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sensors.h documentation change.

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i) on-change sensors should set maxDelay.
  ii) Drivers should hold a wake_lock till poll() is called
  the next time when delivering events from wake-up sensors.

Change-Id: I4b137843d5c857f04601618548306a710fbfbe5c
This commit is contained in:
Aravind Akella
2014-09-04 15:36:31 -07:00
parent 02516c78f3
commit 110d2f2713
1 changed files with 13 additions and 8 deletions
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21
include/hardware/sensors.h
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@@ -98,7 +98,12 @@ enum {
*/ */
enum { enum {
/* /*
* Whether this sensor wakes up the AP from suspend mode when data is available. * Whether this sensor wakes up the AP from suspend mode when data is available. Whenever
* sensor events are delivered from a wake_up sensor, the driver needs to hold a wake_lock till
* the events are read by the SensorService i.e till sensors_poll_device_t.poll() is called the
* next time. Once poll is called again it means events have been read by the SensorService, the
* driver can safely release the wake_lock. SensorService will continue to hold a wake_lock till
* the app actually reads the events.
*/ */
SENSOR_FLAG_WAKE_UP = 1U << 0, SENSOR_FLAG_WAKE_UP = 1U << 0,
/* /*
@@ -863,15 +868,15 @@ struct sensor_t {
*/ */
const char* requiredPermission; const char* requiredPermission;
/* This value is defined only for continuous mode sensors. It is the delay between two /* This value is defined only for continuous mode and on-change sensors. It is the delay between
* sensor events corresponding to the lowest frequency that this sensor supports. When * two sensor events corresponding to the lowest frequency that this sensor supports. When lower
* lower frequencies are requested through batch()/setDelay() the events will be generated * frequencies are requested through batch()/setDelay() the events will be generated at this
* at this frequency instead. It can be used by the framework or applications to estimate * frequency instead. It can be used by the framework or applications to estimate when the batch
* when the batch FIFO may be full. * FIFO may be full.
* *
* NOTE: 1) period_ns is in nanoseconds where as maxDelay/minDelay are in microseconds. * NOTE: 1) period_ns is in nanoseconds where as maxDelay/minDelay are in microseconds.
* continuous: maximum sampling period allowed in microseconds. * continuous, on-change: maximum sampling period allowed in microseconds.
* on-change, one-shot, special : 0 * one-shot, special : 0
* 2) maxDelay should always fit within a 32 bit signed integer. It is declared as 64 bit * 2) maxDelay should always fit within a 32 bit signed integer. It is declared as 64 bit
* on 64 bit architectures only for binary compatibility reasons. * on 64 bit architectures only for binary compatibility reasons.
* Availability: SENSORS_DEVICE_API_VERSION_1_3 * Availability: SENSORS_DEVICE_API_VERSION_1_3