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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <fcntl.h>
     18 #include <errno.h>
     19 #include <math.h>
     20 #include <poll.h>
     21 #include <unistd.h>
     22 #include <dirent.h>
     23 #include <sys/select.h>
     24 
     25 #include <linux/lightsensor.h>
     26 
     27 #include <cutils/log.h>
     28 
     29 #include "LightSensor.h"
     30 
     31 /*****************************************************************************/
     32 
     33 LightSensor::LightSensor()
     34     : SensorBase(LS_DEVICE_NAME, "lightsensor-level"),
     35       mEnabled(0),
     36       mInputReader(4),
     37       mHasPendingEvent(false)
     38 {
     39     mPendingEvent.version = sizeof(sensors_event_t);
     40     mPendingEvent.sensor = ID_L;
     41     mPendingEvent.type = SENSOR_TYPE_LIGHT;
     42     memset(mPendingEvent.data, 0, sizeof(mPendingEvent.data));
     43 
     44      open_device();
     45 
     46     int flags = 0;
     47     if (!ioctl(dev_fd, LIGHTSENSOR_IOCTL_GET_ENABLED, &flags)) {
     48         if (flags) {
     49             mEnabled = 1;
     50             setInitialState();
     51         }
     52     }
     53 
     54     if (!mEnabled) {
     55         close_device();
     56     }
     57 }
     58 
     59 LightSensor::~LightSensor() {
     60 }
     61 
     62 int LightSensor::setInitialState() {
     63     struct input_absinfo absinfo;
     64     if (!ioctl(data_fd, EVIOCGABS(EVENT_TYPE_LIGHT), &absinfo)) {
     65         mPendingEvent.light = indexToValue(absinfo.value);
     66         mHasPendingEvent = true;
     67     }
     68     return 0;
     69 }
     70 
     71 int LightSensor::enable(int32_t, int en) {
     72     int flags = en ? 1 : 0;
     73     int err = 0;
     74     if (flags != mEnabled) {
     75         if (!mEnabled) {
     76             open_device();
     77         }
     78         err = ioctl(dev_fd, LIGHTSENSOR_IOCTL_ENABLE, &flags);
     79         err = err<0 ? -errno : 0;
     80         LOGE_IF(err, "LIGHTSENSOR_IOCTL_ENABLE failed (%s)", strerror(-err));
     81         if (!err) {
     82             mEnabled = en ? 1 : 0;
     83             if (en) {
     84                 setInitialState();
     85             }
     86         }
     87         if (!mEnabled) {
     88             close_device();
     89         }
     90     }
     91     return err;
     92 }
     93 
     94 bool LightSensor::hasPendingEvents() const {
     95     return mHasPendingEvent;
     96 }
     97 
     98 int LightSensor::readEvents(sensors_event_t* data, int count)
     99 {
    100     if (count < 1)
    101         return -EINVAL;
    102 
    103     if (mHasPendingEvent) {
    104         mHasPendingEvent = false;
    105         mPendingEvent.timestamp = getTimestamp();
    106         *data = mPendingEvent;
    107         return mEnabled ? 1 : 0;
    108     }
    109 
    110     ssize_t n = mInputReader.fill(data_fd);
    111     if (n < 0)
    112         return n;
    113 
    114     int numEventReceived = 0;
    115     input_event const* event;
    116 
    117     while (count && mInputReader.readEvent(&event)) {
    118         int type = event->type;
    119         if (type == EV_ABS) {
    120             if (event->code == EVENT_TYPE_LIGHT) {
    121                 if (event->value != -1) {
    122                     // FIXME: not sure why we're getting -1 sometimes
    123                     mPendingEvent.light = indexToValue(event->value);
    124                 }
    125             }
    126         } else if (type == EV_SYN) {
    127             mPendingEvent.timestamp = timevalToNano(event->time);
    128             if (mEnabled) {
    129                 *data++ = mPendingEvent;
    130                 count--;
    131                 numEventReceived++;
    132             }
    133         } else {
    134             LOGE("LightSensor: unknown event (type=%d, code=%d)",
    135                     type, event->code);
    136         }
    137         mInputReader.next();
    138     }
    139 
    140     return numEventReceived;
    141 }
    142 
    143 float LightSensor::indexToValue(size_t index) const
    144 {
    145     static const float luxValues[8] = {
    146             10.0, 160.0, 225.0, 320.0,
    147             640.0, 1280.0, 2600.0, 10240.0
    148     };
    149 
    150     const size_t maxIndex = sizeof(luxValues)/sizeof(*luxValues) - 1;
    151     if (index > maxIndex)
    152         index = maxIndex;
    153     return luxValues[index];
    154 }
    155