[sensors][CrOS/Linux] Implementation of motion sensors for CrOS/Linux platforms

device/generic_sensor/linux/sensor_data_linux.cc

 // Copyright 2016 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 "base/sys_info.h"
+#include "base/version.h"
+#include "device/generic_sensor/generic_sensor_consts.h"
 #include "device/generic_sensor/linux/sensor_data_linux.h"
-#include "device/sensors/public/cpp/device_sensors_consts.h"
+#include "device/generic_sensor/public/cpp/sensor_reading.h"
 
 namespace device {
 
 namespace {
 
 using mojom::SensorType;
 
+#if defined(OS_CHROMEOS)
+// ChromeOS kernel version, when axes were changed to XYZ. Before 3.18,
+// they were YXZ.
+const char kChangedAxisKernelVersion[] = "3.18.0";
+#endif
+
 const base::FilePath::CharType* kSensorsBasePath =
     FILE_PATH_LITERAL("/sys/bus/iio/devices");
 
 void InitAmbientLightSensorData(SensorDataLinux* data) {
   std::vector<std::string> file_names{
       "in_illuminance0_input", "in_illuminance_input", "in_illuminance0_raw",
       "in_illuminance_raw"};
-
   data->sensor_file_names.push_back(std::move(file_names));
   data->reporting_mode = mojom::ReportingMode::ON_CHANGE;
   data->default_configuration =
       PlatformSensorConfiguration(kDefaultAmbientLightFrequencyHz);
 }
 
+// Depending on a kernel version, CrOS has a different axes plane.
+// Before 3.18 it was YXZ and after XYZ.
+// TODO(maksims): Track crbug.com/501184. 3.14 will have the same sensor stack
+// as 3.18 has, which will probably change the order of axes.
+void MaybeCheckKernelVersionAndAssignFileNames(
+    const std::vector<std::string>& file_names_x,
+    const std::vector<std::string>& file_names_y,
+    const std::vector<std::string>& file_names_z,
+    SensorDataLinux* data) {
+#if defined(OS_CHROMEOS)
+  const base::Version checked_kernel_version(kChangedAxisKernelVersion);
+  DCHECK(checked_kernel_version.IsValid());
+  const base::Version current_version(base::SysInfo::OperatingSystemVersion());
+  if (current_version.IsValid() && current_version < checked_kernel_version) {
+    data->sensor_file_names.push_back(file_names_y);
+    data->sensor_file_names.push_back(file_names_x);
+  } else {
+    data->sensor_file_names.push_back(file_names_x);
+    data->sensor_file_names.push_back(file_names_y);
+  }
+  data->sensor_file_names.push_back(file_names_z);
+#else
+  data->sensor_file_names.push_back(file_names_x);
+  data->sensor_file_names.push_back(file_names_y);
+  data->sensor_file_names.push_back(file_names_z);
+#endif
+}
+
+// TODO(maksims): add support for lid accelerometer on chromeos.
+void InitAccelerometerSensorData(SensorDataLinux* data) {
+  std::vector<std::string> file_names_x{"in_accel_x_base_raw",
+                                        "in_accel_x_raw"};
+  std::vector<std::string> file_names_y{"in_accel_y_base_raw",
+                                        "in_accel_y_raw"};
+  std::vector<std::string> file_names_z{"in_accel_z_base_raw",
+                                        "in_accel_z_raw"};
+
+#if defined(OS_CHROMEOS)
+  data->sensor_scale_name = "in_accel_base_scale";
+  data->apply_scaling_func =
+      base::Bind([](double scaling_value, SensorReading& reading) {
+        double scaling = kMeanGravity / scaling_value;
+        reading.values[0] = scaling * reading.values[0];
+        reading.values[1] = scaling * reading.values[1];
+        reading.values[2] = scaling * reading.values[2];
+      });
+#else
+  data->sensor_scale_name = "in_accel_scale";
+  data->apply_scaling_func =
+      base::Bind([](double scaling_value, SensorReading& reading) {
+        // Adapt Linux reading values to generic sensor api specs.
+        reading.values[0] = -scaling_value * reading.values[0];
+        reading.values[1] = -scaling_value * reading.values[1];
+        reading.values[2] = -scaling_value * reading.values[2];
+      });
+#endif
+
+  MaybeCheckKernelVersionAndAssignFileNames(file_names_x, file_names_y,
+                                            file_names_z, data);
+  data->reporting_mode = mojom::ReportingMode::CONTINUOUS;
+  data->default_configuration =
+      PlatformSensorConfiguration(kDefaultAccelerometerFrequencyHz);
+}
+
+void InitGyroscopeSensorData(SensorDataLinux* data) {
+  std::vector<std::string> file_names_x{"in_anglvel_x_base_raw",
+                                        "in_anglvel_x_raw"};
+  std::vector<std::string> file_names_y{"in_anglvel_y_base_raw",
+                                        "in_anglvel_y_raw"};
+  std::vector<std::string> file_names_z{"in_anglvel_z_base_raw",
+                                        "in_anglvel_z_raw"};
+#if defined(OS_CHROMEOS)
+  data->sensor_scale_name = "in_anglvel_base_scale";
+  data->apply_scaling_func =
+      base::Bind([](double scaling_value, SensorReading& reading) {
+        double scaling =
+            kMeanGravity * kRadiansInDegreesPerSecond / scaling_value;
+        // Adapt CrOS reading values to generic sensor api specs.
+        reading.values[0] = -scaling * reading.values[0];
+        reading.values[1] = -scaling * reading.values[1];
+        reading.values[2] = -scaling * reading.values[2];
+      });
+#else
+  data->sensor_scale_name = "in_anglvel_scale";
+  data->apply_scaling_func =
+      base::Bind([](double scaling_value, SensorReading& reading) {
+        reading.values[0] = scaling_value * reading.values[0];
+        reading.values[1] = scaling_value * reading.values[1];
+        reading.values[2] = scaling_value * reading.values[2];
+      });
+#endif
+
+  MaybeCheckKernelVersionAndAssignFileNames(file_names_x, file_names_y,
+                                            file_names_z, data);
+  data->reporting_mode = mojom::ReportingMode::CONTINUOUS;
+  data->default_configuration =
+      PlatformSensorConfiguration(kDefaultGyroscopeFrequencyHz);
+}
+
+// TODO(maksims): Verify magnitometer works correctly on a chromebook when
+// I get one with that sensor onboard.
+void InitMagnitometerSensorData(SensorDataLinux* data) {
+  std::vector<std::string> file_names_x{"in_magn_x_raw"};
+  std::vector<std::string> file_names_y{"in_magn_y_raw"};
+  std::vector<std::string> file_names_z{"in_magn_z_raw"};
+
+  data->sensor_scale_name = "in_magn_scale";
+  data->apply_scaling_func = base::Bind([](double scaling_value,
+                                           SensorReading& reading) {
+    reading.values[0] = scaling_value * kMicroteslaInGauss * reading.values[0];
+    reading.values[1] = scaling_value * kMicroteslaInGauss * reading.values[1];
+    reading.values[2] = scaling_value * kMicroteslaInGauss * reading.values[2];
+  });
+
+  MaybeCheckKernelVersionAndAssignFileNames(file_names_x, file_names_y,
+                                            file_names_z, data);
+  data->reporting_mode = mojom::ReportingMode::CONTINUOUS;
+  data->default_configuration =
+      PlatformSensorConfiguration(kDefaultMagnetometerFrequencyHz);
+}
+
 }  // namespace
 
 SensorDataLinux::SensorDataLinux() : base_path_sensor_linux(kSensorsBasePath) {}
 
 SensorDataLinux::~SensorDataLinux() = default;
 
 SensorDataLinux::SensorDataLinux(const SensorDataLinux& other) = default;
 
 bool InitSensorData(SensorType type, SensorDataLinux* data) {
   DCHECK(data);
 
   switch (type) {
-    case SensorType::AMBIENT_LIGHT: {
+    case SensorType::AMBIENT_LIGHT:
       InitAmbientLightSensorData(data);
       break;
-    }
-    default: {
+    case SensorType::ACCELEROMETER:
+      InitAccelerometerSensorData(data);
+      break;
+    case SensorType::GYROSCOPE:
+      InitGyroscopeSensorData(data);
+      break;
+    case SensorType::MAGNETOMETER:
+      InitMagnitometerSensorData(data);
+      break;
+    default:
       NOTIMPLEMENTED();
       return false;
-    }
   }
+
   return true;
 }
 
 }  // namespace device