Added SensorManager.getMinDelay()

Exposed the new "min delay" sensor property through native and
java sensor apis. This allows the caller to know what is the
maximum rate at which a sensor can return events, or, if a sensor
works in "update" mode (events returned only when the value changes).

Also augmented SensorManager.regusterSensorEvent() so that it can
accept a value in microsecond in addition to the 4 constants already
defined.

Change-Id: If425e9979892666df8c989d7de3c362230fa19e0

10 files changed, 61 insertions, 11 deletions

diff --git a/api/current.xml b/api/current.xml
index f1a383fedc5e..9de160a8a9d5 100644
--- a/api/current.xml
+++ b/api/current.xml
@@ -77549,6 +77549,17 @@
  visibility="public"
 >
 </method>
+<method name="getMinDelay"
+ return="int"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="false"
+ final="false"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</method>
 <method name="getName"
  return="java.lang.String"
  abstract="false"
diff --git a/core/java/android/hardware/Sensor.java b/core/java/android/hardware/Sensor.java
index 3490ac0e7d77..b49a409ceef8 100644
--- a/core/java/android/hardware/Sensor.java
+++ b/core/java/android/hardware/Sensor.java
@@ -92,6 +92,7 @@ public class Sensor {
     private float   mMaxRange;
     private float   mResolution;
     private float   mPower;
+    private int     mMinDelay;
     private int     mLegacyType;
 
 
@@ -147,6 +148,15 @@ public class Sensor {
         return mPower;
     }
 
+    /**
+     * @return the minimum delay allowed between two events in microsecond
+     * or zero if this sensor only returns a value when the data it's measuring
+     * changes.
+     */
+    public int getMinDelay() {
+        return mMinDelay;
+    }
+
     int getHandle() {
         return mHandle;
     }
diff --git a/core/java/android/hardware/SensorManager.java b/core/java/android/hardware/SensorManager.java
index e6750e677705..5cc8d5d229c9 100644
--- a/core/java/android/hardware/SensorManager.java
+++ b/core/java/android/hardware/SensorManager.java
@@ -935,7 +935,8 @@ public class SensorManager
      *        received faster or slower than the specified rate. Usually events
      *        are received faster. The value must be one of
      *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
-     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
+     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}
+     *        or, the desired delay between events in microsecond.
      *
      * @return <code>true</code> if the sensor is supported and successfully
      *         enabled.
@@ -967,6 +968,7 @@ public class SensorManager
      *        are received faster. The value must be one of
      *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
      *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
+     *        or, the desired delay between events in microsecond.
      *
      * @param handler
      *        The {@link android.os.Handler Handler} the
@@ -992,16 +994,17 @@ public class SensorManager
                 delay = 0;
                 break;
             case SENSOR_DELAY_GAME:
-                delay = 20;
+                delay = 20000;
                 break;
             case SENSOR_DELAY_UI:
-                delay = 60;
+                delay = 60000;
                 break;
             case SENSOR_DELAY_NORMAL:
-                delay = 200;
+                delay = 200000;
                 break;
             default:
-                return false;
+                delay = rate;
+                break;
         }
 
         synchronized (sListeners) {
diff --git a/core/jni/android_hardware_SensorManager.cpp b/core/jni/android_hardware_SensorManager.cpp
index 7b2341813099..e29495cf0543 100644
--- a/core/jni/android_hardware_SensorManager.cpp
+++ b/core/jni/android_hardware_SensorManager.cpp
@@ -38,6 +38,7 @@ struct SensorOffsets
     jfieldID    range;
     jfieldID    resolution;
     jfieldID    power;
+    jfieldID    minDelay;
 } gSensorOffsets;
 
 /*
@@ -74,6 +75,7 @@ sensors_module_get_next_sensor(JNIEnv *env, jobject clazz, jobject sensor, jint
     env->SetFloatField(sensor, sensorOffsets.range,      list->getMaxValue());
     env->SetFloatField(sensor, sensorOffsets.resolution, list->getResolution());
     env->SetFloatField(sensor, sensorOffsets.power,      list->getPowerUsage());
+    env->SetIntField(sensor, sensorOffsets.minDelay,     list->getMinDelay());
     
     next++;
     return next<count ? next : 0;
@@ -154,6 +156,7 @@ nativeClassInit (JNIEnv *_env, jclass _this)
     sensorOffsets.range       = _env->GetFieldID(sensorClass, "mMaxRange",  "F");
     sensorOffsets.resolution  = _env->GetFieldID(sensorClass, "mResolution","F");
     sensorOffsets.power       = _env->GetFieldID(sensorClass, "mPower",     "F");
+    sensorOffsets.minDelay    = _env->GetFieldID(sensorClass, "mMinDelay",  "I");
 }
 
 static JNINativeMethod gMethods[] = {
diff --git a/include/gui/Sensor.h b/include/gui/Sensor.h
index e696d6386819..2de07b1325a9 100644
--- a/include/gui/Sensor.h
+++ b/include/gui/Sensor.h
@@ -63,6 +63,7 @@ public:
     float getMaxValue() const;
     float getResolution() const;
     float getPowerUsage() const;
+    int32_t getMinDelay() const;
 
     // Flattenable interface
     virtual size_t getFlattenedSize() const;
@@ -81,6 +82,7 @@ private:
     float   mMaxValue;
     float   mResolution;
     float   mPower;
+    int32_t mMinDelay;
 };
 
 // ----------------------------------------------------------------------------
diff --git a/include/gui/SensorEventQueue.h b/include/gui/SensorEventQueue.h
index ad36dacea629..6581ae3092f6 100644
--- a/include/gui/SensorEventQueue.h
+++ b/include/gui/SensorEventQueue.h
@@ -65,7 +65,7 @@ public:
     status_t setEventRate(Sensor const* sensor, nsecs_t ns) const;
 
     // these are here only to support SensorManager.java
-    status_t enableSensor(int32_t handle, int32_t ms) const;
+    status_t enableSensor(int32_t handle, int32_t us) const;
     status_t disableSensor(int32_t handle) const;
 
 private:
diff --git a/libs/gui/Sensor.cpp b/libs/gui/Sensor.cpp
index cb85df9bb04d..b1f37ffed2a8 100644
--- a/libs/gui/Sensor.cpp
+++ b/libs/gui/Sensor.cpp
@@ -32,7 +32,7 @@ namespace android {
 Sensor::Sensor()
     : mHandle(0), mType(0),
       mMinValue(0), mMaxValue(0), mResolution(0),
-      mPower(0)
+      mPower(0), mMinDelay(0)
 {
 }
 
@@ -46,6 +46,7 @@ Sensor::Sensor(struct sensor_t const* hwSensor)
     mMaxValue = hwSensor->maxRange;     // FIXME: maxValue
     mResolution = hwSensor->resolution;
     mPower = hwSensor->power;
+    mMinDelay = hwSensor->minDelay;
 }
 
 Sensor::~Sensor()
@@ -84,12 +85,17 @@ float Sensor::getPowerUsage() const {
     return mPower;
 }
 
+int32_t Sensor::getMinDelay() const {
+    return mMinDelay;
+}
+
 size_t Sensor::getFlattenedSize() const
 {
     return  sizeof(int32_t) + ((mName.length() + 3) & ~3) +
             sizeof(int32_t) + ((mVendor.length() + 3) & ~3) +
             sizeof(int32_t) * 2 +
-            sizeof(float) * 4;
+            sizeof(float) * 4 +
+            sizeof(int32_t);
 }
 
 size_t Sensor::getFdCount() const
@@ -132,6 +138,7 @@ status_t Sensor::flatten(void* buffer, size_t size,
     offset += write(buffer, offset, mMaxValue);
     offset += write(buffer, offset, mResolution);
     offset += write(buffer, offset, mPower);
+    offset += write(buffer, offset, mMinDelay);
 
     return NO_ERROR;
 }
@@ -169,6 +176,7 @@ status_t Sensor::unflatten(void const* buffer, size_t size,
     offset += read(buffer, offset, &mMaxValue);
     offset += read(buffer, offset, &mResolution);
     offset += read(buffer, offset, &mPower);
+    offset += read(buffer, offset, &mMinDelay);
 
     return NO_ERROR;
 }
diff --git a/libs/gui/SensorEventQueue.cpp b/libs/gui/SensorEventQueue.cpp
index 4b468424912b..3396f25e714a 100644
--- a/libs/gui/SensorEventQueue.cpp
+++ b/libs/gui/SensorEventQueue.cpp
@@ -114,10 +114,10 @@ status_t SensorEventQueue::disableSensor(Sensor const* sensor) const {
     return mSensorEventConnection->enableDisable(sensor->getHandle(), false);
 }
 
-status_t SensorEventQueue::enableSensor(int32_t handle, int32_t ms) const {
+status_t SensorEventQueue::enableSensor(int32_t handle, int32_t us) const {
     status_t err = mSensorEventConnection->enableDisable(handle, true);
     if (err == NO_ERROR) {
-        mSensorEventConnection->setEventRate(handle, ms2ns(ms));
+        mSensorEventConnection->setEventRate(handle, us2ns(us));
     }
     return err;
 }
diff --git a/native/android/sensor.cpp b/native/android/sensor.cpp
index e1fc4e7bc9ac..db534e09dab8 100644
--- a/native/android/sensor.cpp
+++ b/native/android/sensor.cpp
@@ -149,3 +149,7 @@ float ASensor_getResolution(ASensor const* sensor)
     return static_cast<Sensor const*>(sensor)->getResolution();
 }
 
+int ASensor_getMinDelay(ASensor const* sensor)
+{
+    return static_cast<Sensor const*>(sensor)->getMinDelay();
+}
diff --git a/native/include/android/sensor.h b/native/include/android/sensor.h
index 00d95d8e64fc..b4ce0242682d 100644
--- a/native/include/android/sensor.h
+++ b/native/include/android/sensor.h
@@ -121,6 +121,7 @@ typedef struct ASensorEvent {
         float           temperature;
         float           distance;
         float           light;
+        float           pressure;
     };
     int32_t reserved1[4];
 } ASensorEvent;
@@ -188,7 +189,8 @@ int ASensorEventQueue_disableSensor(ASensorEventQueue* queue, ASensor const* sen
 /*
  * Sets the delivery rate of events in microseconds for the given sensor.
  * Note that this is a hint only, generally event will arrive at a higher
- * rate.
+ * rate. It is an error to set a rate inferior to the value returned by
+ * ASensor_getMinDelay().
  * Returns a negative error code on failure.
  */
 int ASensorEventQueue_setEventRate(ASensorEventQueue* queue, ASensor const* sensor, int32_t usec);
@@ -239,6 +241,13 @@ int ASensor_getType(ASensor const* sensor);
  */
 float ASensor_getResolution(ASensor const* sensor);
 
+/*
+ * Returns the minimum delay allowed between events in microseconds.
+ * A value of zero means that this sensor doesn't report events at a
+ * constant rate, but rather only when a new data is available.
+ */
+int ASensor_getMinDelay(ASensor const* sensor);
+
 
 #ifdef __cplusplus
 };