chromeos/accelerometer/accelerometer_reader.cc - platform/external/chromium_org - Git at Google

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "chromeos/accelerometer/accelerometer_reader.h"

 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/task_runner.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"

 namespace chromeos {

 namespace {

 // Paths to access necessary data from the accelerometer device.
 const base::FilePath::CharType kAccelerometerTriggerPath[] =
     FILE_PATH_LITERAL("/sys/bus/iio/devices/trigger0/trigger_now");
 const base::FilePath::CharType kAccelerometerDevicePath[] =
     FILE_PATH_LITERAL("/dev/cros-ec-accel");
 const base::FilePath::CharType kAccelerometerIioBasePath[] =
     FILE_PATH_LITERAL("/sys/bus/iio/devices/");

 // File within the device in kAccelerometerIioBasePath containing the scale of
 // the accelerometers.
 const base::FilePath::CharType kScaleNameFormatString[] = "in_accel_%s_scale";

 // The filename giving the path to read the scan index of each accelerometer
 // axis.
 const char kAccelerometerScanIndexPath[] =
     "scan_elements/in_accel_%s_%s_index";

 // The names of the accelerometers. Matches up with the enum AccelerometerSource
 // in ui/accelerometer/accelerometer_types.h.
 const char kAccelerometerNames[ui::ACCELEROMETER_SOURCE_COUNT][5] = {
     "lid", "base"};

 // The axes on each accelerometer.
 const char kAccelerometerAxes[][2] = {"y", "x", "z"};

 // The length required to read uint values from configuration files.
 const size_t kMaxAsciiUintLength = 21;

 // The size of individual values.
 const size_t kDataSize = 2;

 // The time to wait between reading the accelerometer.
 const int kDelayBetweenReadsMs = 100;

 // The mean acceleration due to gravity on Earth in m/s^2.
 const float kMeanGravity = 9.80665f;

 // Reads |path| to the unsigned int pointed to by |value|. Returns true on
 // success or false on failure.
 bool ReadFileToInt(const base::FilePath& path, int* value) {
   std::string s;
   DCHECK(value);
   if (!base::ReadFileToString(path, &s, kMaxAsciiUintLength)) {
     return false;
   }
   base::TrimWhitespaceASCII(s, base::TRIM_ALL, &s);
   if (!base::StringToInt(s, value)) {
     LOG(ERROR) << "Failed to parse \"" << s << "\" from " << path.value();
     return false;
   }
   return true;
 }

 bool DetectAndReadAccelerometerConfiguration(
     scoped_refptr<AccelerometerReader::Configuration> configuration) {
   // Check for accelerometer symlink which will be created by the udev rules
   // file on detecting the device.
   base::FilePath device;
   if (!base::ReadSymbolicLink(base::FilePath(kAccelerometerDevicePath),
                               &device)) {
     return false;
   }

   if (!base::PathExists(base::FilePath(kAccelerometerTriggerPath))) {
     LOG(ERROR) << "Accelerometer trigger does not exist at"
                << kAccelerometerTriggerPath;
     return false;
   }

   base::FilePath iio_path(base::FilePath(kAccelerometerIioBasePath).Append(
       device));
   // Read configuration of each accelerometer axis from each accelerometer from
   // /sys/bus/iio/devices/iio:deviceX/.
   for (size_t i = 0; i < arraysize(kAccelerometerNames); ++i) {
     // Read scale of accelerometer.
     std::string accelerometer_scale_path = base::StringPrintf(
         kScaleNameFormatString, kAccelerometerNames[i]);
     int scale_divisor;
     if (!ReadFileToInt(iio_path.Append(accelerometer_scale_path.c_str()),
         &scale_divisor)) {
       configuration->data.has[i] = false;
       continue;
     }

     configuration->data.has[i] = true;
     configuration->data.count++;
     for (size_t j = 0; j < arraysize(kAccelerometerAxes); ++j) {
       configuration->data.scale[i][j] = kMeanGravity / scale_divisor;
       std::string accelerometer_index_path = base::StringPrintf(
           kAccelerometerScanIndexPath, kAccelerometerAxes[j],
           kAccelerometerNames[i]);
       if (!ReadFileToInt(iio_path.Append(accelerometer_index_path.c_str()),
                          &(configuration->data.index[i][j]))) {
         return false;
       }
     }
   }

   // Adjust the directions of accelerometers to match the AccelerometerUpdate
   // type specified in ui/accelerometer/accelerometer_types.h.
   configuration->data.scale[ui::ACCELEROMETER_SOURCE_SCREEN][0] *= -1.0f;
   for (int i = 0; i < 3; ++i) {
     configuration->data.scale[ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD][i] *=
         -1.0f;
   }

   // Verify indices are within bounds.
   for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
     if (!configuration->data.has[i])
       continue;
     for (int j = 0; j < 3; ++j) {
       if (configuration->data.index[i][j] < 0 ||
           configuration->data.index[i][j] >=
               3 * static_cast<int>(configuration->data.count)) {
         LOG(ERROR) << "Field index for " << kAccelerometerNames[i] << " "
                    << kAccelerometerAxes[j] << " axis out of bounds.";
         return false;
       }
     }
   }
   configuration->data.length = kDataSize * 3 * configuration->data.count;
   return true;
 }

 bool ReadAccelerometer(
     scoped_refptr<AccelerometerReader::Reading> reading,
     size_t length) {
   // Initiate the trigger to read accelerometers simultaneously
   int bytes_written = base::WriteFile(
       base::FilePath(kAccelerometerTriggerPath), "1\n", 2);
   if (bytes_written < 2) {
     PLOG(ERROR) << "Accelerometer trigger failure: " << bytes_written;
     return false;
   }

   // Read resulting sample from /dev/cros-ec-accel.
   int bytes_read = base::ReadFile(base::FilePath(kAccelerometerDevicePath),
                                   reading->data, length);
   if (bytes_read < static_cast<int>(length)) {
     LOG(ERROR) << "Read " << bytes_read << " byte(s), expected "
                << length << " bytes from accelerometer";
     return false;
   }
   return true;
 }

 }  // namespace

 AccelerometerReader::ConfigurationData::ConfigurationData()
     : count(0) {
   for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
     has[i] = false;
     for (int j = 0; j < 3; ++j) {
       scale[i][j] = 0;
       index[i][j] = -1;
     }
   }
 }

 AccelerometerReader::ConfigurationData::~ConfigurationData() {
 }

 AccelerometerReader::AccelerometerReader(
     scoped_refptr<base::TaskRunner> blocking_task_runner,
     AccelerometerReader::Delegate* delegate)
     : task_runner_(blocking_task_runner),
       delegate_(delegate),
       configuration_(new AccelerometerReader::Configuration()),
       weak_factory_(this) {
   DCHECK(task_runner_.get());
   DCHECK(delegate_);
   // Asynchronously detect and initialize the accelerometer to avoid delaying
   // startup.
   base::PostTaskAndReplyWithResult(task_runner_.get(), FROM_HERE,
       base::Bind(&DetectAndReadAccelerometerConfiguration, configuration_),
       base::Bind(&AccelerometerReader::OnInitialized,
                  weak_factory_.GetWeakPtr(), configuration_));
 }

 AccelerometerReader::~AccelerometerReader() {
 }

 void AccelerometerReader::OnInitialized(
     scoped_refptr<AccelerometerReader::Configuration> configuration,
     bool success) {
   if (success)
     TriggerRead();
 }

 void AccelerometerReader::TriggerRead() {
   DCHECK(!task_runner_->RunsTasksOnCurrentThread());

   scoped_refptr<AccelerometerReader::Reading> reading(
       new AccelerometerReader::Reading());
   base::PostTaskAndReplyWithResult(task_runner_.get(),
                                    FROM_HERE,
                                    base::Bind(&ReadAccelerometer, reading,
                                               configuration_->data.length),
                                    base::Bind(&AccelerometerReader::OnDataRead,
                                               weak_factory_.GetWeakPtr(),
                                               reading));
 }

 void AccelerometerReader::OnDataRead(
     scoped_refptr<AccelerometerReader::Reading> reading,
     bool success) {
   DCHECK(!task_runner_->RunsTasksOnCurrentThread());

   if (success) {
     for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
       if (!configuration_->data.has[i])
         continue;

       int16* values = reinterpret_cast<int16*>(reading->data);
       update_.Set(static_cast<ui::AccelerometerSource>(i),
                   values[configuration_->data.index[i][0]] *
                       configuration_->data.scale[i][0],
                   values[configuration_->data.index[i][1]] *
                       configuration_->data.scale[i][1],
                   values[configuration_->data.index[i][2]] *
                       configuration_->data.scale[i][2]);
     }
     delegate_->HandleAccelerometerUpdate(update_);
   }

   // Trigger another read after the current sampling delay.
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&AccelerometerReader::TriggerRead,
                  weak_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kDelayBetweenReadsMs));
 }

 }  // namespace chromeos
	// Copyright 2014 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "chromeos/accelerometer/accelerometer_reader.h"

	#include "base/bind.h"
	#include "base/files/file_util.h"
	#include "base/location.h"
	#include "base/message_loop/message_loop.h"
	#include "base/strings/string_number_conversions.h"
	#include "base/strings/string_util.h"
	#include "base/strings/stringprintf.h"
	#include "base/task_runner.h"
	#include "base/task_runner_util.h"
	#include "base/threading/sequenced_worker_pool.h"

	namespace chromeos {

	namespace {

	// Paths to access necessary data from the accelerometer device.
	const base::FilePath::CharType kAccelerometerTriggerPath[] =
	FILE_PATH_LITERAL("/sys/bus/iio/devices/trigger0/trigger_now");
	const base::FilePath::CharType kAccelerometerDevicePath[] =
	FILE_PATH_LITERAL("/dev/cros-ec-accel");
	const base::FilePath::CharType kAccelerometerIioBasePath[] =
	FILE_PATH_LITERAL("/sys/bus/iio/devices/");

	// File within the device in kAccelerometerIioBasePath containing the scale of
	// the accelerometers.
	const base::FilePath::CharType kScaleNameFormatString[] = "in_accel_%s_scale";

	// The filename giving the path to read the scan index of each accelerometer
	// axis.
	const char kAccelerometerScanIndexPath[] =
	"scan_elements/in_accel_%s_%s_index";

	// The names of the accelerometers. Matches up with the enum AccelerometerSource
	// in ui/accelerometer/accelerometer_types.h.
	const char kAccelerometerNames[ui::ACCELEROMETER_SOURCE_COUNT][5] = {
	"lid", "base"};

	// The axes on each accelerometer.
	const char kAccelerometerAxes[][2] = {"y", "x", "z"};

	// The length required to read uint values from configuration files.
	const size_t kMaxAsciiUintLength = 21;

	// The size of individual values.
	const size_t kDataSize = 2;

	// The time to wait between reading the accelerometer.
	const int kDelayBetweenReadsMs = 100;

	// The mean acceleration due to gravity on Earth in m/s^2.
	const float kMeanGravity = 9.80665f;

	// Reads \|path\| to the unsigned int pointed to by \|value\|. Returns true on
	// success or false on failure.
	bool ReadFileToInt(const base::FilePath& path, int* value) {
	std::string s;
	DCHECK(value);
	if (!base::ReadFileToString(path, &s, kMaxAsciiUintLength)) {
	return false;
	}
	base::TrimWhitespaceASCII(s, base::TRIM_ALL, &s);
	if (!base::StringToInt(s, value)) {
	LOG(ERROR) << "Failed to parse \"" << s << "\" from " << path.value();
	return false;
	}
	return true;
	}

	bool DetectAndReadAccelerometerConfiguration(
	scoped_refptr<AccelerometerReader::Configuration> configuration) {
	// Check for accelerometer symlink which will be created by the udev rules
	// file on detecting the device.
	base::FilePath device;
	if (!base::ReadSymbolicLink(base::FilePath(kAccelerometerDevicePath),
	&device)) {
	return false;
	}

	if (!base::PathExists(base::FilePath(kAccelerometerTriggerPath))) {
	LOG(ERROR) << "Accelerometer trigger does not exist at"
	<< kAccelerometerTriggerPath;
	return false;
	}

	base::FilePath iio_path(base::FilePath(kAccelerometerIioBasePath).Append(
	device));
	// Read configuration of each accelerometer axis from each accelerometer from
	// /sys/bus/iio/devices/iio:deviceX/.
	for (size_t i = 0; i < arraysize(kAccelerometerNames); ++i) {
	// Read scale of accelerometer.
	std::string accelerometer_scale_path = base::StringPrintf(
	kScaleNameFormatString, kAccelerometerNames[i]);
	int scale_divisor;
	if (!ReadFileToInt(iio_path.Append(accelerometer_scale_path.c_str()),
	&scale_divisor)) {
	configuration->data.has[i] = false;
	continue;
	}

	configuration->data.has[i] = true;
	configuration->data.count++;
	for (size_t j = 0; j < arraysize(kAccelerometerAxes); ++j) {
	configuration->data.scale[i][j] = kMeanGravity / scale_divisor;
	std::string accelerometer_index_path = base::StringPrintf(
	kAccelerometerScanIndexPath, kAccelerometerAxes[j],
	kAccelerometerNames[i]);
	if (!ReadFileToInt(iio_path.Append(accelerometer_index_path.c_str()),
	&(configuration->data.index[i][j]))) {
	return false;
	}
	}
	}

	// Adjust the directions of accelerometers to match the AccelerometerUpdate
	// type specified in ui/accelerometer/accelerometer_types.h.
	configuration->data.scale[ui::ACCELEROMETER_SOURCE_SCREEN][0] *= -1.0f;
	for (int i = 0; i < 3; ++i) {
	configuration->data.scale[ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD][i] *=
	-1.0f;
	}

	// Verify indices are within bounds.
	for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
	if (!configuration->data.has[i])
	continue;
	for (int j = 0; j < 3; ++j) {
	if (configuration->data.index[i][j] < 0 \|\|
	configuration->data.index[i][j] >=
	3 * static_cast<int>(configuration->data.count)) {
	LOG(ERROR) << "Field index for " << kAccelerometerNames[i] << " "
	<< kAccelerometerAxes[j] << " axis out of bounds.";
	return false;
	}
	}
	}
	configuration->data.length = kDataSize * 3 * configuration->data.count;
	return true;
	}

	bool ReadAccelerometer(
	scoped_refptr<AccelerometerReader::Reading> reading,
	size_t length) {
	// Initiate the trigger to read accelerometers simultaneously
	int bytes_written = base::WriteFile(
	base::FilePath(kAccelerometerTriggerPath), "1\n", 2);
	if (bytes_written < 2) {
	PLOG(ERROR) << "Accelerometer trigger failure: " << bytes_written;
	return false;
	}

	// Read resulting sample from /dev/cros-ec-accel.
	int bytes_read = base::ReadFile(base::FilePath(kAccelerometerDevicePath),
	reading->data, length);
	if (bytes_read < static_cast<int>(length)) {
	LOG(ERROR) << "Read " << bytes_read << " byte(s), expected "
	<< length << " bytes from accelerometer";
	return false;
	}
	return true;
	}

	} // namespace

	AccelerometerReader::ConfigurationData::ConfigurationData()
	: count(0) {
	for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
	has[i] = false;
	for (int j = 0; j < 3; ++j) {
	scale[i][j] = 0;
	index[i][j] = -1;
	}
	}
	}

	AccelerometerReader::ConfigurationData::~ConfigurationData() {
	}

	AccelerometerReader::AccelerometerReader(
	scoped_refptr<base::TaskRunner> blocking_task_runner,
	AccelerometerReader::Delegate* delegate)
	: task_runner_(blocking_task_runner),
	delegate_(delegate),
	configuration_(new AccelerometerReader::Configuration()),
	weak_factory_(this) {
	DCHECK(task_runner_.get());
	DCHECK(delegate_);
	// Asynchronously detect and initialize the accelerometer to avoid delaying
	// startup.
	base::PostTaskAndReplyWithResult(task_runner_.get(), FROM_HERE,
	base::Bind(&DetectAndReadAccelerometerConfiguration, configuration_),
	base::Bind(&AccelerometerReader::OnInitialized,
	weak_factory_.GetWeakPtr(), configuration_));
	}

	AccelerometerReader::~AccelerometerReader() {
	}

	void AccelerometerReader::OnInitialized(
	scoped_refptr<AccelerometerReader::Configuration> configuration,
	bool success) {
	if (success)
	TriggerRead();
	}

	void AccelerometerReader::TriggerRead() {
	DCHECK(!task_runner_->RunsTasksOnCurrentThread());

	scoped_refptr<AccelerometerReader::Reading> reading(
	new AccelerometerReader::Reading());
	base::PostTaskAndReplyWithResult(task_runner_.get(),
	FROM_HERE,
	base::Bind(&ReadAccelerometer, reading,
	configuration_->data.length),
	base::Bind(&AccelerometerReader::OnDataRead,
	weak_factory_.GetWeakPtr(),
	reading));
	}

	void AccelerometerReader::OnDataRead(
	scoped_refptr<AccelerometerReader::Reading> reading,
	bool success) {
	DCHECK(!task_runner_->RunsTasksOnCurrentThread());

	if (success) {
	for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
	if (!configuration_->data.has[i])
	continue;

	int16* values = reinterpret_cast<int16*>(reading->data);
	update_.Set(static_cast<ui::AccelerometerSource>(i),
	values[configuration_->data.index[i][0]] *
	configuration_->data.scale[i][0],
	values[configuration_->data.index[i][1]] *
	configuration_->data.scale[i][1],
	values[configuration_->data.index[i][2]] *
	configuration_->data.scale[i][2]);
	}
	delegate_->HandleAccelerometerUpdate(update_);
	}

	// Trigger another read after the current sampling delay.
	base::MessageLoop::current()->PostDelayedTask(
	FROM_HERE,
	base::Bind(&AccelerometerReader::TriggerRead,
	weak_factory_.GetWeakPtr()),
	base::TimeDelta::FromMilliseconds(kDelayBetweenReadsMs));
	}

	} // namespace chromeos