tlbmc/hal/sysfs/i2c.cc

#include "tlbmc/hal/sysfs/i2c.h"

#include <cstdint>
#include <fstream>
#include <string>
#include <string_view>

#include "absl/status/status.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/substitute.h"
#include "i2c_common_config.pb.h"

namespace milotic_tlbmc {

boost::filesystem::path I2cSysfs::Geti2cBusPath(uint64_t bus) const {
  boost::filesystem::path path(config_.i2c_sysfs_path);
  path /= "i2c-";
  return absl::Substitute(path.string() + "$0", bus);
}

absl::Status I2cSysfs::NewDevice(const I2cCommonConfig& config,
                                 std::string_view driver_name) const {
  if (IsDevicePresent(config)) {
    return absl::AlreadyExistsError(
        absl::Substitute("Device $0 already exists", config));
  }

  boost::filesystem::path path = Geti2cBusPath(config.bus()) / "new_device";

  std::ofstream file(path.string());
  if (!file.good()) {
    return absl::InternalError(
        absl::Substitute("Failed to open $0", path.string()));
  }

  file << driver_name << " " << config.address() << "\n";
  file.flush();

  if (!file.good()) {
    return absl::InternalError(
        absl::Substitute("Failed to write to $0", path.string()));
  }

  return absl::OkStatus();
}

absl::Status I2cSysfs::DeleteDevice(const I2cCommonConfig& config) const {
  // No `IsDevicePresent` check on this like in `NewDevice`, since it
  // might be used to clean up after a device instantiation that was only
  // partially successful

  boost::filesystem::path path = Geti2cBusPath(config.bus()) / "delete_device";
  std::ofstream file(path.string());
  if (!file.good()) {
    return absl::InternalError(
        absl::Substitute("Failed to open $0", path.string()));
  }
  file << config.address() << "\n";
  file.flush();
  if (!file.good()) {
    return absl::InternalError(
        absl::Substitute("Failed to write to $0", path.string()));
  }
  return absl::OkStatus();
}

bool I2cSysfs::IsDevicePresent(const I2cCommonConfig& config) const {
  boost::filesystem::path path = Geti2cBusPath(config.bus());
  path /= GetDeviceDirectoryName(config);
  return boost::filesystem::exists(path);
}

std::string I2cSysfs::GetDeviceDirectoryName(const I2cCommonConfig& config) {
  return absl::Substitute(
      "$0-$1", config.bus(),
      absl::StrCat(absl::Hex(config.address(), absl::kZeroPad4)));
}

}  // namespace milotic_tlbmc