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authorArve Hjønnevåg <arve@android.com>2011-10-25 17:54:35 -0700
committerArve Hjønnevåg <arve@android.com>2011-11-01 20:09:10 -0700
commitdbc6da918cb77f4d96df97fd8f7c326f2783699a (patch)
tree72b193222661dd1e514967be0b8ec9f71ebe21ac /libsensors
parentde47e22bfed40584093220c7e35351e0340864fe (diff)
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sensors: Return a calculated lux value instead using the current 8 entry table
The light sensor now uses the lux to current formula in the datasheet, I = 10 * log(Ev) uA, and multiplies the result by 4 as an attempt to correct for the glass in front of the sensor. Also update the config_autoBrightnessLevels table so the auto brightness change occurs at the same adc values as before (or close for 7.2 lux). Change-Id: I121ce0f23dca093c9607ac9447b9263f48507a09
Diffstat (limited to 'libsensors')
-rw-r--r--libsensors/LightSensor.cpp43
-rw-r--r--libsensors/LightSensor.h3
-rw-r--r--libsensors/sensors.cpp2
3 files changed, 8 insertions, 40 deletions
diff --git a/libsensors/LightSensor.cpp b/libsensors/LightSensor.cpp
index 15ae4e2..29b222b 100644
--- a/libsensors/LightSensor.cpp
+++ b/libsensors/LightSensor.cpp
@@ -31,46 +31,17 @@ LightSensor::LightSensor()
{
mPendingEvent.sensor = ID_L;
mPendingEvent.type = SENSOR_TYPE_LIGHT;
- mPreviousLight = -1;
-}
-
-int LightSensor::handleEnable(int en) {
- mPreviousLight = -1;
- return 0;
}
bool LightSensor::handleEvent(input_event const *event) {
if (event->value == -1) {
return false;
}
- mPendingEvent.light = indexToValue(event->value);
- if (mPendingEvent.light != mPreviousLight) {
- mPreviousLight = mPendingEvent.light;
- return true;
- }
- return false;
-}
-
-float LightSensor::indexToValue(size_t index) const {
- /* Driver gives a rolling average adc value. We convert it lux levels. */
- static const struct adcToLux {
- size_t adc_value;
- float lux_value;
- } adcToLux[] = {
- { 50, 10.0 }, /* from 0 - 50 adc, we map to 10.0 lux */
- { 280, 160.0 }, /* from 51 - 280 adc, we map to 160.0 lux */
- { 320, 225.0 }, /* from 281 - 320 adc, we map to 225.0 lux */
- { 350, 320.0 }, /* from 321 - 350 adc, we map to 320.0 lux */
- { 400, 640.0 }, /* from 351 - 400 adc, we map to 640.0 lux */
- { 520, 1280.0 }, /* from 401 - 520 adc, we map to 1280.0 lux */
- { 590, 2600.0 }, /* from 521 - 590 adc, we map to 2600.0 lux */
- { 1024, 10240.0 }, /* from 591 - 1024 adc, we map to 10240.0 lux */
- };
- size_t i;
- for (i = 0; i < ARRAY_SIZE(adcToLux); i++) {
- if (index <= adcToLux[i].adc_value) {
- return adcToLux[i].lux_value;
- }
- }
- return adcToLux[ARRAY_SIZE(adcToLux)-1].lux_value;
+ // Convert adc value to lux assuming:
+ // I = 10 * log(Ev) uA
+ // R = 24kOhm
+ // Max adc value 1023 = 1.25V
+ // 1/4 of light reaches sensor
+ mPendingEvent.light = powf(10, event->value * (125.0f / 1023.0f / 24.0f)) * 4;
+ return true;
}
diff --git a/libsensors/LightSensor.h b/libsensors/LightSensor.h
index ed3b435..f5f8af0 100644
--- a/libsensors/LightSensor.h
+++ b/libsensors/LightSensor.h
@@ -32,10 +32,7 @@ struct input_event;
class LightSensor:public SamsungSensorBase {
- float mPreviousLight;
- virtual int handleEnable(int en);
virtual bool handleEvent(input_event const * event);
- float indexToValue(size_t index) const;
public:
LightSensor();
};
diff --git a/libsensors/sensors.cpp b/libsensors/sensors.cpp
index 450dbd5..a884ce7 100644
--- a/libsensors/sensors.cpp
+++ b/libsensors/sensors.cpp
@@ -80,7 +80,7 @@ static struct sensor_t sSensorList[LOCAL_SENSORS + MPLSensor::numSensors] = {
{ "GP2A Light sensor",
"Sharp",
1, SENSORS_LIGHT_HANDLE,
- SENSOR_TYPE_LIGHT, 3000.0f, 1.0f, 0.75f, 0, { } },
+ SENSOR_TYPE_LIGHT, powf(10, 125.0f/ 24.0f) * 4, 1.0f, 0.75f, 0, { } },
{ "GP2A Proximity sensor",
"Sharp",
1, SENSORS_PROXIMITY_HANDLE,