/*
    ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio

    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.
*/

/**
 * @file    AVR/i2c_lld.h
 * @brief   AVR I2C subsystem low level driver header.
 *
 * @addtogroup I2C
 * @{
 */

#ifndef _I2C_LLD_H_
#define _I2C_LLD_H_

#if HAL_USE_I2C || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver constants.                                                         */
/*===========================================================================*/

/** @brief   START transmitted.*/
#define TWI_START                  0x08
/** @brief   Repeated START transmitted.*/
#define TWI_REPEAT_START           0x10
/** @brief   Arbitration Lost.*/
#define TWI_ARBITRATION_LOST       0x38
/** @brief   Bus errors.*/
#define TWI_BUS_ERROR              0x00

/** @brief   SLA+W transmitted with ACK response.*/
#define TWI_MASTER_TX_ADDR_ACK     0x18
/** @brief   SLA+W transmitted with NACK response.*/
#define TWI_MASTER_TX_ADDR_NACK    0x20
/** @brief   DATA transmitted with ACK response.*/
#define TWI_MASTER_TX_DATA_ACK     0x28
/** @brief   DATA transmitted with NACK response.*/
#define TWI_MASTER_TX_DATA_NACK    0x30

/** @brief   SLA+R transmitted with ACK response.*/
#define TWI_MASTER_RX_ADDR_ACK     0x40
/** @brief   SLA+R transmitted with NACK response.*/
#define TWI_MASTER_RX_ADDR_NACK    0x48
/** @brief   DATA received with ACK response.*/
#define TWI_MASTER_RX_DATA_ACK     0x50
/** @brief   DATA received with NACK response.*/
#define TWI_MASTER_RX_DATA_NACK    0x58

/*===========================================================================*/
/* Driver pre-compile time settings.                                         */
/*===========================================================================*/

/**
 * @name    Configuration options
 * @{
 */
/**
 * @brief   I2C driver enable switch.
 * @details If set to @p TRUE the support for I2C is included.
 * @note    The default is @p FALSE.
 */
#if !defined(USE_AVR_I2C) || defined(__DOXYGEN__)
#define USE_AVR_I2C              FALSE
#endif
/** @} */

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

/*===========================================================================*/
/* Driver data structures and types.                                         */
/*===========================================================================*/

/**
 * @brief   Type representing I2C address.
 */
typedef uint8_t i2caddr_t;

/**
 * @brief   I2C Driver condition flags type.
 */
typedef uint8_t i2cflags_t;

/**
 * @brief   Driver configuration structure.
 * @note    Implementations may extend this structure to contain more,
 *          architecture dependent, fields.
 */
typedef struct {

  /**
   * @brief Specifies the I2C clock frequency.
   */
  uint32_t        clock_speed;

} I2CConfig;

/**
 * @brief Structure representing an I2C driver.
 */
struct I2CDriver {
  /**
   * @brief   Driver state.
   */
  i2cstate_t                state;
  /**
   * @brief   Current configuration data.
   */
  const I2CConfig           *config;
  /**
   * @brief   Error flags.
   */
  i2cflags_t                errors;
#if I2C_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
#if CH_USE_MUTEXES || defined(__DOXYGEN__)
  /**
   * @brief   Mutex protecting the bus.
   */
  Mutex                     mutex;
#elif CH_USE_SEMAPHORES
  Semaphore                 semaphore;
#endif
#endif /* I2C_USE_MUTUAL_EXCLUSION */
#if defined(I2C_DRIVER_EXT_FIELDS)
  I2C_DRIVER_EXT_FIELDS
#endif
  /* End of the mandatory fields.*/
  /**
   * @brief   Thread waiting for I/O completion.
   */
  Thread                    *thread;
  /**
   * @brief   Address of slave device.
   */
  i2caddr_t                 addr;
  /**
   * @brief   Pointer to the buffer with data to send.
   */
  const uint8_t             *txbuf;
  /**
   * @brief   Number of bytes of data to send.
   */
  size_t                    txbytes;
  /**
   * @brief   Current index in buffer when sending data.
   */
  size_t                    txidx;
  /**
   * @brief   Pointer to the buffer to put received data.
   */
  uint8_t                   *rxbuf;
  /**
   * @brief   Number of bytes of data to receive.
   */
  size_t                    rxbytes;
  /**
   * @brief   Current index in buffer when receiving data.
   */
  size_t                    rxidx;
};

/**
 * @brief   Type of a structure representing an I2C driver.
 */
typedef struct I2CDriver I2CDriver;

/*===========================================================================*/
/* Driver macros.                                                            */
/*===========================================================================*/

/**
 * @brief   Get errors from I2C driver.
 *
 * @param[in] i2cp      pointer to the @p I2CDriver object
 *
 * @notapi
 */
#define i2c_lld_get_errors(i2cp) ((i2cp)->errors)

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#if !defined(__DOXYGEN__)
#if USE_AVR_I2C
extern I2CDriver I2CD;
#endif
#endif /* !defined(__DOXYGEN__) */

#ifdef __cplusplus
extern "C" {
#endif
  void i2c_lld_init(void);
  void i2c_lld_start(I2CDriver *i2cp);
  void i2c_lld_stop(I2CDriver *i2cp);
  msg_t i2c_lld_master_transmit_timeout(I2CDriver *i2cp, i2caddr_t addr,
                                        const uint8_t *txbuf, size_t txbytes,
                                        uint8_t *rxbuf, size_t rxbytes,
                                        systime_t timeout);
  msg_t i2c_lld_master_receive_timeout(I2CDriver *i2cp, i2caddr_t addr,
                                       uint8_t *rxbuf, size_t rxbytes,
                                       systime_t timeout);
#ifdef __cplusplus
}
#endif

#endif /* HAL_USE_I2C */

#endif /* _I2C_LLD_H_ */

/** @} */
