/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011,2012 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @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.                                                         */
/*===========================================================================*/

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

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

/** SLA+R transmitted with ACK response */
#define TWI_MASTER_RX_ADDR_ACK     0x40
/** SLA+R transmitted with NACK response */
#define TWI_MASTER_RX_ADDR_NACK    0x48
/** DATA received with ACK response */
#define TWI_MASTER_RX_DATA_ACK     0x50
/** 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_ */

/** @} */