content/browser/device_sensors/ambient_light_mac.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file is based on http://osxbook.com/book/bonus/chapter10/light/
   6
   7 #include "content/browser/device_sensors/ambient_light_mac.h"
   8
   9 #include "base/mac/scoped_cftyperef.h"
  10 #include "base/mac/scoped_ioobject.h"
  11
  12 namespace content {
  13
  14 namespace {
  15 enum LmuFunctionIndex {
  16   kGetSensorReadingID = 0,  // getSensorReading(int *, int *)
  17   kGetLEDBrightnessID = 1,  // getLEDBrightness(int, int *)
  18   kSetLEDBrightnessID = 2,  // setLEDBrightness(int, int, int *)
  19   kSetLEDFadeID = 3,        // setLEDFade(int, int, int, int *)
  20 };
  21 }  // namespace
  22
  23 // static
  24 scoped_ptr<AmbientLightSensor> AmbientLightSensor::Create() {
  25   scoped_ptr<AmbientLightSensor> light_sensor(new AmbientLightSensor);
  26   return light_sensor->Init() ? light_sensor.Pass() : nullptr;
  27 }
  28
  29 AmbientLightSensor::~AmbientLightSensor() {
  30   if (!io_connection_)
  31     IOServiceClose(io_connection_);
  32 }
  33
  34 AmbientLightSensor::AmbientLightSensor() : io_connection_(IO_OBJECT_NULL) {
  35 }
  36
  37 bool AmbientLightSensor::Init() {
  38   // Tested and verified by riju that the following call works on -
  39   // MacBookPro9,1 : Macbook Pro 15" (Mid 2012 model).
  40   // MacBookPro10,2 : Macbook Pro 13" (Retina Display, Early 2013 model).
  41   // MacBookPro10,1 : Macbook Pro 15" (Retina Display, Early 2013 model).
  42   // MacBookAir6,2 : Macbook Air 13" (Mid 2013 model).
  43   // Testing plans : Please download the code and follow the comments :-
  44   // https://gist.github.com/riju/74af8c81a665e412d122/
  45   // and add an entry here about the model and the status returned by the code.
  46
  47   // Look up a registered IOService object whose class is AppleLMUController.
  48   base::mac::ScopedIOObject<io_service_t> service_object(
  49       IOServiceGetMatchingService(kIOMasterPortDefault,
  50                                   IOServiceMatching("AppleLMUController")));
  51
  52   // Return early if the ambient light sensor is not present.
  53   if (!service_object)
  54     return false;
  55
  56   // Create a connection to the IOService object.
  57   kern_return_t kr =
  58       IOServiceOpen(service_object, mach_task_self(), 0, &io_connection_);
  59
  60   // IOServiceOpen error.
  61   if (kr != KERN_SUCCESS || io_connection_ == IO_OBJECT_NULL)
  62     return false;
  63
  64   uint64_t lux_values[2];
  65   return ReadSensorValue(lux_values);
  66 }
  67
  68 bool AmbientLightSensor::ReadSensorValue(uint64_t lux_values[2]) {
  69   uint32_t scalar_output_count = 2;
  70   kern_return_t kr = IOConnectCallMethod(
  71       io_connection_, LmuFunctionIndex::kGetSensorReadingID, nullptr, 0,
  72       nullptr, 0, lux_values, &scalar_output_count, nullptr, 0);
  73
  74   return kr == KERN_SUCCESS;
  75 }
  76
  77 }  // namespace content