2 * Copyright (C) 2014 Intel Corporation.
9 #include <hardware/sensors.h>
11 #include "enumeration.h"
14 /* Currently active sensors count, per device */
15 static int poll_sensors_per_dev[MAX_DEVICES]; /* poll-mode sensors */
16 static int trig_sensors_per_dev[MAX_DEVICES]; /* trigger, event based */
18 static int device_fd[MAX_DEVICES]; /* fd on the /dev/iio:deviceX file */
20 static int poll_fd; /* epoll instance covering all enabled sensors */
22 /* Timestamp for the moment when we last exited a poll operation */
23 static int64_t last_poll_exit_ts;
25 /* Cap the time between poll operations to this, to counter runaway polls */
26 #define POLL_MIN_INTERVAL 10000 /* uS */
28 static int active_poll_sensors; /* Number of enabled poll-mode sensors */
31 static int enable_buffer(int dev_num, int enabled)
33 char sysfs_path[PATH_MAX];
35 sprintf(sysfs_path, ENABLE_PATH, dev_num);
37 /* Low level, non-multiplexed, enable/disable routine */
38 return sysfs_write_int(sysfs_path, enabled);
42 static int setup_trigger(int dev_num, const char* trigger_val)
44 char sysfs_path[PATH_MAX];
46 sprintf(sysfs_path, TRIGGER_PATH, dev_num);
48 return sysfs_write_str(sysfs_path, trigger_val);
52 static void refresh_sensor_report_maps(int dev_num)
55 * Read sysfs files from a iio device's scan_element directory, and
56 * build a couple of tables from that data. These tables will tell, for
57 * each sensor, where to gather relevant data in a device report, i.e.
58 * the structure that we read from the /dev/iio:deviceX file in order to
59 * sensor report, itself being the data that we return to Android when a
60 * sensor poll completes. The mapping should be straightforward in the
61 * case where we have a single sensor active per iio device but, this is
62 * not the general case. In general several sensors can be handled
63 * through a single iio device, and the _en, _index and _type syfs
64 * entries all concur to paint a picture of what the structure of the
75 char spec_buf[MAX_TYPE_SPEC_LEN];
76 struct datum_info_t* ch_info;
78 char sysfs_path[PATH_MAX];
82 int channel_size_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
83 int sensor_handle_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
84 int channel_number_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
88 /* For each sensor that is linked to this device */
89 for (s=0; s<sensor_count; s++) {
90 if (sensor_info[s].dev_num != dev_num)
93 i = sensor_info[s].catalog_index;
95 /* Read channel status through syfs attributes */
96 for (c=0; c<sensor_info[s].num_channels; c++) {
99 sprintf(sysfs_path, CHANNEL_PATH "%s",
100 sensor_info[s].dev_num,
101 sensor_catalog[i].channel[c].en_path);
103 n = sysfs_read_int(sysfs_path, &ch_enabled);
106 ALOGW( "Failed to read _en flag: %s\n",
111 if (!ch_enabled != 1) {
112 sensor_info[s].channel[c].size = 0;
115 /* Read _type file */
116 sprintf(sysfs_path, CHANNEL_PATH "%s",
117 sensor_info[s].dev_num,
118 sensor_catalog[i].channel[c].type_path);
120 n = sysfs_read_str(sysfs_path, spec_buf,
124 ALOGW( "Failed to read type: %s\n",
129 ch_spec = sensor_info[s].channel[c].type_spec;
131 memcpy(ch_spec, spec_buf, sizeof(spec_buf));
133 ch_info = &sensor_info[s].channel[c].type_info;
135 size = decode_type_spec(ch_spec, ch_info);
137 /* Read _index file */
138 sprintf(sysfs_path, CHANNEL_PATH "%s",
139 sensor_info[s].dev_num,
140 sensor_catalog[i].channel[c].index_path);
142 n = sysfs_read_int(sysfs_path, &ch_index);
145 ALOGW( "Failed to read index: %s\n",
150 /* Record what this index is about */
152 sensor_handle_from_index [ch_index] = s;
153 channel_number_from_index[ch_index] = c;
154 channel_size_from_index [ch_index] = size;
160 ALOGI("Found %d enabled channels for iio device %d\n", active_channels,
164 * Now that we know which channels are enabled, their sizes and their
165 * ordering, update channels offsets within device report. Note: there
166 * is a possibility that several sensors share the same index, with
167 * their data fields being isolated by masking and shifting as specified
168 * through the real bits and shift values in type attributes. This case
169 * is not currently supported. Also, the code below assumes no hole in
170 * the sequence of indices, so it is dependent on discovery of all
174 for (i=0; i<MAX_SENSORS * MAX_CHANNELS; i++) {
175 s = sensor_handle_from_index[i];
176 c = channel_number_from_index[i];
177 size = channel_size_from_index[i];
182 ALOGI("S%d C%d : offset %d, size %d, type %s\n",
183 s, c, offset, size, sensor_info[s].channel[c].type_spec);
185 sensor_info[s].channel[c].offset = offset;
186 sensor_info[s].channel[c].size = size;
193 int adjust_counters (int s, int enabled)
196 * Adjust counters based on sensor enable action. Return values are:
197 * -1 if there's an inconsistency: abort action in this case
198 * 0 if the operation was completed and we're all set
199 * 1 if we toggled the state of the sensor and there's work left
202 int dev_num = sensor_info[s].dev_num;
204 /* Refcount per sensor, in terms of enable count */
206 ALOGI("Enabling sensor %d (iio device %d: %s)\n",
207 s, dev_num, sensor_info[s].internal_name);
209 sensor_info[s].enable_count++;
211 if (sensor_info[s].enable_count != 1)
212 return 0; /* The sensor was, and remains, in use */
214 if (sensor_info[s].enable_count == 0)
215 return -1; /* Spurious disable call */
217 ALOGI("Disabling sensor %d (iio device %d)\n", s, dev_num);
219 sensor_info[s].enable_count--;
221 if (sensor_info[s].enable_count > 0)
222 return 0; /* The sensor was, and remains, in use */
224 /* Sensor disabled, clear up pending data */
226 sensor_info[s].report_pending = 0;
227 memset(sensor_info[s].report_buffer, 0, MAX_SENSOR_REPORT_SIZE);
230 /* We changed the state of a sensor - adjust per iio device counters */
232 /* If this is a regular event-driven sensor */
233 if (sensor_info[s].num_channels) {
236 trig_sensors_per_dev[dev_num]++;
238 trig_sensors_per_dev[dev_num]--;
244 active_poll_sensors++;
245 poll_sensors_per_dev[dev_num]++;
249 active_poll_sensors--;
250 poll_sensors_per_dev[dev_num]--;
255 int sensor_activate(int s, int enabled)
257 char sysfs_path[PATH_MAX];
258 char device_name[PATH_MAX];
259 char trigger_name[MAX_NAME_SIZE + 16];
261 struct epoll_event ev = {0};
264 int dev_num = sensor_info[s].dev_num;
265 int i = sensor_info[s].catalog_index;
266 int is_poll_sensor = !sensor_info[s].num_channels;
268 ret = adjust_counters(s, enabled);
270 /* If the operation was neutral in terms of state, we're done */
274 if (!is_poll_sensor) {
275 /* Changes have to be made while the buffer is turned off */
276 enable_buffer(dev_num, 0);
278 /* Configure trigger */
279 switch (trig_sensors_per_dev[dev_num]) {
281 setup_trigger(dev_num, "none");
285 sprintf(trigger_name, "%s-dev%d",
286 sensor_info[s].internal_name, dev_num);
288 setup_trigger(dev_num, trigger_name);
292 /* The trigger is already set */
297 * Turn channels associated to this sensor on or off, and update
298 * the channels maps for all sensors associated to this device.
300 for (c=0;c<sensor_info[s].num_channels; c++) {
301 sprintf(sysfs_path, CHANNEL_PATH "%s",
302 sensor_info[s].dev_num,
303 sensor_catalog[i].channel[c].en_path);
305 sysfs_write_int(sysfs_path, enabled);
308 /* If there's at least one sensor left */
309 if (trig_sensors_per_dev[dev_num]) {
310 refresh_sensor_report_maps(dev_num);
311 enable_buffer(dev_num, 1);
316 * Make sure we have a fd on the character device ; conversely, close
317 * the fd if no one is using associated sensor anymore. The assumption
318 * here is that the underlying driver will power on the relevant
319 * hardware block while someone hold a fd on the device.
321 dev_fd = device_fd[dev_num];
323 switch (poll_sensors_per_dev[dev_num] + trig_sensors_per_dev[dev_num]) {
328 * Stop watching this fd. This should be a no-op
329 * in case this fd was not in the poll set.
331 epoll_ctl(poll_fd, EPOLL_CTL_DEL, dev_fd, NULL);
334 device_fd[dev_num] = -1;
339 /* First enabled sensor on this iio device */
340 sprintf(device_name, DEV_FILE_PATH, dev_num);
341 dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
344 ALOGE("Could not open fd on %s (%s)\n",
345 device_name, strerror(errno));
349 ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
351 device_fd[dev_num] = dev_fd;
358 if (!is_poll_sensor && trig_sensors_per_dev[dev_num] == 1) {
360 /* Add this iio device fd to the set of watched fds */
362 ev.data.u32 = dev_num;
364 ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
367 ALOGE("Failed adding %d to poll set (%s)\n", dev_fd,
372 /* Note: poll-mode fds are not readable */
379 static int integrate_device_report(int dev_num)
383 unsigned char buf[MAX_SENSOR_REPORT_SIZE * MAX_SENSORS] = { 0 };
386 unsigned char *target;
387 unsigned char *source;
389 int expected_size = 0;
391 if (dev_num < 0 || dev_num >= MAX_DEVICES)
394 /* There's an incoming report on the specified fd */
396 for (s=0; s<MAX_SENSORS; s++)
397 if (sensor_info[s].enable_count &&
398 sensor_info[s].dev_num == dev_num)
399 for (c=0; c<sensor_info[s].num_channels; c++)
400 expected_size += sensor_info[s].channel[c].size;
402 if (expected_size == 0)
405 len = read(device_fd[dev_num], buf, expected_size);
408 ALOGE("Could not read report from iio device %d (%s)\n",
409 dev_num, strerror(errno));
413 ALOGV("Read %d bytes from iio device %d\n", len, dev_num);
417 for (s=0; s<MAX_SENSORS; s++)
418 if (sensor_info[s].enable_count &&
419 sensor_info[s].dev_num == dev_num) {
422 /* Copy data from device to sensor report buffer */
423 for (c=0; c<sensor_info[s].num_channels; c++) {
425 target = sensor_info[s].report_buffer +
428 source = buf + sensor_info[s].channel[c].offset;
430 size = sensor_info[s].channel[c].size;
432 memcpy(target, source, size);
437 ALOGV("Sensor %d report available (%d bytes)\n",
440 sensor_info[s].report_pending = 1;
447 static float acquire_immediate_value(int s, int c)
449 char sysfs_path[PATH_MAX];
452 int dev_num = sensor_info[s].dev_num;
453 int i = sensor_info[s].catalog_index;
454 const char* raw_path = sensor_catalog[i].channel[c].raw_path;
455 const char* input_path = sensor_catalog[i].channel[c].input_path;
456 float scale = sensor_info[s].scale;
457 float offset = sensor_info[s].offset;
459 /* Acquire a sample value for sensor s / channel c through sysfs */
462 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
463 ret = sysfs_read_float(sysfs_path, &val);
473 sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
474 ret = sysfs_read_float(sysfs_path, &val);
483 static void propagate_sensor_report(int s, struct sensors_event_t* data)
485 /* There's a sensor report pending for this sensor ; transmit it */
487 int catalog_index = sensor_info[s].catalog_index;
488 int sensor_type = sensor_catalog[catalog_index].type;
491 unsigned char* current_sample;
493 struct datum_info_t* sample_type;
497 memset(data, 0, sizeof(sensors_event_t));
499 data->version = sizeof(sensors_event_t);
501 data->type = sensor_type;
502 data->timestamp = get_timestamp();
504 switch (sensor_type) {
505 case SENSOR_TYPE_ACCELEROMETER: /* m/s^2 */
506 case SENSOR_TYPE_MAGNETIC_FIELD: /* micro-tesla */
507 case SENSOR_TYPE_ORIENTATION: /* degrees */
508 case SENSOR_TYPE_GYROSCOPE: /* radians/s */
512 case SENSOR_TYPE_LIGHT: /* SI lux units */
513 case SENSOR_TYPE_AMBIENT_TEMPERATURE: /* °C */
514 case SENSOR_TYPE_TEMPERATURE: /* °C */
515 case SENSOR_TYPE_PROXIMITY: /* centimeters */
516 case SENSOR_TYPE_PRESSURE: /* hecto-pascal */
517 case SENSOR_TYPE_RELATIVE_HUMIDITY: /* percent */
521 case SENSOR_TYPE_ROTATION_VECTOR:
525 case SENSOR_TYPE_DEVICE_PRIVATE_BASE: /* hidden for now */
530 ALOGE("Unknown sensor type!\n");
535 ALOGV("Sample on sensor %d (type %d):\n", s, sensor_type);
537 /* If we're dealing with a poll-mode sensor */
538 if (!sensor_info[s].num_channels) {
540 /* Read values through sysfs rather than from a report buffer */
541 for (c=0; c<num_fields; c++) {
542 val = acquire_immediate_value(s, c);
544 data->data[c] = transform_sample(sensor_type, c, val);
546 ALOGV("\tfield %d: %f\n", c, data->data[c]);
551 /* Convert the data into the expected Android-level format */
553 current_sample = sensor_info[s].report_buffer;
555 for (c=0; c<num_fields; c++) {
556 sample_size = sensor_info[s].channel[c].size;
557 sample_type = &sensor_info[s].channel[c].type_info;
559 s64 = sample_as_int64(current_sample, sample_type);
561 val = (sensor_info[s].offset + s64) * sensor_info[s].scale;
563 data->data[c] = transform_sample(sensor_type, c, val);
565 ALOGV("\tfield %d: %f\n", c, data->data[c]);
566 current_sample += sample_size;
571 static int get_poll_time (void)
573 if (!active_poll_sensors)
574 return -1; /* Infinite wait */
576 return 100; /* ms ... this needs to be dynamic */
580 int sensor_poll(struct sensors_event_t* data, int count)
586 struct epoll_event ev[MAX_DEVICES];
588 /* Get one or more events from our collection of sensors */
590 return_first_available_sensor_report:
592 /* If there's at least one available report */
593 for (s=0; s<sensor_count; s++)
594 if (sensor_info[s].report_pending) {
597 propagate_sensor_report(s, data);
598 sensor_info[s].report_pending = 0;
599 ALOGV("Report on sensor %d\n", s);
603 /* Keep a minimum time interval between poll operations */
604 delta = (get_timestamp() - last_poll_exit_ts)/1000;
606 if (delta > 0 && delta < POLL_MIN_INTERVAL)
607 usleep(POLL_MIN_INTERVAL - delta);
609 ALOGV("Awaiting sensor data\n");
611 nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_time());
613 last_poll_exit_ts = get_timestamp();
615 ALOGV("%d fds signalled\n", nfds);
617 /* For each of the devices for which a report is available */
618 for (i=0; i<nfds; i++)
619 if (ev[i].events == EPOLLIN)
621 integrate_device_report(ev[i].data.u32);
623 /* It's a good time to invalidate poll-mode sensor values */
624 for (s=0; s<sensor_count; s++)
625 if (!sensor_info[s].num_channels && sensor_info[s].enable_count)
626 sensor_info[s].report_pending = 1;
628 goto return_first_available_sensor_report;
632 int sensor_set_delay(int handle, int64_t ns)
634 /* Set the rate at which a specific sensor should report events */
635 /* Continuous reports: accelerometer, gyroscope */
636 /* On change with minimum delay between events: ALS, proximity */
637 /* See sensors.h for indication on sensor trigger modes */
642 int allocate_control_data (void)
646 for (i=0; i<MAX_DEVICES; i++)
649 poll_fd = epoll_create(MAX_DEVICES);
652 ALOGE("Can't create epoll instance for iio sensors!\n");
659 void delete_control_data (void)