[sensors] Ambient light sensor implementation for ChromeOS and Linux.

device/generic_sensor/iio/sensor_data_iio.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 "device/generic_sensor/iio/sensor_data_iio.h"
+#include "device/sensors/public/cpp/device_sensors_consts.h"
+
+namespace device {
+
+namespace {
+
+using mojom::SensorType;
+
+const base::FilePath::CharType* kSensorsBasePath =
+    FILE_PATH_LITERAL("/sys/bus/iio/devices");
+
+const char* kAmbientLightFileNames[][5] = {
+    {"in_illuminance0_input", "in_illuminance_input", "in_illuminance0_raw",
+     "in_illuminance_raw", "illuminance0_input"}};
+
+// An exampleaw_content_browser_client.cc of other sensor:
+//
+// const char* kAccelerometerFileNames[3][3] = {
+//     { "x1", "x2", "x3", },
+//     { "y1", "y2", "y3", },
+//     { "z1", "z2", "z3", },
+// };
+
+}  // namespace
+
+bool InitSensorData(SensorType type, SensorDataIio* data) {
+  DCHECK(data);
+
+  switch (type) {
+    case SensorType::AMBIENT_LIGHT:
+      data->sensor_file_names[0] = &kAmbientLightFileNames[0][0];
+      data->sensor_file_names_cols = arraysize(*kAmbientLightFileNames);
+      data->sensor_file_names_rows = arraysize(kAmbientLightFileNames);
+      data->reporting_mode = mojom::ReportingMode::ON_CHANGE;
+      data->default_configuration =
+          PlatformSensorConfiguration(kDefaultAmbientLightFrequencyHz);
+      break;
+    default:
+      NOTIMPLEMENTED();
+      return false;
+  }
+  data->base_path_sensor_iio = kSensorsBasePath;
+  return true;
+}
+
+}  // namespace device