tlbmc/hal/led/led_sysfs.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_SYSFS_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_SYSFS_H_

#include <cstdint>
#include <memory>
#include <string>

#include "absl/base/thread_annotations.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "led_config.pb.h"
#include "tlbmc/hal/led/led.h"
#include "tlbmc/hal/sysfs/led.h"

namespace milotic_tlbmc {
// LED backed by the Linux LED sysfs subsystem.
//
// Reuses the LedSysfs HAL to translate high-level LedBehavior into sysfs
// attribute writes:
//   - LED_STATE_OFF:   trigger="none", brightness=0.
//   - LED_STATE_ON:    trigger="none", brightness=max_brightness.
//   - LED_STATE_BLINK: trigger="timer", delay_on/delay_off derived from the
//                      blink period and duty cycle. Blinking is handled by the
//                      kernel timer trigger, so no software timer is required.
//
// This class is thread-safe.
class SysfsLed : public Led {
 public:
  static absl::StatusOr<std::unique_ptr<SysfsLed>> Create(
      const LedConfig& config, const LedSysfs& led_sysfs);

 protected:
  absl::Status SetBehaviorImpl(const LedBehavior& behavior)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_) override;
  absl::StatusOr<LedBehavior> GetBehaviorImpl() const
      ABSL_SHARED_LOCKS_REQUIRED(mutex_) override;

  SysfsLed(const LedConfig& config, const LedSysfs& led_sysfs,
           uint32_t max_brightness = 255)
      : Led(config),
        led_sysfs_(led_sysfs),
        sysfs_name_(config.output().sysfs_name()),
        max_brightness_(max_brightness) {}

 private:
  const LedSysfs& led_sysfs_;
  const std::string sysfs_name_;
  const uint32_t max_brightness_;
};

}  // namespace milotic_tlbmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_SYSFS_H_