iio_temperature_sensor.cc

// Copyright 2019 The Chromium OS 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 "thermald/iio_temperature_sensor.h"

#include <string>

#include "base/check.h"
#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"

using std::stoi;
using std::string;
using std::to_string;

namespace thermald {

std::unique_ptr<IioTemperatureSensor>
IioTemperatureSensor::Get(const string &name, const string &iio_device_name,
                          const string &iio_sensor_name) {
  base::FilePath iio_device_dir("/sys/bus/iio/devices/");
  base::FileEnumerator iio_enum(iio_device_dir, false,
                                base::FileEnumerator::DIRECTORIES,
                                FILE_PATH_LITERAL("iio:device*"));

  base::FilePath iio_device;
  for (iio_device = iio_enum.Next(); !iio_device.empty();
       iio_device = iio_enum.Next()) {
    if (iio_device.BaseName().value() == iio_device_name) {
      break;
    }
  }

  if (iio_device.empty()) {
    return NULL;
  }

  return std::make_unique<IioTemperatureSensor>(name, iio_device,
                                                iio_sensor_name);
}

IioTemperatureSensor::IioTemperatureSensor(const string &name,
                                           const base::FilePath &iio_dev_path,
                                           const string &iio_sensor_name)
    : TemperatureSensorCommon(name),
      sysfs_attr_input_(iio_dev_path.value() + "/in_temp_" + iio_sensor_name) {
}

bool IioTemperatureSensor::ReadTemperature(int *value) {
  DCHECK(value);

  string contents;
  if (!base::ReadFileToString(sysfs_attr_input_, &contents)) {
    LOG(ERROR) << "[" << name() << "] Failed to read '"
               << sysfs_attr_input_.value() << "'";
    return false;
  }

  *value = stoi(contents);

  return true;
}

}  // namespace thermald