[1] == -1)
518 stop = get_timestamp_boot();
519 set_report_ts(s, start/2 + stop/2);
520 data.timestamp = sensor[s].report_ts;
521 /* If the sample looks good */
522 if (sensor[s].ops.finalize(s, &data)) {
524 /* Pipe it for transmission to poll loop */
525 ret = write(sensor[s].thread_data_fd[1], &data, sizeof(sensors_event_t));
527 if (ret != sizeof(sensors_event_t))
528 ALOGE("S%d write failure: wrote %d, got %d\n", s, sizeof(sensors_event_t), ret);
531 /* Check and honor termination requests */
532 if (sensor[s].thread_data_fd[1] == -1)
535 /* Recalculate period assuming sensor[s].sampling_rate can be changed dynamically during the thread run */
536 if (sensor[s].sampling_rate <= 0) {
537 ALOGE("Unexpected sampling rate for sensor %d: %g\n", s, sensor[s].sampling_rate);
541 period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
543 set_timestamp(&target_time, timestamp);
545 /* Wait until the sampling time elapses, or a rate change is signaled, or a thread exit is requested */
546 ret = pthread_cond_timedwait(&thread_release_cond[s], &thread_release_mutex[s], &target_time);
550 ALOGV("Acquisition thread for S%d exiting\n", s);
551 pthread_mutex_unlock(&thread_release_mutex[s]);
557 static void start_acquisition_thread (int s)
559 int incoming_data_fd;
562 struct epoll_event ev = {0};
564 ALOGV("Initializing acquisition context for sensor %d\n", s);
566 /* Create condition variable and mutex for quick thread release */
567 ret = pthread_condattr_init(&thread_cond_attr[s]);
568 ret = pthread_condattr_setclock(&thread_cond_attr[s], CLOCK_MONOTONIC);
569 ret = pthread_cond_init(&thread_release_cond[s], &thread_cond_attr[s]);
570 ret = pthread_mutex_init(&thread_release_mutex[s], NULL);
572 /* Create a pipe for inter thread communication */
573 ret = pipe(sensor[s].thread_data_fd);
575 incoming_data_fd = sensor[s].thread_data_fd[0];
578 ev.data.u32 = THREAD_REPORT_TAG_BASE + s;
580 /* Add incoming side of pipe to our poll set, with a suitable tag */
581 ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, incoming_data_fd , &ev);
583 ALOGE("Failed adding %d to poll set (%s)\n",
584 incoming_data_fd, strerror(errno));
587 /* Create and start worker thread */
588 ret = pthread_create(&sensor[s].acquisition_thread, NULL, acquisition_routine, (void*) (size_t) s);
592 static void stop_acquisition_thread (int s)
594 int incoming_data_fd = sensor[s].thread_data_fd[0];
595 int outgoing_data_fd = sensor[s].thread_data_fd[1];
597 ALOGV("Tearing down acquisition context for sensor %d\n", s);
599 /* Delete the incoming side of the pipe from our poll set */
600 epoll_ctl(poll_fd, EPOLL_CTL_DEL, incoming_data_fd, NULL);
602 /* Mark the pipe ends as invalid ; that's a cheap exit flag */
603 sensor[s].thread_data_fd[0] = -1;
604 sensor[s].thread_data_fd[1] = -1;
606 /* Close both sides of our pipe */
607 close(incoming_data_fd);
608 close(outgoing_data_fd);
610 /* Stop acquisition thread and clean up thread handle */
611 pthread_cond_signal(&thread_release_cond[s]);
612 pthread_join(sensor[s].acquisition_thread, NULL);
614 /* Clean up our sensor descriptor */
615 sensor[s].acquisition_thread = -1;
617 /* Delete condition variable and mutex */
618 pthread_cond_destroy(&thread_release_cond[s]);
619 pthread_mutex_destroy(&thread_release_mutex[s]);
623 static int is_fast_accelerometer (int s)
626 * Some games don't react well to accelerometers using any-motion triggers. Even very low thresholds seem to trip them, and they tend to
627 * request fairly high event rates. Favor continuous triggers if the sensor is an accelerometer and uses a sampling rate of at least 25.
630 if (sensor[s].type != SENSOR_TYPE_ACCELEROMETER)
633 if (sensor[s].sampling_rate < 25)
640 static void tentative_switch_trigger (int s)
643 * Under certain situations it may be beneficial to use an alternate trigger:
645 * - for applications using the accelerometer with high sampling rates, prefer the continuous trigger over the any-motion one, to avoid
646 * jumps related to motion thresholds
649 if (is_fast_accelerometer(s) && !(sensor[s].quirks & QUIRK_TERSE_DRIVER) && sensor[s].selected_trigger == sensor[s].motion_trigger_name)
650 setup_trigger(s, sensor[s].init_trigger_name);
654 static float get_group_max_sampling_rate (int s)
656 /* Review the sampling rates of linked sensors and return the maximum */
660 float arbitrated_rate = 0;
663 arbitrated_rate = sensor[s].requested_rate;
665 /* If any of the currently active sensors built on top of this one need a higher sampling rate, switch to this rate */
666 for (i = 0; i < sensor_count; i++)
667 for (vi = 0; vi < sensor[i].base_count; vi++)
668 if (sensor[i].base[vi] == s && is_enabled(i) && sensor[i].requested_rate > arbitrated_rate) /* If sensor i depends on sensor s */
669 arbitrated_rate = sensor[i].requested_rate;
671 /* If any of the currently active sensors we rely on is using a higher sampling rate, switch to this rate */
672 for (vi = 0; vi < sensor[s].base_count; vi++) {
673 i = sensor[s].base[vi];
674 if (is_enabled(i) && sensor[i].requested_rate > arbitrated_rate)
675 arbitrated_rate = sensor[i].requested_rate;
678 return arbitrated_rate;
682 static int sensor_set_rate (int s, float requested_rate)
684 /* Set the rate at which a specific sensor should report events. See Android sensors.h for indication on sensor trigger modes */
686 char sysfs_path[PATH_MAX];
687 char avail_sysfs_path[PATH_MAX];
688 int dev_num = sensor[s].dev_num;
689 int i = sensor[s].catalog_index;
690 const char *prefix = sensor_catalog[i].tag;
691 int per_sensor_sampling_rate;
692 int per_device_sampling_rate;
697 float group_max_sampling_rate;
698 float cur_sampling_rate; /* Currently used sampling rate */
699 float arb_sampling_rate; /* Granted sampling rate after arbitration */
701 ALOGV("Sampling rate %g requested on sensor %d (%s)\n", requested_rate, s, sensor[s].friendly_name);
703 sensor[s].requested_rate = requested_rate;
705 arb_sampling_rate = requested_rate;
707 if (arb_sampling_rate < sensor[s].min_supported_rate) {
708 ALOGV("Sampling rate %g too low for %s, using %g instead\n", arb_sampling_rate, sensor[s].friendly_name, sensor[s].min_supported_rate);
709 arb_sampling_rate = sensor[s].min_supported_rate;
712 /* If one of the linked sensors uses a higher rate, adopt it */
713 group_max_sampling_rate = get_group_max_sampling_rate(s);
715 if (arb_sampling_rate < group_max_sampling_rate) {
716 ALOGV("Using %s sampling rate to %g too due to dependency\n", sensor[s].friendly_name, arb_sampling_rate);
717 arb_sampling_rate = group_max_sampling_rate;
720 if (sensor[s].max_supported_rate && arb_sampling_rate > sensor[s].max_supported_rate) {
721 ALOGV("Sampling rate %g too high for %s, using %g instead\n", arb_sampling_rate, sensor[s].friendly_name, sensor[s].max_supported_rate);
722 arb_sampling_rate = sensor[s].max_supported_rate;
725 sensor[s].sampling_rate = arb_sampling_rate;
727 /* If the sensor is virtual, we're done */
728 if (sensor[s].is_virtual)
731 /* If we're dealing with a poll-mode sensor */
732 if (sensor[s].is_polling) {
734 pthread_cond_signal(&thread_release_cond[s]); /* Wake up thread so the new sampling rate gets used */
738 sprintf(sysfs_path, SENSOR_SAMPLING_PATH, dev_num, prefix);
740 if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1) {
741 per_sensor_sampling_rate = 1;
742 per_device_sampling_rate = 0;
744 per_sensor_sampling_rate = 0;
746 sprintf(sysfs_path, DEVICE_SAMPLING_PATH, dev_num);
748 if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1)
749 per_device_sampling_rate = 1;
751 per_device_sampling_rate = 0;
754 if (!per_sensor_sampling_rate && !per_device_sampling_rate) {
755 ALOGE("No way to adjust sampling rate on sensor %d\n", s);
759 /* Check if we have contraints on allowed sampling rates */
761 sprintf(avail_sysfs_path, DEVICE_AVAIL_FREQ_PATH, dev_num);
763 if (sysfs_read_str(avail_sysfs_path, freqs_buf, sizeof(freqs_buf)) > 0) {
766 /* Decode allowed sampling rates string, ex: "10 20 50 100" */
768 /* While we're not at the end of the string */
769 while (*cursor && cursor[0]) {
771 /* Decode a single value */
772 sr = strtod(cursor, NULL);
774 /* If this matches the selected rate, we're happy. Have some tolerance for rounding errors and avoid needless jumps to higher rates */
775 if (fabs(arb_sampling_rate - sr) <= 0.001) {
776 arb_sampling_rate = sr;
781 * If we reached a higher value than the desired rate, adjust selected rate so it matches the first higher available one and
782 * stop parsing - this makes the assumption that rates are sorted by increasing value in the allowed frequencies string.
784 if (sr > arb_sampling_rate) {
785 arb_sampling_rate = sr;
790 while (cursor[0] && !isspace(cursor[0]))
794 while (cursor[0] && isspace(cursor[0]))
799 if (sensor[s].max_supported_rate &&
800 arb_sampling_rate > sensor[s].max_supported_rate) {
801 arb_sampling_rate = sensor[s].max_supported_rate;
804 /* Coordinate with others active sensors on the same device, if any */
805 if (per_device_sampling_rate)
806 for (n=0; n<sensor_count; n++)
807 if (n != s && sensor[n].dev_num == dev_num && sensor[n].num_channels && is_enabled(n) && sensor[n].sampling_rate > arb_sampling_rate) {
808 ALOGV("Sampling rate shared between %s and %s, using %g instead of %g\n", sensor[s].friendly_name, sensor[n].friendly_name,
809 sensor[n].sampling_rate, arb_sampling_rate);
810 arb_sampling_rate = sensor[n].sampling_rate;
813 sensor[s].sampling_rate = arb_sampling_rate;
815 /* Update actual sampling rate field for this sensor and others which may be sharing the same sampling rate */
816 if (per_device_sampling_rate)
817 for (n=0; n<sensor_count; n++)
818 if (sensor[n].dev_num == dev_num && n != s && sensor[n].num_channels)
819 sensor[n].sampling_rate = arb_sampling_rate;
821 /* If the desired rate is already active we're all set */
822 if (arb_sampling_rate == cur_sampling_rate)
825 ALOGI("Sensor %d (%s) sampling rate set to %g\n", s, sensor[s].friendly_name, arb_sampling_rate);
827 if (trig_sensors_per_dev[dev_num])
828 enable_buffer(dev_num, 0);
830 sysfs_write_float(sysfs_path, arb_sampling_rate);
832 /* Check if it makes sense to use an alternate trigger */
833 tentative_switch_trigger(s);
835 if (trig_sensors_per_dev[dev_num])
836 enable_buffer(dev_num, 1);
842 static void reapply_sampling_rates (int s)
845 * The specified sensor was either enabled or disabled. Other sensors in the same group may have constraints related to this sensor
846 * sampling rate on their own sampling rate, so reevaluate them by retrying to use their requested sampling rate, rather than the one
847 * that ended up being used after arbitration.
852 if (sensor[s].is_virtual) {
853 /* Take care of downwards dependencies */
854 for (i=0; i<sensor[s].base_count; i++) {
855 base = sensor[s].base[i];
856 sensor_set_rate(base, sensor[base].requested_rate);
862 for (i=0; i<sensor_count; i++)
863 for (j=0; j<sensor[i].base_count; j++)
864 if (sensor[i].base[j] == s) /* If sensor i depends on sensor s */
865 sensor_set_rate(i, sensor[i].requested_rate);
869 static int sensor_activate_virtual (int s, int enabled, int from_virtual)
873 sensor[s].event_count = 0;
874 sensor[s].meta_data_pending = 0;
876 if (!check_state_change(s, enabled, from_virtual))
877 return 0; /* The state of the sensor remains the same ; we're done */
880 ALOGI("Enabling sensor %d (%s)\n", s, sensor[s].friendly_name);
882 ALOGI("Disabling sensor %d (%s)\n", s, sensor[s].friendly_name);
884 sensor[s].report_pending = 0;
886 for (i=0; i<sensor[s].base_count; i++) {
888 base = sensor[s].base[i];
889 sensor_activate(base, enabled, 1);
892 sensor[base].ref_count++;
894 sensor[base].ref_count--;
897 /* Reevaluate sampling rates of linked sensors */
898 reapply_sampling_rates(s);
903 int sensor_activate (int s, int enabled, int from_virtual)
905 char device_name[PATH_MAX];
906 struct epoll_event ev = {0};
909 int dev_num = sensor[s].dev_num;
911 if (sensor[s].is_virtual)
912 return sensor_activate_virtual(s, enabled, from_virtual);
914 /* Prepare the report timestamp field for the first event, see set_report_ts method */
915 sensor[s].report_ts = 0;
917 ret = adjust_counters(s, enabled, from_virtual);
919 /* If the operation was neutral in terms of state, we're done */
923 sensor[s].event_count = 0;
924 sensor[s].meta_data_pending = 0;
927 setup_noise_filtering(s); /* Initialize filtering data if required */
929 if (!sensor[s].is_polling) {
932 enable_buffer(dev_num, 0);
933 setup_trigger(s, "\n");
935 /* If there's at least one sensor enabled on this iio device */
936 if (trig_sensors_per_dev[dev_num]) {
939 setup_trigger(s, sensor[s].init_trigger_name);
940 enable_buffer(dev_num, 1);
945 * Make sure we have a fd on the character device ; conversely, close the fd if no one is using associated sensors anymore. The assumption
946 * here is that the underlying driver will power on the relevant hardware block while someone holds a fd on the device.
948 dev_fd = device_fd[dev_num];
951 if (sensor[s].is_polling)
952 stop_acquisition_thread(s);
954 if (dev_fd != -1 && !poll_sensors_per_dev[dev_num] && !trig_sensors_per_dev[dev_num]) {
955 /* Stop watching this fd. This should be a no-op in case this fd was not in the poll set. */
956 epoll_ctl(poll_fd, EPOLL_CTL_DEL, dev_fd, NULL);
959 device_fd[dev_num] = -1;
962 /* Release any filtering data we may have accumulated */
963 release_noise_filtering_data(s);
965 /* Reevaluate sampling rates of linked sensors */
966 reapply_sampling_rates(s);
971 /* First enabled sensor on this iio device */
972 sprintf(device_name, DEV_FILE_PATH, dev_num);
973 dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
975 device_fd[dev_num] = dev_fd;
978 ALOGE("Could not open fd on %s (%s)\n", device_name, strerror(errno));
979 adjust_counters(s, 0, from_virtual);
983 ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
985 if (!sensor[s].is_polling) {
987 /* Add this iio device fd to the set of watched fds */
989 ev.data.u32 = dev_num;
991 ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
994 ALOGE("Failed adding %d to poll set (%s)\n", dev_fd, strerror(errno));
998 /* Note: poll-mode fds are not readable */
1002 /* Ensure that on-change sensors send at least one event after enable */
1003 sensor[s].prev_val = -1;
1005 if (sensor[s].is_polling)
1006 start_acquisition_thread(s);
1008 /* Reevaluate sampling rates of linked sensors */
1009 reapply_sampling_rates(s);
1015 static void enable_motion_trigger (int dev_num)
1018 * In the ideal case, we enumerate two triggers per iio device ; the default (periodically firing) trigger, and another one (the motion
1019 * trigger) that only fires up when motion is detected. This second one allows for lesser energy consumption, but requires periodic sample
1020 * duplication at the HAL level for sensors that Android defines as continuous. This "duplicate last sample" logic can only be engaged
1021 * once we got a first sample for the driver, so we start with the default trigger when an iio device is first opened, then adjust the
1022 * trigger when we got events for all active sensors. Unfortunately in the general case several sensors can be associated to a given iio
1023 * device, they can independently be controlled, and we have to adjust the trigger in use at the iio device level depending on whether or
1024 * not appropriate conditions are met at the sensor level.
1029 int active_sensors = trig_sensors_per_dev[dev_num];
1030 int candidate[MAX_SENSORS];
1031 int candidate_count = 0;
1033 if (!active_sensors)
1036 /* Check that all active sensors are ready to switch */
1038 for (s=0; s<MAX_SENSORS; s++)
1039 if (sensor[s].dev_num == dev_num && is_enabled(s) && sensor[s].num_channels &&
1040 (!sensor[s].motion_trigger_name[0] || !sensor[s].report_initialized || is_fast_accelerometer(s) ||
1041 (sensor[s].quirks & QUIRK_FORCE_CONTINUOUS)))
1044 /* Record which particular sensors need to switch */
1046 for (s=0; s<MAX_SENSORS; s++)
1047 if (sensor[s].dev_num == dev_num && is_enabled(s) && sensor[s].num_channels && sensor[s].selected_trigger != sensor[s].motion_trigger_name)
1048 candidate[candidate_count++] = s;
1050 if (!candidate_count)
1053 /* Now engage the motion trigger for sensors which aren't using it */
1055 enable_buffer(dev_num, 0);
1057 for (i=0; i<candidate_count; i++) {
1059 setup_trigger(s, sensor[s].motion_trigger_name);
1062 enable_buffer(dev_num, 1);
1065 static void stamp_reports (int dev_num, int64_t ts)
1069 for (s=0; s<MAX_SENSORS; s++)
1070 if (sensor[s].dev_num == dev_num && is_enabled(s) && !sensor[s].is_polling)
1071 set_report_ts(s, ts);
1075 static int integrate_device_report (int dev_num)
1079 unsigned char buf[MAX_DEVICE_REPORT_SIZE] = { 0 };
1081 unsigned char *target;
1082 unsigned char *source;
1085 int ts_offset = 0; /* Offset of iio timestamp, if provided */
1086 int64_t boot_to_rt_delta;
1088 /* There's an incoming report on the specified iio device char dev fd */
1090 if (dev_num < 0 || dev_num >= MAX_DEVICES) {
1091 ALOGE("Event reported on unexpected iio device %d\n", dev_num);
1095 if (device_fd[dev_num] == -1) {
1096 ALOGE("Ignoring stale report on iio device %d\n", dev_num);
1100 len = read(device_fd[dev_num], buf, expected_dev_report_size[dev_num]);
1103 ALOGE("Could not read report from iio device %d (%s)\n", dev_num, strerror(errno));
1107 ALOGV("Read %d bytes from iio device %d\n", len, dev_num);
1109 /* Map device report to sensor reports */
1111 for (s=0; s<MAX_SENSORS; s++)
1112 if (sensor[s].dev_num == dev_num && is_enabled(s)) {
1116 /* Copy data from device to sensor report buffer */
1117 for (c=0; c<sensor[s].num_channels; c++) {
1119 target = sensor[s].report_buffer + sr_offset;
1121 source = buf + sensor[s].channel[c].offset;
1123 size = sensor[s].channel[c].size;
1125 memcpy(target, source, size);
1130 ALOGV("Sensor %d report available (%d bytes)\n", s, sr_offset);
1132 sensor[s].report_pending = DATA_TRIGGER;
1133 sensor[s].report_initialized = 1;
1135 ts_offset += sr_offset;
1138 /* Tentatively switch to an any-motion trigger if conditions are met */
1139 enable_motion_trigger(dev_num);
1141 /* If no iio timestamp channel was detected for this device, bail out */
1142 if (!has_iio_ts[dev_num]) {
1143 stamp_reports(dev_num, get_timestamp_boot());
1147 /* Don't trust the timestamp channel in any-motion mode */
1148 for (s=0; s<MAX_SENSORS; s++)
1149 if (sensor[s].dev_num == dev_num && is_enabled(s) && sensor[s].selected_trigger == sensor[s].motion_trigger_name) {
1150 stamp_reports(dev_num, get_timestamp_boot());
1154 /* Align on a 64 bits boundary */
1155 ts_offset = expected_dev_report_size[dev_num] - sizeof(int64_t);
1157 /* If we read an amount of data consistent with timestamp presence */
1158 if (len == expected_dev_report_size[dev_num])
1159 ts = *(int64_t*) (buf + ts_offset);
1162 ALOGV("Unreliable timestamp channel on iio dev %d\n", dev_num);
1163 stamp_reports(dev_num, get_timestamp_boot());
1167 ALOGV("Driver timestamp on iio device %d: ts=%lld\n", dev_num, ts);
1169 boot_to_rt_delta = get_timestamp_boot() - get_timestamp_realtime();
1171 stamp_reports(dev_num, ts + boot_to_rt_delta);
1177 static int propagate_vsensor_report (int s, sensors_event_t *data)
1179 /* There's a new report stored in sensor.sample for this sensor; transmit it */
1181 memcpy(data, &sensor[s].sample, sizeof(sensors_event_t));
1184 data->type = sensor[s].type;
1189 static int propagate_sensor_report (int s, sensors_event_t *data)
1191 /* There's a sensor report pending for this sensor ; transmit it */
1193 int num_fields = get_field_count(s);
1195 unsigned char* current_sample;
1198 /* If there's nothing to return... we're done */
1202 ALOGV("Sample on sensor %d (type %d):\n", s, sensor[s].type);
1204 if (sensor[s].is_polling) {
1205 /* We received a good sample but we're not directly enabled so we'll drop */
1206 if (!sensor[s].directly_enabled)
1208 /* Use the data provided by the acquisition thread */
1209 ALOGV("Reporting data from worker thread for S%d\n", s);
1210 memcpy(data, &sensor[s].sample, sizeof(sensors_event_t));
1211 data->timestamp = sensor[s].report_ts;
1215 memset(data, 0, sizeof(sensors_event_t));
1217 data->version = sizeof(sensors_event_t);
1219 data->type = sensor[s].type;
1220 data->timestamp = sensor[s].report_ts;
1222 /* Convert the data into the expected Android-level format */
1224 current_sample = sensor[s].report_buffer;
1226 for (c=0; c<num_fields; c++) {
1228 data->data[c] = sensor[s].ops.transform (s, c, current_sample);
1230 ALOGV("\tfield %d: %g\n", c, data->data[c]);
1231 current_sample += sensor[s].channel[c].size;
1234 ret = sensor[s].ops.finalize(s, data);
1236 /* We will drop samples if the sensor is not directly enabled */
1237 if (!sensor[s].directly_enabled)
1240 /* The finalize routine, in addition to its late sample processing duty, has the final say on whether or not the sample gets sent to Android */
1245 static void synthetize_duplicate_samples (void)
1248 * Some sensor types (ex: gyroscope) are defined as continuously firing by Android, despite the fact that
1249 * we can be dealing with iio drivers that only report events for new samples. For these we generate reports
1250 * periodically, duplicating the last data we got from the driver. This is not necessary for polling sensors.
1258 for (s=0; s<sensor_count; s++) {
1260 /* Ignore disabled sensors */
1264 /* If the sensor is continuously firing, leave it alone */
1265 if (sensor[s].selected_trigger != sensor[s].motion_trigger_name)
1268 /* If we haven't seen a sample, there's nothing to duplicate */
1269 if (!sensor[s].report_initialized)
1272 /* If a sample was recently buffered, leave it alone too */
1273 if (sensor[s].report_pending)
1276 /* We also need a valid sampling rate to be configured */
1277 if (!sensor[s].sampling_rate)
1280 period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
1282 current_ts = get_timestamp_boot();
1283 target_ts = sensor[s].report_ts + period;
1285 if (target_ts <= current_ts) {
1286 /* Mark the sensor for event generation */
1287 set_report_ts(s, current_ts);
1288 sensor[s].report_pending = DATA_DUPLICATE;
1294 static void integrate_thread_report (uint32_t tag)
1296 int s = tag - THREAD_REPORT_TAG_BASE;
1299 len = read(sensor[s].thread_data_fd[0], &sensor[s].sample, sizeof(sensors_event_t));
1301 if (len == sizeof(sensors_event_t))
1302 sensor[s].report_pending = DATA_SYSFS;
1306 static int get_poll_wait_timeout (void)
1309 * Compute an appropriate timeout value, in ms, for the epoll_wait call that's going to await
1310 * for iio device reports and incoming reports from our sensor sysfs data reader threads.
1314 int64_t target_ts = INT64_MAX;
1319 * Check if we're dealing with a driver that only send events when there is motion, despite the fact that the associated Android sensor
1320 * type is continuous rather than on-change. In that case we have to duplicate events. Check deadline for the nearest upcoming event.
1322 for (s=0; s<sensor_count; s++)
1323 if (is_enabled(s) && sensor[s].selected_trigger == sensor[s].motion_trigger_name && sensor[s].sampling_rate) {
1324 period = (int64_t) (1000000000.0 / sensor[s].sampling_rate);
1326 if (sensor[s].report_ts + period < target_ts)
1327 target_ts = sensor[s].report_ts + period;
1330 /* If we don't have such a driver to deal with */
1331 if (target_ts == INT64_MAX)
1332 return -1; /* Infinite wait */
1334 ms_to_wait = (target_ts - get_timestamp_boot()) / 1000000;
1336 /* If the target timestamp is already behind us, don't wait */
1344 int sensor_poll (sensors_event_t* data, int count)
1349 struct epoll_event ev[MAX_DEVICES];
1350 int returned_events;
1353 /* Get one or more events from our collection of sensors */
1354 return_available_sensor_reports:
1356 /* Synthetize duplicate samples if needed */
1357 synthetize_duplicate_samples();
1359 returned_events = 0;
1361 /* Check our sensor collection for available reports */
1362 for (s=0; s<sensor_count && returned_events < count; s++) {
1364 if (sensor[s].report_pending) {
1367 if (sensor[s].is_virtual)
1368 event_count = propagate_vsensor_report(s, &data[returned_events]);
1370 /* Report this event if it looks OK */
1371 event_count = propagate_sensor_report(s, &data[returned_events]);
1374 sensor[s].report_pending = 0;
1375 returned_events += event_count;
1378 * If the sample was deemed invalid or unreportable, e.g. had the same value as the previously reported
1379 * value for a 'on change' sensor, silently drop it.
1383 while (sensor[s].meta_data_pending) {
1384 /* See sensors.h on these */
1385 data[returned_events].version = META_DATA_VERSION;
1386 data[returned_events].sensor = 0;
1387 data[returned_events].type = SENSOR_TYPE_META_DATA;
1388 data[returned_events].reserved0 = 0;
1389 data[returned_events].timestamp = 0;
1390 data[returned_events].meta_data.sensor = s;
1391 data[returned_events].meta_data.what = META_DATA_FLUSH_COMPLETE;
1393 sensor[s].meta_data_pending--;
1397 if (returned_events)
1398 return returned_events;
1402 ALOGV("Awaiting sensor data\n");
1404 nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_wait_timeout());
1407 ALOGE("epoll_wait returned -1 (%s)\n", strerror(errno));
1411 ALOGV("%d fds signalled\n", nfds);
1413 /* For each of the signalled sources */
1414 for (i=0; i<nfds; i++)
1415 if (ev[i].events == EPOLLIN)
1416 switch (ev[i].data.u32) {
1417 case 0 ... MAX_DEVICES-1:
1418 /* Read report from iio char dev fd */
1419 integrate_device_report(ev[i].data.u32);
1422 case THREAD_REPORT_TAG_BASE ...
1423 THREAD_REPORT_TAG_BASE + MAX_SENSORS-1:
1424 /* Get report from acquisition thread */
1425 integrate_thread_report(ev[i].data.u32);
1429 ALOGW("Unexpected event source!\n");
1433 goto return_available_sensor_reports;
1437 int sensor_set_delay (int s, int64_t ns)
1439 float requested_sampling_rate;
1442 ALOGE("Invalid delay requested on sensor %d: %lld\n", s, ns);
1446 requested_sampling_rate = 1000000000.0 / ns;
1448 ALOGV("Entering set delay S%d (%s): current rate: %g, requested: %g\n", s, sensor[s].friendly_name, sensor[s].sampling_rate, requested_sampling_rate);
1451 * Only try to adjust the low level sampling rate if it's different from the current one, as set by the HAL. This saves a few sysfs
1452 * reads and writes as well as buffer enable/disable operations, since at the iio level most drivers require the buffer to be turned off
1453 * in order to accept a sampling rate change. Of course that implies that this field has to be kept up to date and that only this library
1454 * is changing the sampling rate.
1457 if (requested_sampling_rate != sensor[s].sampling_rate)
1458 return sensor_set_rate(s, requested_sampling_rate);
1464 int sensor_flush (int s)
1466 /* If one shot or not enabled return -EINVAL */
1467 if (sensor_desc[s].flags & SENSOR_FLAG_ONE_SHOT_MODE || !is_enabled(s))
1470 sensor[s].meta_data_pending++;
1475 int allocate_control_data (void)
1479 for (i=0; i<MAX_DEVICES; i++)
1482 poll_fd = epoll_create(MAX_DEVICES);
1484 if (poll_fd == -1) {
1485 ALOGE("Can't create epoll instance for iio sensors!\n");
1493 void delete_control_data (void)