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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <fcntl.h>
#include <errno.h>
#include <math.h>
#include <poll.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/select.h>
#include <cutils/log.h>
#include "LightSensor.h"
/*****************************************************************************/
/* The Crespo ADC sends 4 somewhat bogus events after enabling the sensor.
This becomes a problem if the phone is turned off in bright light
and turned back on in the dark.
To avoid this we ignore the first 4 events received after enabling the sensor.
*/
#define FIRST_GOOD_EVENT 5
LightSensor::LightSensor()
: SensorBase(NULL, "light_sensor"),
mEnabled(0),
mEventsSinceEnable(0),
mInputReader(4),
mHasPendingEvent(false)
{
mPendingEvent.version = sizeof(sensors_event_t);
mPendingEvent.sensor = ID_L;
mPendingEvent.type = SENSOR_TYPE_LIGHT;
memset(mPendingEvent.data, 0, sizeof(mPendingEvent.data));
if (data_fd) {
strcpy(input_sysfs_path, "/sys/class/input/");
strcat(input_sysfs_path, input_name);
strcat(input_sysfs_path, "/device/");
input_sysfs_path_len = strlen(input_sysfs_path);
enable(0, 1);
}
}
LightSensor::~LightSensor() {
if (mEnabled) {
enable(0, 0);
}
}
int LightSensor::setDelay(int32_t handle, int64_t ns)
{
int fd;
strcpy(&input_sysfs_path[input_sysfs_path_len], "poll_delay");
fd = open(input_sysfs_path, O_RDWR);
if (fd >= 0) {
char buf[80];
sprintf(buf, "%lld", ns);
write(fd, buf, strlen(buf)+1);
close(fd);
return 0;
}
return -1;
}
int LightSensor::enable(int32_t handle, int en)
{
int flags = en ? 1 : 0;
mEventsSinceEnable = 0;
mPreviousLight = -1;
if (flags != mEnabled) {
int fd;
strcpy(&input_sysfs_path[input_sysfs_path_len], "enable");
fd = open(input_sysfs_path, O_RDWR);
if (fd >= 0) {
char buf[2];
int err;
buf[1] = 0;
if (flags) {
buf[0] = '1';
} else {
buf[0] = '0';
}
err = write(fd, buf, sizeof(buf));
close(fd);
mEnabled = flags;
return 0;
}
return -1;
}
return 0;
}
bool LightSensor::hasPendingEvents() const {
return mHasPendingEvent;
}
int LightSensor::readEvents(sensors_event_t* data, int count)
{
if (count < 1)
return -EINVAL;
if (mHasPendingEvent) {
mHasPendingEvent = false;
mPendingEvent.timestamp = getTimestamp();
*data = mPendingEvent;
return mEnabled ? 1 : 0;
}
ssize_t n = mInputReader.fill(data_fd);
if (n < 0)
return n;
int numEventReceived = 0;
input_event const* event;
while (count && mInputReader.readEvent(&event)) {
int type = event->type;
if (type == EV_ABS) {
if (event->code == EVENT_TYPE_LIGHT) {
mPendingEvent.light = indexToValue(event->value);
if (mEventsSinceEnable < FIRST_GOOD_EVENT)
mEventsSinceEnable++;
}
} else if (type == EV_SYN) {
mPendingEvent.timestamp = timevalToNano(event->time);
if (mEnabled && (mPendingEvent.light != mPreviousLight) &&
mEventsSinceEnable >= FIRST_GOOD_EVENT) {
*data++ = mPendingEvent;
count--;
numEventReceived++;
mPreviousLight = mPendingEvent.light;
}
} else {
LOGE("LightSensor: unknown event (type=%d, code=%d)",
type, event->code);
}
mInputReader.next();
}
return numEventReceived;
}
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[] = {
{ 150, 10.0 }, /* from 0 - 150 adc, we map to 10.0 lux */
{ 800, 160.0 }, /* from 151 - 800 adc, we map to 160.0 lux */
{ 900, 225.0 }, /* from 801 - 900 adc, we map to 225.0 lux */
{ 1000, 320.0 }, /* from 901 - 1000 adc, we map to 320.0 lux */
{ 1200, 640.0 }, /* from 1001 - 1200 adc, we map to 640.0 lux */
{ 1400, 1280.0 }, /* from 1201 - 1400 adc, we map to 1280.0 lux */
{ 1600, 2600.0 }, /* from 1401 - 1600 adc, we map to 2600.0 lux */
{ 4095, 10240.0 }, /* from 1601 - 4095 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;
}
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