peripheralmanager/daemon/fake_i2c_devices.cc

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "fake_i2c_devices.h"

#include <base/logging.h>
#include <linux/i2c-dev.h>
#include <linux/i2c.h>

namespace android {

FakeI2cDevice::FakeI2cDevice() {}
FakeI2cDevice::~FakeI2cDevice() {}

int FakeI2cDevice::Open(const char* pathname, int flags) {
  return 1;
}

int FakeI2cDevice::Close(int fd) {
  return 0;
}

int FakeI2cDevice::Ioctl(int fd, int request, void* argp) {
  if (request == I2C_SMBUS) {
    struct i2c_smbus_ioctl_data* smbus_args =
        reinterpret_cast<struct i2c_smbus_ioctl_data*>(argp);

    if (smbus_args->read_write == I2C_SMBUS_WRITE) {
      uint8_t* data = smbus_args->data->block;
      std::vector<uint8_t> temp;
      if (smbus_args->size == I2C_SMBUS_I2C_BLOCK_DATA) {
        temp.assign(data + 1, data + data[0] + 1);
      } else if (smbus_args->size == I2C_SMBUS_WORD_DATA) {
        temp.assign(data, data + 2);
      } else if (smbus_args->size == I2C_SMBUS_BYTE_DATA) {
        temp.assign(data, data + 1);
      }

      registers_.emplace(smbus_args->command, temp);
      LOG(INFO) << "writing " << temp.size() << " elements in "
                << smbus_args->command;
      return 0;
    } else if (smbus_args->read_write == I2C_SMBUS_READ) {
      if (!registers_.count(smbus_args->command)) {
        LOG(INFO) << "no such register";
        return -1;
      }
      auto reg = registers_.find(smbus_args->command);
      LOG(INFO) << "reading register " << smbus_args->command << " that has "
                << reg->second.size() << " elements";

      if (smbus_args->size == I2C_SMBUS_I2C_BLOCK_DATA) {
        memcpy(smbus_args->data->block + 1,
               reg->second.data(),
               smbus_args->data->block[0]);
      } else if (smbus_args->size == I2C_SMBUS_WORD_DATA) {
        memcpy(smbus_args->data->block, reg->second.data(), 2);
      } else if (smbus_args->size == I2C_SMBUS_BYTE_DATA) {
        memcpy(smbus_args->data->block, reg->second.data(), 1);
      }
      return 0;
    }
  } else if (request == I2C_SLAVE) {
    return 0;
  }

  return -1;
}

ssize_t FakeI2cDevice::Read(int fd, void* buf, size_t count) {
  return count;
}

ssize_t FakeI2cDevice::Write(int fd, const void* buf, size_t count) {
  return count;
}

int FakeI2cDevice::Poll(struct pollfd* fds, nfds_t nfds, int timeout) {
  return 0;
}

FakeI2cDeviceFactory::FakeI2cDeviceFactory() {}

FakeI2cDeviceFactory::~FakeI2cDeviceFactory() {}

std::unique_ptr<CharDeviceInterface> FakeI2cDeviceFactory::NewCharDevice() {
  return std::unique_ptr<CharDeviceInterface>(new FakeI2cDevice());
}

}  // namespace android