/*
 * 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 "i2c_driver_i2cdev.h"

#include <fcntl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <string>

#include <base/logging.h>

namespace android {
namespace {

const char kI2cDevPath[] = "/dev/i2c-";

}  // namespace

I2cDriverI2cDev::I2cDriverI2cDev(CharDeviceFactory* char_device_factory)
    : fd_(-1), char_device_factory_(char_device_factory) {}

I2cDriverI2cDev::~I2cDriverI2cDev() {
  if (fd_ >= 0 && char_interface_ != nullptr) {
    char_interface_->Close(fd_);
  }
}

bool I2cDriverI2cDev::Init(uint32_t bus_id, uint32_t address) {
  if (fd_ >= 0) {
    return false;
  }
  // Get a char device. If char_device_factory_ is set
  // then this is a unittest and the char device is provided
  // by the test. Otherwise create a normal CharDevice.
  if (!char_device_factory_) {
    char_interface_.reset(new CharDevice());
  } else {
    char_interface_ = char_device_factory_->NewCharDevice();
  }

  std::string path = kI2cDevPath + std::to_string(bus_id);

  int fd = char_interface_->Open(path.c_str(), O_RDWR);
  if (fd < 0)
    return false;
  uintptr_t tmp_addr = address;
  if (char_interface_->Ioctl(fd, I2C_SLAVE, (void*)tmp_addr) < 0) {
    LOG(ERROR) << "Failed to set I2C slave";
    char_interface_->Close(fd);
    return false;
  }

  fd_ = fd;

  return true;
}

int32_t I2cDriverI2cDev::Read(void* data, uint32_t size, uint32_t* bytes_read) {
  *bytes_read = char_interface_->Read(fd_, data, size);
  return *bytes_read == size ? 0 : EIO;
}

int32_t I2cDriverI2cDev::ReadRegByte(uint8_t reg, uint8_t* val) {
  union i2c_smbus_data read_data;
  struct i2c_smbus_ioctl_data smbus_args {
    .command = reg, .read_write = I2C_SMBUS_READ, .size = I2C_SMBUS_BYTE_DATA,
    .data = &read_data,
  };

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    LOG(INFO) << "Failed I2C_SMBUS";
    return EIO;
  }

  *val = read_data.byte;
  return 0;
}

int32_t I2cDriverI2cDev::ReadRegWord(uint8_t reg, uint16_t* val) {
  union i2c_smbus_data read_data;
  struct i2c_smbus_ioctl_data smbus_args {
    .command = reg, .read_write = I2C_SMBUS_READ, .size = I2C_SMBUS_WORD_DATA,
    .data = &read_data,
  };

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    LOG(INFO) << "Failed I2C_SMBUS";
    return EIO;
  }

  *val = read_data.word;
  return 0;
}

int32_t I2cDriverI2cDev::ReadRegBuffer(uint8_t reg,
                                       uint8_t* data,
                                       uint32_t size,
                                       uint32_t* bytes_read) {
  *bytes_read = 0;
  if (size > I2C_SMBUS_BLOCK_MAX) {
    LOG(WARNING) << "Can't read more than 32 bytes at a time.";
    return EINVAL;
  }

  union i2c_smbus_data read_data;
  read_data.block[0] = size;

  struct i2c_smbus_ioctl_data smbus_args;
  smbus_args.command = reg;
  smbus_args.read_write = I2C_SMBUS_READ;
  smbus_args.size = I2C_SMBUS_I2C_BLOCK_DATA;
  smbus_args.data = &read_data;

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    LOG(ERROR) << "Failed I2C_SMBUS";
    return EIO;
  }

  memcpy(data, &read_data.block[1], size);
  *bytes_read = size;

  return 0;
}

int32_t I2cDriverI2cDev::Write(const void* data,
                               uint32_t size,
                               uint32_t* bytes_written) {
  *bytes_written = char_interface_->Write(fd_, data, size);
  return *bytes_written == size ? 0 : EIO;
}

int32_t I2cDriverI2cDev::WriteRegByte(uint8_t reg, uint8_t val) {
  union i2c_smbus_data write_data;
  write_data.byte = val;
  struct i2c_smbus_ioctl_data smbus_args;
  smbus_args.command = reg;
  smbus_args.read_write = I2C_SMBUS_WRITE;
  smbus_args.size = I2C_SMBUS_BYTE_DATA;
  smbus_args.data = &write_data;

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    return EIO;
  }
  return 0;
}

int32_t I2cDriverI2cDev::WriteRegWord(uint8_t reg, uint16_t val) {
  union i2c_smbus_data write_data;
  write_data.word = val;
  struct i2c_smbus_ioctl_data smbus_args;
  smbus_args.command = reg;
  smbus_args.read_write = I2C_SMBUS_WRITE;
  smbus_args.size = I2C_SMBUS_WORD_DATA;
  smbus_args.data = &write_data;

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    return EIO;
  }
  return 0;
}

int32_t I2cDriverI2cDev::WriteRegBuffer(uint8_t reg,
                                        const uint8_t* data,
                                        uint32_t size,
                                        uint32_t* bytes_written) {
  *bytes_written = 0;
  if (size > I2C_SMBUS_BLOCK_MAX) {
    LOG(WARNING) << "Can't write more than 32 bytes at a time.";
    return EINVAL;
  }

  union i2c_smbus_data write_data;
  write_data.block[0] = size;
  memcpy(&write_data.block[1], data, size);

  struct i2c_smbus_ioctl_data smbus_args;
  smbus_args.command = reg;
  smbus_args.read_write = I2C_SMBUS_WRITE;
  smbus_args.size = I2C_SMBUS_I2C_BLOCK_DATA;
  smbus_args.data = &write_data;

  if (char_interface_->Ioctl(fd_, I2C_SMBUS, &smbus_args) < 0) {
    LOG(ERROR) << "Failed I2C_SMBUS";
    return EIO;
  }

  *bytes_written = size;

  return 0;
}

}  // namespace