#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
+#include <pthread.h>
+#include <time.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <utils/Log.h>
#include "utils.h"
#include "transform.h"
#include "calibration.h"
+#include "description.h"
+#include "filtering.h"
/* Currently active sensors count, per device */
static int poll_sensors_per_dev[MAX_DEVICES]; /* poll-mode sensors */
static int trig_sensors_per_dev[MAX_DEVICES]; /* trigger, event based */
static int device_fd[MAX_DEVICES]; /* fd on the /dev/iio:deviceX file */
-
+static int has_iio_ts[MAX_DEVICES]; /* ts channel available on this iio dev */
+static int expected_dev_report_size[MAX_DEVICES]; /* expected iio scan len */
static int poll_fd; /* epoll instance covering all enabled sensors */
-static int poll_socket_pair[2]; /* used to unblock the poll loop */
+static int active_poll_sensors; /* Number of enabled poll-mode sensors */
-/* Timestamp for the moment when we last exited a poll operation */
-static int64_t last_poll_exit_ts;
+int64_t ts_delta; /* delta between SystemClock.getNanos and our timestamp */
-static int active_poll_sensors; /* Number of enabled poll-mode sensors */
+static int64_t sys_to_rt_delta; /* delta between system and realtime clocks */
-#define INVALID_DEV_NUM ((uint32_t) -1)
+/* We use pthread condition variables to get worker threads out of sleep */
+static pthread_condattr_t thread_cond_attr [MAX_SENSORS];
+static pthread_cond_t thread_release_cond [MAX_SENSORS];
+static pthread_mutex_t thread_release_mutex [MAX_SENSORS];
+/*
+ * We associate tags to each of our poll set entries. These tags have the
+ * following values:
+ * - a iio device number if the fd is a iio character device fd
+ * - THREAD_REPORT_TAG_BASE + sensor handle if the fd is the receiving end of a
+ * pipe used by a sysfs data acquisition thread
+ * */
+#define THREAD_REPORT_TAG_BASE 0x00010000
+
+#define ENABLE_BUFFER_RETRIES 10
+#define ENABLE_BUFFER_RETRY_DELAY_MS 10
static int enable_buffer(int dev_num, int enabled)
{
char sysfs_path[PATH_MAX];
+ int ret, retries, millisec;
+ struct timespec req = {0};
+
+ retries = ENABLE_BUFFER_RETRIES;
+ millisec = ENABLE_BUFFER_RETRY_DELAY_MS;
+ req.tv_sec = 0;
+ req.tv_nsec = millisec * 1000000L;
sprintf(sysfs_path, ENABLE_PATH, dev_num);
- /* Low level, non-multiplexed, enable/disable routine */
- return sysfs_write_int(sysfs_path, enabled);
+ while (retries--) {
+ /* Low level, non-multiplexed, enable/disable routine */
+ ret = sysfs_write_int(sysfs_path, enabled);
+ if (ret > 0)
+ break;
+
+ ALOGE("Failed enabling buffer, retrying");
+ nanosleep(&req, (struct timespec *)NULL);
+ }
+
+ if (ret < 0) {
+ ALOGE("Could not enable buffer\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+
+static int setup_trigger (int s, const char* trigger_val)
+{
+ char sysfs_path[PATH_MAX];
+ int ret = -1, attempts = 5;
+
+ sprintf(sysfs_path, TRIGGER_PATH, sensor_info[s].dev_num);
+
+ if (trigger_val[0] != '\n')
+ ALOGI("Setting S%d (%s) trigger to %s\n", s,
+ sensor_info[s].friendly_name, trigger_val);
+
+ while (ret == -1 && attempts) {
+ ret = sysfs_write_str(sysfs_path, trigger_val);
+ attempts--;
+ }
+
+ if (ret != -1)
+ sensor_info[s].selected_trigger = trigger_val;
+ else
+ ALOGE("Setting S%d (%s) trigger to %s FAILED.\n", s,
+ sensor_info[s].friendly_name, trigger_val);
+ return ret;
}
-static int setup_trigger(int dev_num, const char* trigger_val)
+static void enable_iio_timestamp (int dev_num, int known_channels)
{
+ /* Check if we have a dedicated iio timestamp channel */
+
+ char spec_buf[MAX_TYPE_SPEC_LEN];
char sysfs_path[PATH_MAX];
+ int n;
+
+ sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_type");
+
+ n = sysfs_read_str(sysfs_path, spec_buf, sizeof(spec_buf));
- sprintf(sysfs_path, TRIGGER_PATH, dev_num);
+ if (n <= 0)
+ return;
+
+ if (strcmp(spec_buf, "le:s64/64>>0"))
+ return;
- return sysfs_write_str(sysfs_path, trigger_val);
+ /* OK, type is int64_t as expected, in little endian representation */
+
+ sprintf(sysfs_path, CHANNEL_PATH"%s", dev_num, "in_timestamp_index");
+
+ if (sysfs_read_int(sysfs_path, &n))
+ return;
+
+ /* Check that the timestamp comes after the other fields we read */
+ if (n != known_channels)
+ return;
+
+ /* Try enabling that channel */
+ sprintf(sysfs_path, CHANNEL_PATH "%s", dev_num, "in_timestamp_en");
+
+ sysfs_write_int(sysfs_path, 1);
+
+ if (sysfs_read_int(sysfs_path, &n))
+ return;
+
+ if (n) {
+ ALOGI("Detected timestamp channel on iio device %d\n", dev_num);
+ has_iio_ts[dev_num] = 1;
+ }
}
-void build_sensor_report_maps(int dev_num)
+void build_sensor_report_maps (int dev_num)
{
/*
* Read sysfs files from a iio device's scan_element directory, and
known_channels++;
}
+ /* Stop sampling - if we are recovering from hal restart */
+ enable_buffer(dev_num, 0);
+ setup_trigger(s, "\n");
+
/* Turn on channels we're aware of */
for (c=0;c<sensor_info[s].num_channels; c++) {
sprintf(sysfs_path, CHANNEL_PATH "%s",
sensor_info[s].dev_num,
sensor_catalog[i].channel[c].en_path);
-
sysfs_write_int(sysfs_path, 1);
}
}
offset += size;
}
+
+ /* Enable the timestamp channel if there is one available */
+ enable_iio_timestamp(dev_num, known_channels);
+
+ /* Add padding and timestamp size if it's enabled on this iio device */
+ if (has_iio_ts[dev_num])
+ offset = (offset+7)/8*8 + sizeof(int64_t);
+
+ expected_dev_report_size[dev_num] = offset;
+ ALOGI("Expecting %d scan length on iio dev %d\n", offset, dev_num);
+
+ if (expected_dev_report_size[dev_num] > MAX_DEVICE_REPORT_SIZE) {
+ ALOGE("Unexpectedly large scan buffer on iio dev%d: %d bytes\n",
+ dev_num, expected_dev_report_size[dev_num]);
+
+ expected_dev_report_size[dev_num] = MAX_DEVICE_REPORT_SIZE;
+ }
}
*/
int dev_num = sensor_info[s].dev_num;
- int catalog_index = sensor_info[s].catalog_index;
- int sensor_type = sensor_catalog[catalog_index].type;
/* Refcount per sensor, in terms of enable count */
if (enabled) {
ALOGI("Enabling sensor %d (iio device %d: %s)\n",
s, dev_num, sensor_info[s].friendly_name);
- sensor_info[s].enable_count++;
-
- if (sensor_info[s].enable_count != 1) {
+ if (sensor_info[s].enabled)
return 0; /* The sensor was, and remains, in use */
- } else {
- if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
- compass_read_data(COMPASS_CALIBRATION_PATH);
- if (sensor_type == SENSOR_TYPE_GYROSCOPE)
+ sensor_info[s].enabled = 1;
+
+ switch (sensor_info[s].type) {
+ case SENSOR_TYPE_MAGNETIC_FIELD:
+ compass_read_data(&sensor_info[s]);
+ break;
+
+ case SENSOR_TYPE_GYROSCOPE:
+ case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
gyro_cal_init(&sensor_info[s]);
+ break;
}
} else {
- if (sensor_info[s].enable_count == 0)
- return -1; /* Spurious disable call */
+ if (sensor_info[s].enabled == 0)
+ return 0; /* Spurious disable call */
ALOGI("Disabling sensor %d (iio device %d: %s)\n", s, dev_num,
sensor_info[s].friendly_name);
- if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
- compass_store_data(COMPASS_CALIBRATION_PATH);
-
- sensor_info[s].enable_count--;
-
- if (sensor_info[s].enable_count > 0)
- return 0; /* The sensor was, and remains, in use */
+ sensor_info[s].enabled = 0;
/* Sensor disabled, lower report available flag */
sensor_info[s].report_pending = 0;
+
+ if (sensor_info[s].type == SENSOR_TYPE_MAGNETIC_FIELD)
+ compass_store_data(&sensor_info[s]);
+
+ if(sensor_info[s].type == SENSOR_TYPE_GYROSCOPE ||
+ sensor_info[s].type == SENSOR_TYPE_GYROSCOPE_UNCALIBRATED)
+ gyro_store_data(&sensor_info[s]);
}
+
+ /* If uncalibrated type and pair is already active don't adjust counters */
+ if (sensor_info[s].type == SENSOR_TYPE_GYROSCOPE_UNCALIBRATED &&
+ sensor_info[sensor_info[s].pair_idx].enabled != 0)
+ return 0;
+
/* We changed the state of a sensor - adjust per iio device counters */
/* If this is a regular event-driven sensor */
}
+static int get_field_count (int s)
+{
+ switch (sensor_info[s].type) {
+ case SENSOR_TYPE_ACCELEROMETER: /* m/s^2 */
+ case SENSOR_TYPE_MAGNETIC_FIELD: /* micro-tesla */
+ case SENSOR_TYPE_ORIENTATION: /* degrees */
+ case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
+ case SENSOR_TYPE_GYROSCOPE: /* radians/s */
+ return 3;
+
+ case SENSOR_TYPE_LIGHT: /* SI lux units */
+ case SENSOR_TYPE_AMBIENT_TEMPERATURE: /* °C */
+ case SENSOR_TYPE_TEMPERATURE: /* °C */
+ case SENSOR_TYPE_PROXIMITY: /* centimeters */
+ case SENSOR_TYPE_PRESSURE: /* hecto-pascal */
+ case SENSOR_TYPE_RELATIVE_HUMIDITY: /* percent */
+ return 1;
+
+ case SENSOR_TYPE_ROTATION_VECTOR:
+ return 4;
+
+ default:
+ ALOGE("Unknown sensor type!\n");
+ return 0; /* Drop sample */
+ }
+}
+
+
+static void* acquisition_routine (void* param)
+{
+ /*
+ * Data acquisition routine run in a dedicated thread, covering a single
+ * sensor. This loop will periodically retrieve sampling data through
+ * 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
+ * frequently, as the thread may be disposed of at any time. Note that
+ * Bionic does not provide pthread_cancel / pthread_testcancel...
+ */
+
+ int s = (int) (size_t) param;
+ int num_fields, sample_size;
+ struct sensors_event_t data = {0};
+ int c;
+ int ret;
+ struct timespec target_time;
+ int64_t timestamp, period, start, stop;
+
+ if (s < 0 || s >= sensor_count) {
+ ALOGE("Invalid sensor handle!\n");
+ return NULL;
+ }
+
+ ALOGI("Entering data acquisition thread S%d (%s): rate(%f), ts(%lld)\n", s,
+ sensor_info[s].friendly_name, sensor_info[s].sampling_rate, sensor_info[s].report_ts);
+
+ if (sensor_info[s].sampling_rate <= 0) {
+ ALOGE("Non-positive rate in acquisition routine for sensor %d: %f\n",
+ s, sensor_info[s].sampling_rate);
+ return NULL;
+ }
+
+ num_fields = get_field_count(s);
+ sample_size = sizeof(int64_t) + num_fields * sizeof(float);
+
+ /*
+ * 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
+ * variables to get the acquisition threads out of sleep quickly after
+ * the sampling rate is adjusted, or the sensor is disabled.
+ */
+ pthread_mutex_lock(&thread_release_mutex[s]);
+
+ /* Pinpoint the moment we start sampling */
+ timestamp = get_timestamp_monotonic();
+
+ /* Check and honor termination requests */
+ while (sensor_info[s].thread_data_fd[1] != -1) {
+ start = get_timestamp();
+ /* Read values through sysfs */
+ for (c=0; c<num_fields; c++) {
+ data.data[c] = acquire_immediate_value(s, c);
+ /* Check and honor termination requests */
+ if (sensor_info[s].thread_data_fd[1] == -1)
+ goto exit;
+ }
+ stop = get_timestamp();
+ data.timestamp = start/2 + stop/2;
+
+ /* If the sample looks good */
+ if (sensor_info[s].ops.finalize(s, &data)) {
+
+ /* Pipe it for transmission to poll loop */
+ ret = write( sensor_info[s].thread_data_fd[1],
+ &data.timestamp, sample_size);
+
+ if (ret != sample_size)
+ ALOGE("S%d acquisition thread: tried to write %d, ret: %d\n",
+ s, sample_size, ret);
+ }
+
+ /* Check and honor termination requests */
+ if (sensor_info[s].thread_data_fd[1] == -1)
+ goto exit;
+
+ /* Recalculate period asumming sensor_info[s].sampling_rate
+ * can be changed dynamically during the thread run */
+ if (sensor_info[s].sampling_rate <= 0) {
+ ALOGE("Non-positive rate in acquisition routine for sensor %d: %f\n",
+ s, sensor_info[s].sampling_rate);
+ goto exit;
+ }
+
+ period = (int64_t) (1000000000LL / sensor_info[s].sampling_rate);
+ timestamp += period;
+ set_timestamp(&target_time, timestamp);
+
+ /*
+ * Wait until the sampling time elapses, or a rate change is
+ * signaled, or a thread exit is requested.
+ */
+ ret = pthread_cond_timedwait( &thread_release_cond[s],
+ &thread_release_mutex[s],
+ &target_time);
+ }
+
+exit:
+ ALOGV("Acquisition thread for S%d exiting\n", s);
+ pthread_mutex_unlock(&thread_release_mutex[s]);
+ pthread_exit(0);
+ return NULL;
+}
+
+
+static void start_acquisition_thread (int s)
+{
+ int incoming_data_fd;
+ int ret;
+
+ struct epoll_event ev = {0};
+
+ ALOGV("Initializing acquisition context for sensor %d\n", s);
+
+ /* Create condition variable and mutex for quick thread release */
+ ret = pthread_condattr_init(&thread_cond_attr[s]);
+ ret = pthread_condattr_setclock(&thread_cond_attr[s], CLOCK_MONOTONIC);
+ ret = pthread_cond_init(&thread_release_cond[s], &thread_cond_attr[s]);
+ ret = pthread_mutex_init(&thread_release_mutex[s], NULL);
+
+ /* Create a pipe for inter thread communication */
+ ret = pipe(sensor_info[s].thread_data_fd);
+
+ incoming_data_fd = sensor_info[s].thread_data_fd[0];
+
+ ev.events = EPOLLIN;
+ ev.data.u32 = THREAD_REPORT_TAG_BASE + s;
+
+ /* Add incoming side of pipe to our poll set, with a suitable tag */
+ ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, incoming_data_fd , &ev);
+
+ /* Create and start worker thread */
+ ret = pthread_create( &sensor_info[s].acquisition_thread,
+ NULL,
+ acquisition_routine,
+ (void*) (size_t) s);
+}
+
+
+static void stop_acquisition_thread (int s)
+{
+ int incoming_data_fd = sensor_info[s].thread_data_fd[0];
+ int outgoing_data_fd = sensor_info[s].thread_data_fd[1];
+
+ ALOGV("Tearing down acquisition context for sensor %d\n", s);
+
+ /* Delete the incoming side of the pipe from our poll set */
+ epoll_ctl(poll_fd, EPOLL_CTL_DEL, incoming_data_fd, NULL);
+
+ /* Mark the pipe ends as invalid ; that's a cheap exit flag */
+ sensor_info[s].thread_data_fd[0] = -1;
+ sensor_info[s].thread_data_fd[1] = -1;
+
+ /* Close both sides of our pipe */
+ close(incoming_data_fd);
+ close(outgoing_data_fd);
+
+ /* Stop acquisition thread and clean up thread handle */
+ pthread_cond_signal(&thread_release_cond[s]);
+ pthread_join(sensor_info[s].acquisition_thread, NULL);
+
+ /* Clean up our sensor descriptor */
+ sensor_info[s].acquisition_thread = -1;
+
+ /* Delete condition variable and mutex */
+ pthread_cond_destroy(&thread_release_cond[s]);
+ pthread_mutex_destroy(&thread_release_mutex[s]);
+}
+
+
int sensor_activate(int s, int enabled)
{
char device_name[PATH_MAX];
- char trigger_name[MAX_NAME_SIZE + 16];
- int c;
struct epoll_event ev = {0};
int dev_fd;
int ret;
int dev_num = sensor_info[s].dev_num;
- int i = sensor_info[s].catalog_index;
int is_poll_sensor = !sensor_info[s].num_channels;
+ /* Prepare the report timestamp field for the first event, see set_report_ts method */
+ sensor_info[s].report_ts = 0;
+ ts_delta = load_timestamp_sys_clock() - get_timestamp_monotonic();
+ sys_to_rt_delta = get_timestamp_realtime - load_timestamp_sys_clock();
+
+
+ /* If we want to activate gyro calibrated and gyro uncalibrated is activated
+ * Deactivate gyro uncalibrated - Uncalibrated releases handler
+ * Activate gyro calibrated - Calibrated has handler
+ * Reactivate gyro uncalibrated - Uncalibrated gets data from calibrated */
+
+ /* If we want to deactivate gyro calibrated and gyro uncalibrated is active
+ * Deactivate gyro uncalibrated - Uncalibrated no longer gets data from handler
+ * Deactivate gyro calibrated - Calibrated releases handler
+ * Reactivate gyro uncalibrated - Uncalibrated has handler */
+
+ if (sensor_info[s].type == SENSOR_TYPE_GYROSCOPE &&
+ sensor_info[s].pair_idx && sensor_info[sensor_info[s].pair_idx].enabled != 0) {
+
+ sensor_activate(sensor_info[s].pair_idx, 0);
+ ret = sensor_activate(s, enabled);
+ sensor_activate(sensor_info[s].pair_idx, 1);
+ return ret;
+ }
+
ret = adjust_counters(s, enabled);
/* If the operation was neutral in terms of state, we're done */
if (ret <= 0)
return ret;
+ sensor_info[s].event_count = 0;
+ sensor_info[s].meta_data_pending = 0;
+
+ if (enabled && (sensor_info[s].quirks & QUIRK_NOISY))
+ /* Initialize filtering data if required */
+ setup_noise_filtering(s);
+
if (!is_poll_sensor) {
/* Stop sampling */
enable_buffer(dev_num, 0);
- setup_trigger(dev_num, "\n");
+ setup_trigger(s, "\n");
/* If there's at least one sensor enabled on this iio device */
if (trig_sensors_per_dev[dev_num]) {
- sprintf(trigger_name, "%s-dev%d",
- sensor_info[s].internal_name, dev_num);
/* Start sampling */
- setup_trigger(dev_num, trigger_name);
+ setup_trigger(s, sensor_info[s].init_trigger_name);
enable_buffer(dev_num, 1);
}
}
/*
* Make sure we have a fd on the character device ; conversely, close
- * the fd if no one is using associated sensor anymore. The assumption
+ * the fd if no one is using associated sensors anymore. The assumption
* here is that the underlying driver will power on the relevant
- * hardware block while someone hold a fd on the device.
+ * hardware block while someone holds a fd on the device.
*/
dev_fd = device_fd[dev_num];
if (!enabled) {
+ if (is_poll_sensor)
+ stop_acquisition_thread(s);
+
if (dev_fd != -1 && !poll_sensors_per_dev[dev_num] &&
!trig_sensors_per_dev[dev_num]) {
/*
close(dev_fd);
device_fd[dev_num] = -1;
}
+
+ /* Release any filtering data we may have accumulated */
+ release_noise_filtering_data(s);
+
return 0;
}
}
}
- /* Release the polling loop so an updated timeout gets used */
- write(poll_socket_pair[1], "", 1);
+ /* Ensure that on-change sensors send at least one event after enable */
+ sensor_info[s].prev_val = -1;
+
+ if (is_poll_sensor)
+ start_acquisition_thread(s);
return 0;
}
-static int integrate_device_report(int dev_num)
+static int is_fast_accelerometer (int s)
+{
+ /*
+ * Some games don't react well to accelerometers using any-motion
+ * triggers. Even very low thresholds seem to trip them, and they tend
+ * to request fairly high event rates. Favor continuous triggers if the
+ * sensor is an accelerometer and uses a sampling rate of at least 25.
+ */
+
+ if (sensor_info[s].type != SENSOR_TYPE_ACCELEROMETER)
+ return 0;
+
+ if (sensor_info[s].sampling_rate < 25)
+ return 0;
+
+ return 1;
+}
+
+
+static void enable_motion_trigger (int dev_num)
+{
+ /*
+ * In the ideal case, we enumerate two triggers per iio device ; the
+ * default (periodically firing) trigger, and another one (the motion
+ * trigger) that only fires up when motion is detected. This second one
+ * allows for lesser energy consumption, but requires periodic sample
+ * duplication at the HAL level for sensors that Android defines as
+ * continuous. This "duplicate last sample" logic can only be engaged
+ * 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
+ * trigger when we got events for all active sensors. Unfortunately in
+ * the general case several sensors can be associated to a given iio
+ * device, they can independently be controlled, and we have to adjust
+ * the trigger in use at the iio device level depending on whether or
+ * not appropriate conditions are met at the sensor level.
+ */
+
+ int s;
+ int i;
+ int active_sensors = trig_sensors_per_dev[dev_num];
+ int candidate[MAX_SENSORS];
+ int candidate_count = 0;
+
+ if (!active_sensors)
+ return;
+
+ /* Check that all active sensors are ready to switch */
+
+ for (s=0; s<MAX_SENSORS; s++)
+ if (sensor_info[s].dev_num == dev_num &&
+ sensor_info[s].enabled &&
+ sensor_info[s].num_channels &&
+ (!sensor_info[s].motion_trigger_name[0] ||
+ !sensor_info[s].report_initialized ||
+ is_fast_accelerometer(s) ||
+ (sensor_info[s].quirks & QUIRK_FORCE_CONTINUOUS))
+ )
+ return; /* Nope */
+
+ /* Record which particular sensors need to switch */
+
+ for (s=0; s<MAX_SENSORS; s++)
+ if (sensor_info[s].dev_num == dev_num &&
+ sensor_info[s].enabled &&
+ sensor_info[s].num_channels &&
+ sensor_info[s].selected_trigger !=
+ sensor_info[s].motion_trigger_name)
+ candidate[candidate_count++] = s;
+
+ if (!candidate_count)
+ return;
+
+ /* Now engage the motion trigger for sensors which aren't using it */
+
+ enable_buffer(dev_num, 0);
+
+ for (i=0; i<candidate_count; i++) {
+ s = candidate[i];
+ setup_trigger(s, sensor_info[s].motion_trigger_name);
+ }
+
+ enable_buffer(dev_num, 1);
+}
+
+/* CTS acceptable thresholds:
+ * EventGapVerification.java: (th <= 1.8)
+ * FrequencyVerification.java: (0.9)*(expected freq) => (th <= 1.1111)
+ */
+#define THRESHOLD 1.10
+#define MAX_DELAY 500000000 /* 500 ms */
+void set_report_ts(int s, int64_t ts)
+{
+ int64_t maxTs, period;
+ int catalog_index = sensor_info[s].catalog_index;
+ int is_accel = (sensor_catalog[catalog_index].type == SENSOR_TYPE_ACCELEROMETER);
+
+ /*
+ * A bit of a hack to please a bunch of cts tests. They
+ * expect the timestamp to be exacly according to the set-up
+ * frequency but if we're simply getting the timestamp at hal level
+ * this may not be the case. Perhaps we'll get rid of this when
+ * we'll be reading the timestamp from the iio channel for all sensors
+ */
+ if (sensor_info[s].report_ts && sensor_info[s].sampling_rate &&
+ REPORTING_MODE(sensor_desc[s].flags) == SENSOR_FLAG_CONTINUOUS_MODE)
+ {
+ period = (int64_t) (1000000000LL / sensor_info[s].sampling_rate);
+ maxTs = sensor_info[s].report_ts + (is_accel ? 1 : THRESHOLD) * period;
+ /* If we're too far behind get back on track */
+ if (ts - maxTs >= MAX_DELAY)
+ maxTs = ts;
+ sensor_info[s].report_ts = (ts < maxTs ? ts : maxTs);
+ } else {
+ sensor_info[s].report_ts = ts;
+ }
+}
+
+
+static int integrate_device_report (int dev_num)
{
int len;
int s,c;
- unsigned char buf[MAX_SENSOR_REPORT_SIZE] = { 0 };
+ unsigned char buf[MAX_DEVICE_REPORT_SIZE] = { 0 };
int sr_offset;
unsigned char *target;
unsigned char *source;
int size;
- int ts;
+ int64_t ts = 0;
+ int ts_offset = 0; /* Offset of iio timestamp, if provided */
- /* There's an incoming report on the specified fd */
+ /* There's an incoming report on the specified iio device char dev fd */
if (dev_num < 0 || dev_num >= MAX_DEVICES) {
ALOGE("Event reported on unexpected iio device %d\n", dev_num);
return -1;
}
- ts = get_timestamp();
-
- len = read(device_fd[dev_num], buf, MAX_SENSOR_REPORT_SIZE);
+ len = read(device_fd[dev_num], buf, expected_dev_report_size[dev_num]);
if (len == -1) {
ALOGE("Could not read report from iio device %d (%s)\n",
ALOGV("Read %d bytes from iio device %d\n", len, dev_num);
+ /* Map device report to sensor reports */
+
for (s=0; s<MAX_SENSORS; s++)
if (sensor_info[s].dev_num == dev_num &&
- sensor_info[s].enable_count) {
+ sensor_info[s].enabled) {
sr_offset = 0;
ALOGV("Sensor %d report available (%d bytes)\n", s,
sr_offset);
- sensor_info[s].report_ts = ts;
- sensor_info[s].report_pending = 1;
+ sensor_info[s].report_pending = DATA_TRIGGER;
+ sensor_info[s].report_initialized = 1;
+ set_report_ts(s, get_timestamp());
+
+ ts_offset += sr_offset;
}
- return 0;
-}
+ /* Tentatively switch to an any-motion trigger if conditions are met */
+ enable_motion_trigger(dev_num);
+ /* If no iio timestamp channel was detected for this device, bail out */
+ if (!has_iio_ts[dev_num])
+ return 0;
-static void propagate_sensor_report(int s, struct sensors_event_t* data)
-{
- /* There's a sensor report pending for this sensor ; transmit it */
+ /* Align on a 64 bits boundary */
+ ts_offset = (ts_offset + 7)/8*8;
- int catalog_index = sensor_info[s].catalog_index;
- int sensor_type = sensor_catalog[catalog_index].type;
- int num_fields;
- int c;
- unsigned char* current_sample;
- int64_t current_ts = get_timestamp();
+ /* If we read an amount of data consistent with timestamp presence */
+ if (len == expected_dev_report_size[dev_num])
+ ts = *(int64_t*) (buf + ts_offset);
- memset(data, 0, sizeof(sensors_event_t));
+ if (ts == 0) {
+ ALOGV("Unreliable timestamp channel on iio dev %d\n", dev_num);
+ return 0;
+ }
- data->version = sizeof(sensors_event_t);
- data->sensor = s;
- data->type = sensor_type;
+ ALOGV("Driver timestamp on iio device %d: ts=%lld\n", dev_num, ts);
- if (sensor_info[s].report_ts)
- data->timestamp = sensor_info[s].report_ts;
- else
- data->timestamp = current_ts;
+ for (s=0; s<MAX_SENSORS; s++)
+ if (sensor_info[s].dev_num == dev_num && sensor_info[s].enabled)
+ set_report_ts(s, ts - sys_to_rt_delta);
- switch (sensor_type) {
- case SENSOR_TYPE_ACCELEROMETER: /* m/s^2 */
- case SENSOR_TYPE_MAGNETIC_FIELD: /* micro-tesla */
- case SENSOR_TYPE_ORIENTATION: /* degrees */
- case SENSOR_TYPE_GYROSCOPE: /* radians/s */
- num_fields = 3;
- break;
+ return 0;
+}
- case SENSOR_TYPE_LIGHT: /* SI lux units */
- case SENSOR_TYPE_AMBIENT_TEMPERATURE: /* °C */
- case SENSOR_TYPE_TEMPERATURE: /* °C */
- case SENSOR_TYPE_PROXIMITY: /* centimeters */
- case SENSOR_TYPE_PRESSURE: /* hecto-pascal */
- case SENSOR_TYPE_RELATIVE_HUMIDITY: /* percent */
- num_fields = 1;
- break;
- case SENSOR_TYPE_ROTATION_VECTOR:
- num_fields = 4;
- break;
+static int propagate_sensor_report (int s, struct sensors_event_t *data)
+{
+ /* There's a sensor report pending for this sensor ; transmit it */
- case SENSOR_TYPE_DEVICE_PRIVATE_BASE: /* hidden for now */
- num_fields = 0;
- break;
+ int num_fields = get_field_count(s);
+ int c;
+ unsigned char* current_sample;
- default:
- ALOGE("Unknown sensor type!\n");
- num_fields = 0;
- break;
- }
+ /* If there's nothing to return... we're done */
+ if (!num_fields)
+ return 0;
- ALOGV("Sample on sensor %d (type %d):\n", s, sensor_type);
- /* Take note of current time counter value for rate control purposes */
- sensor_info[s].last_integration_ts = current_ts;
+ /* Only return uncalibrated event if also gyro active */
+ if (sensor_info[s].type == SENSOR_TYPE_GYROSCOPE_UNCALIBRATED &&
+ sensor_info[sensor_info[s].pair_idx].enabled != 0)
+ return 0;
- /* If we're dealing with a poll-mode sensor */
- if (!sensor_info[s].num_channels) {
+ memset(data, 0, sizeof(sensors_event_t));
- /* Read values through sysfs rather than from a report buffer */
- for (c=0; c<num_fields; c++) {
+ data->version = sizeof(sensors_event_t);
+ data->sensor = s;
+ data->type = sensor_info[s].type;
+ data->timestamp = sensor_info[s].report_ts;
- data->data[c] = acquire_immediate_value(s, c);
+ ALOGV("Sample on sensor %d (type %d):\n", s, sensor_info[s].type);
- ALOGV("\tfield %d: %f\n", c, data->data[c]);
- }
+ current_sample = sensor_info[s].report_buffer;
- sensor_info[s].ops.finalize(s, data);
- return;
+ /* If this is a poll sensor */
+ if (!sensor_info[s].num_channels) {
+ /* Use the data provided by the acquisition thread */
+ ALOGV("Reporting data from worker thread for S%d\n", s);
+ memcpy(data->data, current_sample, num_fields * sizeof(float));
+ return 1;
}
/* Convert the data into the expected Android-level format */
-
- current_sample = sensor_info[s].report_buffer;
-
for (c=0; c<num_fields; c++) {
data->data[c] = sensor_info[s].ops.transform
current_sample += sensor_info[s].channel[c].size;
}
- sensor_info[s].ops.finalize(s, data);
+ /*
+ * 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.
+ */
+ return sensor_info[s].ops.finalize(s, data);
}
-static int get_poll_time (void)
+static void synthetize_duplicate_samples (void)
{
- int64_t target_ts;
- int64_t lowest_target_ts;
- int64_t current_ts;
+ /*
+ * Some sensor types (ex: gyroscope) are defined as continuously firing
+ * by Android, despite the fact that we can be dealing with iio drivers
+ * that only report events for new samples. For these we generate
+ * reports periodically, duplicating the last data we got from the
+ * driver. This is not necessary for polling sensors.
+ */
+
int s;
+ int64_t current_ts;
+ int64_t target_ts;
+ int64_t period;
- if (!active_poll_sensors)
- return -1; /* Infinite wait */
+ for (s=0; s<sensor_count; s++) {
- /* Check if we should schedule a poll-mode sensor event delivery */
+ /* Ignore disabled sensors */
+ if (!sensor_info[s].enabled)
+ continue;
- lowest_target_ts = INT64_MAX;
+ /* If the sensor is continuously firing, leave it alone */
+ if (sensor_info[s].selected_trigger !=
+ sensor_info[s].motion_trigger_name)
+ continue;
- for (s=0; s<sensor_count; s++)
- if (sensor_info[s].enable_count &&
- sensor_info[s].sampling_rate &&
- !sensor_info[s].num_channels) {
- target_ts = sensor_info[s].last_integration_ts +
- 1000000000LL/sensor_info[s].sampling_rate;
-
- if (target_ts < lowest_target_ts)
- lowest_target_ts = target_ts;
- }
+ /* If we haven't seen a sample, there's nothing to duplicate */
+ if (!sensor_info[s].report_initialized)
+ continue;
- if (lowest_target_ts == INT64_MAX)
- return -1;
+ /* If a sample was recently buffered, leave it alone too */
+ if (sensor_info[s].report_pending)
+ continue;
- current_ts = get_timestamp();
+ /* We also need a valid sampling rate to be configured */
+ if (!sensor_info[s].sampling_rate)
+ continue;
- if (lowest_target_ts <= current_ts)
- return 0;
+ period = (int64_t) (1000000000.0/ sensor_info[s].sampling_rate);
- return (lowest_target_ts - current_ts)/1000000; /* ms */
+ current_ts = get_timestamp();
+ target_ts = sensor_info[s].report_ts + period;
+
+ if (target_ts <= current_ts) {
+ /* Mark the sensor for event generation */
+ set_report_ts(s, current_ts);
+ sensor_info[s].report_pending = DATA_DUPLICATE;
+ }
+ }
}
-static void acknowledge_release (void)
+static void integrate_thread_report (uint32_t tag)
{
- /* A write to our socket circuit was performed to release epoll */
- char buf;
- read(poll_socket_pair[0], &buf, 1);
+ int s = tag - THREAD_REPORT_TAG_BASE;
+ int len;
+ int expected_len;
+ int64_t timestamp;
+ unsigned char current_sample[MAX_SENSOR_REPORT_SIZE];
+
+ expected_len = sizeof(int64_t) + get_field_count(s) * sizeof(float);
+
+ len = read(sensor_info[s].thread_data_fd[0],
+ current_sample,
+ expected_len);
+
+ memcpy(×tamp, current_sample, sizeof(int64_t));
+ memcpy(sensor_info[s].report_buffer, sizeof(int64_t) + current_sample,
+ expected_len - sizeof(int64_t));
+
+ if (len == expected_len) {
+ set_report_ts(s, timestamp);
+ sensor_info[s].report_pending = DATA_SYSFS;
+ }
+}
+
+
+static int get_poll_wait_timeout (void)
+{
+ /*
+ * Compute an appropriate timeout value, in ms, for the epoll_wait
+ * call that's going to await for iio device reports and incoming
+ * reports from our sensor sysfs data reader threads.
+ */
+
+ int s;
+ int64_t target_ts = INT64_MAX;
+ int64_t ms_to_wait;
+ int64_t period;
+
+ /*
+ * Check if we're dealing with a driver that only send events when
+ * there is motion, despite the fact that the associated Android sensor
+ * type is continuous rather than on-change. In that case we have to
+ * duplicate events. Check deadline for the nearest upcoming event.
+ */
+ for (s=0; s<sensor_count; s++)
+ if (sensor_info[s].enabled &&
+ sensor_info[s].selected_trigger ==
+ sensor_info[s].motion_trigger_name &&
+ sensor_info[s].sampling_rate) {
+ period = (int64_t) (1000000000.0 /
+ sensor_info[s].sampling_rate);
+
+ if (sensor_info[s].report_ts + period < target_ts)
+ target_ts = sensor_info[s].report_ts + period;
+ }
+
+ /* If we don't have such a driver to deal with */
+ if (target_ts == INT64_MAX)
+ return -1; /* Infinite wait */
+
+ ms_to_wait = (target_ts - get_timestamp()) / 1000000;
+
+ /* If the target timestamp is already behind us, don't wait */
+ if (ms_to_wait < 1)
+ return 0;
+
+ return ms_to_wait;
}
int s;
int i;
int nfds;
- int delta;
struct epoll_event ev[MAX_DEVICES];
- int64_t target_ts;
+ int returned_events;
+ int event_count;
+ int uncal_start;
/* Get one or more events from our collection of sensors */
-return_first_available_sensor_report:
+return_available_sensor_reports:
- /* If there's at least one available report */
- for (s=0; s<sensor_count; s++)
+ /* Synthetize duplicate samples if needed */
+ synthetize_duplicate_samples();
+
+ returned_events = 0;
+
+ /* Check our sensor collection for available reports */
+ for (s=0; s<sensor_count && returned_events < count; s++) {
if (sensor_info[s].report_pending) {
+ event_count = 0;
+
+ /* Report this event if it looks OK */
+ event_count = propagate_sensor_report(s, &data[returned_events]);
- /* Return that up */
- propagate_sensor_report(s, data);
+ /* Lower flag */
sensor_info[s].report_pending = 0;
- ALOGV("Report on sensor %d\n", s);
- return 1;
+
+ /* Duplicate only if both cal & uncal are active */
+ if (sensor_info[s].type == SENSOR_TYPE_GYROSCOPE &&
+ sensor_info[s].pair_idx && sensor_info[sensor_info[s].pair_idx].enabled != 0) {
+ struct gyro_cal* gyro_data = (struct gyro_cal*) sensor_info[s].cal_data;
+
+ memcpy(&data[returned_events + event_count], &data[returned_events],
+ sizeof(struct sensors_event_t) * event_count);
+
+ uncal_start = returned_events + event_count;
+ for (i = 0; i < event_count; i++) {
+ data[uncal_start + i].type = SENSOR_TYPE_GYROSCOPE_UNCALIBRATED;
+ data[uncal_start + i].sensor = sensor_info[s].pair_idx;
+
+ data[uncal_start + i].data[0] = data[returned_events + i].data[0] + gyro_data->bias_x;
+ data[uncal_start + i].data[1] = data[returned_events + i].data[1] + gyro_data->bias_y;
+ data[uncal_start + i].data[2] = data[returned_events + i].data[2] + gyro_data->bias_z;
+
+ data[uncal_start + i].uncalibrated_gyro.bias[0] = gyro_data->bias_x;
+ data[uncal_start + i].uncalibrated_gyro.bias[1] = gyro_data->bias_y;
+ data[uncal_start + i].uncalibrated_gyro.bias[2] = gyro_data->bias_z;
+ }
+ event_count <<= 1;
+ }
+ sensor_info[sensor_info[s].pair_idx].report_pending = 0;
+ returned_events += event_count;
+ /*
+ * If the sample was deemed invalid or unreportable,
+ * e.g. had the same value as the previously reported
+ * value for a 'on change' sensor, silently drop it.
+ */
+ }
+ while (sensor_info[s].meta_data_pending) {
+ /* See sensors.h on these */
+ data[returned_events].version = META_DATA_VERSION;
+ data[returned_events].sensor = 0;
+ data[returned_events].type = SENSOR_TYPE_META_DATA;
+ data[returned_events].reserved0 = 0;
+ data[returned_events].timestamp = 0;
+ data[returned_events].meta_data.sensor = s;
+ data[returned_events].meta_data.what = META_DATA_FLUSH_COMPLETE;
+ returned_events++;
+ sensor_info[s].meta_data_pending--;
}
+ }
+ if (returned_events)
+ return returned_events;
+
await_event:
ALOGV("Awaiting sensor data\n");
- nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_time());
-
- last_poll_exit_ts = get_timestamp();
+ nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_wait_timeout());
if (nfds == -1) {
- ALOGI("epoll_wait returned -1 (%s)\n", strerror(errno));
+ ALOGE("epoll_wait returned -1 (%s)\n", strerror(errno));
goto await_event;
}
ALOGV("%d fds signalled\n", nfds);
- /* For each of the devices for which a report is available */
+ /* For each of the signalled sources */
for (i=0; i<nfds; i++)
- if (ev[i].events == EPOLLIN) {
- if (ev[i].data.u32 == INVALID_DEV_NUM) {
- acknowledge_release();
- goto await_event;
- } else
- /* Read report */
- integrate_device_report(ev[i].data.u32);
- }
-
- /* Check poll-mode sensors and fire up an event if it's time to do so */
- if (active_poll_sensors)
- for (s=0; s<sensor_count; s++)
- if (sensor_info[s].enable_count &&
- !sensor_info[s].num_channels &&
- sensor_info[s].sampling_rate) {
- target_ts = sensor_info[s].last_integration_ts +
- 1000000000LL/sensor_info[s].sampling_rate;
-
- if (last_poll_exit_ts >= target_ts)
- sensor_info[s].report_pending = 1;
+ if (ev[i].events == EPOLLIN)
+ switch (ev[i].data.u32) {
+ case 0 ... MAX_DEVICES-1:
+ /* Read report from iio char dev fd */
+ integrate_device_report(ev[i].data.u32);
+ break;
+
+ case THREAD_REPORT_TAG_BASE ...
+ THREAD_REPORT_TAG_BASE + MAX_SENSORS-1:
+ /* Get report from acquisition thread */
+ integrate_thread_report(ev[i].data.u32);
+ break;
+
+ default:
+ ALOGW("Unexpected event source!\n");
+ break;
}
- goto return_first_available_sensor_report;
+ goto return_available_sensor_reports;
+}
+
+
+static void tentative_switch_trigger (int s)
+{
+ /*
+ * Under certain situations it may be beneficial to use an alternate
+ * trigger:
+ *
+ * - for applications using the accelerometer with high sampling rates,
+ * prefer the continuous trigger over the any-motion one, to avoid
+ * jumps related to motion thresholds
+ */
+
+ if (is_fast_accelerometer(s) &&
+ !(sensor_info[s].quirks & QUIRK_TERSE_DRIVER) &&
+ sensor_info[s].selected_trigger ==
+ sensor_info[s].motion_trigger_name)
+ setup_trigger(s, sensor_info[s].init_trigger_name);
}
int dev_num = sensor_info[s].dev_num;
int i = sensor_info[s].catalog_index;
const char *prefix = sensor_catalog[i].tag;
- int new_sampling_rate; /* Granted sampling rate after arbitration */
- int cur_sampling_rate; /* Currently used sampling rate */
- int req_sampling_rate; /* Requested ; may be different from granted */
+ float new_sampling_rate; /* Granted sampling rate after arbitration */
+ float cur_sampling_rate; /* Currently used sampling rate */
int per_sensor_sampling_rate;
int per_device_sampling_rate;
- int max_supported_rate = 0;
+ int32_t min_delay_us = sensor_desc[s].minDelay;
+ max_delay_t max_delay_us = sensor_desc[s].maxDelay;
+ float min_supported_rate = max_delay_us ? (1000000.0 / max_delay_us) : 1;
+ float max_supported_rate =
+ (min_delay_us && min_delay_us != -1) ? (1000000.0 / min_delay_us) : 0;
char freqs_buf[100];
char* cursor;
int n;
+ float sr;
- if (!ns) {
- ALOGE("Rejecting zero delay request on sensor %d\n", s);
+ if (ns <= 0) {
+ ALOGE("Rejecting non-positive delay request on sensor %d, required delay: %lld\n", s, ns);
return -EINVAL;
}
- new_sampling_rate = req_sampling_rate = (int) (1000000000L/ns);
+ new_sampling_rate = 1000000000LL/ns;
+
+ ALOGV("Entering set delay S%d (%s): old rate(%f), new rate(%f)\n",
+ s, sensor_info[s].friendly_name, sensor_info[s].sampling_rate,
+ new_sampling_rate);
+
+ /*
+ * Artificially limit ourselves to 1 Hz or higher. This is mostly to
+ * avoid setting up the stage for divisions by zero.
+ */
+ if (new_sampling_rate < min_supported_rate)
+ new_sampling_rate = min_supported_rate;
- if (!new_sampling_rate) {
- ALOGI("Sub-HZ sampling rate requested on on sensor %d\n", s);
- new_sampling_rate = 1;
+ if (max_supported_rate &&
+ new_sampling_rate > max_supported_rate) {
+ new_sampling_rate = max_supported_rate;
}
sensor_info[s].sampling_rate = new_sampling_rate;
- /* If we're dealing with a poll-mode sensor, release poll and return */
- if (!sensor_info[s].num_channels)
- goto exit;
+ /* If we're dealing with a poll-mode sensor */
+ if (!sensor_info[s].num_channels) {
+ /* Interrupt current sleep so the new sampling gets used */
+ pthread_cond_signal(&thread_release_cond[s]);
+ return 0;
+ }
sprintf(sysfs_path, SENSOR_SAMPLING_PATH, dev_num, prefix);
- if (sysfs_read_int(sysfs_path, &cur_sampling_rate) != -1) {
+ if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1) {
per_sensor_sampling_rate = 1;
per_device_sampling_rate = 0;
} else {
sprintf(sysfs_path, DEVICE_SAMPLING_PATH, dev_num);
- if (sysfs_read_int(sysfs_path, &cur_sampling_rate) != -1)
+ if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1)
per_device_sampling_rate = 1;
else
per_device_sampling_rate = 0;
for (n=0; n<sensor_count; n++)
if (n != s && sensor_info[n].dev_num == dev_num &&
sensor_info[n].num_channels &&
- sensor_info[n].enable_count &&
+ sensor_info[n].enabled &&
sensor_info[n].sampling_rate > new_sampling_rate)
new_sampling_rate= sensor_info[n].sampling_rate;
/* While we're not at the end of the string */
while (*cursor && cursor[0]) {
- /* Decode a single integer value */
- n = atoi(cursor);
-
- /* Cap sampling rate to CAP_SENSOR_MAX_FREQUENCY*/
- if(n > CAP_SENSOR_MAX_FREQUENCY)
- break;
-
- if (n > max_supported_rate)
- max_supported_rate = n;
+ /* Decode a single value */
+ sr = strtod(cursor, NULL);
/* If this matches the selected rate, we're happy */
- if (new_sampling_rate == n)
+ if (new_sampling_rate == sr)
break;
/*
* assumption that rates are sorted by increasing value
* in the allowed frequencies string.
*/
- if (n > new_sampling_rate) {
- ALOGI(
- "Increasing sampling rate on sensor %d from %d to %d\n",
- s, req_sampling_rate, n);
-
- new_sampling_rate = n;
+ if (sr > new_sampling_rate) {
+ new_sampling_rate = sr;
break;
}
}
}
-
if (max_supported_rate &&
new_sampling_rate > max_supported_rate) {
new_sampling_rate = max_supported_rate;
- ALOGI( "Can't support %d sampling rate, lowering to %d\n",
- req_sampling_rate, new_sampling_rate);
}
-
/* If the desired rate is already active we're all set */
if (new_sampling_rate == cur_sampling_rate)
return 0;
- ALOGI("Sensor %d sampling rate switched to %d\n", s, new_sampling_rate);
+ ALOGI("Sensor %d sampling rate set to %g\n", s, new_sampling_rate);
if (trig_sensors_per_dev[dev_num])
enable_buffer(dev_num, 0);
- sysfs_write_int(sysfs_path, new_sampling_rate);
+ sysfs_write_float(sysfs_path, new_sampling_rate);
+
+ /* Check if it makes sense to use an alternate trigger */
+ tentative_switch_trigger(s);
if (trig_sensors_per_dev[dev_num])
enable_buffer(dev_num, 1);
-exit:
- /* Release the polling loop so an updated timeout value gets used */
- write(poll_socket_pair[1], "", 1);
-
return 0;
}
+int sensor_flush (int s)
+{
+ /* If one shot or not enabled return -EINVAL */
+ if (sensor_desc[s].flags & SENSOR_FLAG_ONE_SHOT_MODE ||
+ sensor_info[s].enabled == 0)
+ return -EINVAL;
+ sensor_info[s].meta_data_pending++;
+ return 0;
+}
int allocate_control_data (void)
{
int i;
- struct epoll_event ev = {0};
for (i=0; i<MAX_DEVICES; i++)
device_fd[i] = -1;
return -1;
}
- /* Create and add "unblocking" fd to the set of watched fds */
-
- if (socketpair(AF_UNIX, SOCK_STREAM, 0, poll_socket_pair) == -1) {
- ALOGE("Can't create socket pair for iio sensors!\n");
- close(poll_fd);
- return -1;
- }
-
- ev.events = EPOLLIN;
- ev.data.u32 = INVALID_DEV_NUM;
-
- epoll_ctl(poll_fd, EPOLL_CTL_ADD, poll_socket_pair[0], &ev);
-
return poll_fd;
}