driver/src/backlight_driver.h

// Copyright 2022 The Fuchsia 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 FUCHSIA_DRIVERS_MISC_GOOGLE_BACKLIGHT_SRC_BACKLIGHT_DRIVER_H_
#define FUCHSIA_DRIVERS_MISC_GOOGLE_BACKLIGHT_SRC_BACKLIGHT_DRIVER_H_

#include <lib/driver/component/cpp/driver_cpp.h>

#include "driver/src/backlight_manager.h"

namespace backlight_driver {
constexpr uint64_t kMaxBacklight = 100;

// Animation starts with the maximum backlight, dims down to the minimum for a bit
// then starts increasing brightness again to the max and repeats.
constexpr zx::duration kAnimationInterval = zx::msec(50);
constexpr std::array kAnimation = {100, 100, 100, 100, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10,
                                   1,   1,   1,   1,   1,   10, 20, 30, 40, 50, 60, 70, 80, 90};

// Animation runs for 20 seconds.
const zx::duration kAnimationDuration = zx::sec(20);

class BacklightDriver : public driver::DriverBase {
 public:
  BacklightDriver(driver::DriverStartArgs start_args, fdf::UnownedDispatcher driver_dispatcher)
      : driver::DriverBase("chromeos-keyboard-led", std::move(start_args),
                           std::move(driver_dispatcher)) {}

  ~BacklightDriver() = default;

  zx::result<> Start() override;

 private:
  // Initializes the BacklightManager.
  zx::result<> Initialize();

  void StartBacklightBreathing();

  // Implements the breathing backlight. The next_index is used to index the kAnimation array.
  // Stops after kAnimationDuration.
  void BreathingBacklightImpl(int next_index);

  std::optional<BacklightManager> backlight_manager_;
  zx::time breathing_start;
};

}  // namespace backlight_driver

FUCHSIA_DRIVER_RECORD_CPP_V2(driver::Record<backlight_driver::BacklightDriver>);

#endif  // FUCHSIA_DRIVERS_MISC_GOOGLE_BACKLIGHT_SRC_BACKLIGHT_DRIVER_H_