tlbmc/hal/gpio/gpio.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_GPIO_GPIO_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_GPIO_GPIO_H_

#include <gpiod.h>

#include <memory>
#include <string>
#include <utility>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "gpio_config.pb.h"

namespace milotic_tlbmc {
namespace internal {
// Custom deleter for gpiod_line using gpiod_line_release.
struct GpioLineDeleter {
  void operator()(gpiod_line* line) const {
    if (line != nullptr) {
      gpiod_line_release(line);
    }
  }
};

absl::StatusOr<int> ParseGpioRequestType(const GpioConfig& config);
}  // namespace internal

class Gpio {
 public:
  // unique_ptr alias for gpiod_line.
  using GpioLineUniquePtr =
      std::unique_ptr<gpiod_line, internal::GpioLineDeleter>;

  // Don't need to close the event fd in the destructor.
  // It's covered in the gpiod_line_release when the unique_ptr of gpio_line
  // is destructed.
  ~Gpio() = default;

  // Gpio is a resource-managing class and should not be copied or moved.
  Gpio(const Gpio&) = delete;
  Gpio& operator=(const Gpio&) = delete;
  Gpio(Gpio&&) = delete;
  Gpio& operator=(Gpio&&) = delete;

  absl::StatusOr<bool> GetValue() const;

  // Set the GPIO line value. True to set the GPIO line to 1(HIGH), false to set
  // the GPIO line to 0(LOW).
  absl::Status SetValue(bool value);

  // Get the GPIO name. Returns the line name if it is set, otherwise returns
  // "<chip id>:<gpio num>".
  std::string GetGpioName() const;

  // Get the GPIO line event file descriptor. This is used to monitor the GPIO
  // line.
  int GetGpioLineEventFd() const { return event_fd_; };

  static absl::StatusOr<std::unique_ptr<Gpio>> Create(const GpioConfig& config);

 protected:
  Gpio(const GpioConfig& config, GpioLineUniquePtr gpio_line, int event_fd)
      : config_(config),
        gpio_line_(std::move(gpio_line)),
        event_fd_(event_fd) {}

 private:
  const GpioConfig config_;
  // The GPIO line, managed by unique_ptr with a custom deleter.
  GpioLineUniquePtr gpio_line_;
  // The file descriptor of the GPIO line event. This is only used when the GPIO
  // line is requested for event monitoring.
  int event_fd_;
};

}  // namespace milotic_tlbmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_GPIO_GPIO_H_