Read and expose accelerometer values from cros-ec-accel trigger.

chromeos/accelerometer/accelerometer_reader.h

+// 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.
+
+#ifndef CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
+#define CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
+
+#include <vector>
+
+#include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
+#include "chromeos/chromeos_export.h"
+
+namespace gfx {
+class Vector3dF;
+}
+
+namespace chromeos {
+
+// Reads an accelerometer device and reports data back to an
+// AccelerometerDelegate.
+class CHROMEOS_EXPORT AccelerometerReader {
+ public:
+  // An interface to receive data from the AccelerometerReader.
+  class Delegate {
+   public:
+    virtual void HandleAccelerometerReading(const gfx::Vector3dF& base,
+                                            const gfx::Vector3dF& lid) = 0;
+  };
+
+  AccelerometerReader(Delegate* delegate);
+  ~AccelerometerReader();
+
+ private:
+  // Detects and reads configuration of the accelerometer device.
+  bool Initialize();
+
+  // Triggers a read from the accelerometer, and posts a task to trigger another
+  // read after the sampling interval.
+  void TriggerRead();
+
+  // Triggers the accelerometer and reads the sampled values. On success,
+  // notifies the |delegate_| with the read values.
+  void ReadAccelerometer();
+
+  // A weak pointer to the delegate to send accelerometer readings to.
+  Delegate* delegate_;
+
+  // True after Initialize has run if an accelerometer sensor exists.
+  bool has_accelerometer_;
+
+  // The index of each axis of each accelerometer.
+  std::vector<unsigned int> accelerometer_index_;
+
+  // The scale of the base and lid accelerometers.
+  unsigned int accelerometer_base_scale_;
+  unsigned int accelerometer_lid_scale_;
+
+  base::WeakPtrFactory<AccelerometerReader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(AccelerometerReader);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_