diff options
Diffstat (limited to 'libsensors/LightSensor.cpp')
-rw-r--r-- | libsensors/LightSensor.cpp | 43 |
1 files changed, 7 insertions, 36 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; } |