/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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    i2c.c
 * @brief   I2C Driver code.
 *
 * @addtogroup I2C
 * @{
 */

#include "ch.h"
#include "hal.h"

#if HAL_USE_I2C || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   I2C Driver initialization.
 * @note    This function is implicitly invoked by @p halInit(), there is
 *          no need to explicitly initialize the driver.
 *
 * @init
 */
void i2cInit(void) {
  i2c_lld_init();
}

/**
 * @brief   Initializes the standard part of a @p I2CDriver structure.
 *
 * @param[out] i2cp     pointer to the @p I2CDriver object
 *
 * @init
 */
void i2cObjectInit(I2CDriver *i2cp) {

  i2cp->id_state  = I2C_STOP;
  i2cp->id_config = NULL;
  i2cp->id_slave_config = NULL;

#if I2C_USE_WAIT
  i2cp->id_thread   = NULL;
#endif /* I2C_USE_WAIT */

#if I2C_USE_MUTUAL_EXCLUSION
#if CH_USE_MUTEXES
  chMtxInit(&i2cp->id_mutex);
#else
  chSemInit(&i2cp->id_semaphore, 1);
#endif /* CH_USE_MUTEXES */
#endif /* I2C_USE_MUTUAL_EXCLUSION */

#if defined(I2C_DRIVER_EXT_INIT_HOOK)
  I2C_DRIVER_EXT_INIT_HOOK(i2cp);
#endif
}

/**
 * @brief   Configures and activates the I2C peripheral.
 *
 * @param[in] i2cp      pointer to the @p I2CDriver object
 * @param[in] config    pointer to the @p I2CConfig object
 *
 * @api
 */
void i2cStart(I2CDriver *i2cp, I2CConfig *config) {

  chDbgCheck((i2cp != NULL) && (config != NULL), "i2cStart");

  chSysLock();
  chDbgAssert((i2cp->id_state == I2C_STOP) || (i2cp->id_state == I2C_READY),
              "i2cStart(), #1",
              "invalid state");
  i2cp->id_config = config;
  i2c_lld_start(i2cp);
  i2cp->id_state = I2C_READY;
  chSysUnlock();
}

/**
 * @brief   Deactivates the I2C peripheral.
 *
 * @param[in] i2cp      pointer to the @p I2CDriver object
 *
 * @api
 */
void i2cStop(I2CDriver *i2cp) {

  chDbgCheck(i2cp != NULL, "i2cStop");

  chSysLock();
  chDbgAssert((i2cp->id_state == I2C_STOP) || (i2cp->id_state == I2C_READY),
              "i2cStop(), #1",
              "invalid state");
  i2c_lld_stop(i2cp);
  i2cp->id_state = I2C_STOP;
  chSysUnlock();
}

/**
 * @brief     Generate (re)start on the bus.
 *
 * @param[in] i2cp           pointer to the @p I2CDriver object
 */
void i2cMasterStart(I2CDriver *i2cp){

  chDbgCheck((i2cp != NULL), "i2cMasterTransmit");

  chSysLock();
  i2c_lld_master_start(i2cp);
  chSysUnlock();
}

/**
 * @brief     Generate stop on the bus.
 *
 * @param[in] i2cp           pointer to the @p I2CDriver object
 */
void i2cMasterStop(I2CDriver *i2cp){

  chDbgCheck((i2cp != NULL), "i2cMasterTransmit");
  chSysLock();
  i2c_lld_master_stop(i2cp);
  chSysUnlock();
}

/**
 * @brief Sends data ever the I2C bus.
 *
 * @param[in] i2cp           pointer to the @p I2CDriver object
 * @param[in] i2cscfg        pointer to the @p I2CSlaveConfig object
 *
 */
void i2cMasterTransmit(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg) {

  chDbgCheck((i2cp != NULL) && (i2cscfg != NULL),
             "i2cMasterTransmit");
  chDbgAssert(i2cp->id_state == I2C_READY,
              "i2cMasterTransmit(), #1",
              "not active");

  chSysLock();
  i2c_lld_master_transmit(i2cp, i2cscfg);
  chSysUnlock();
}


/**
 * @brief Receives data from the I2C bus.
 *
 * @param[in] i2cp           pointer to the @p I2CDriver object
 * @param[in] i2cscfg        pointer to the @p I2CSlaveConfig object
 */
void i2cMasterReceive(I2CDriver *i2cp, I2CSlaveConfig *i2cscfg) {

  chDbgCheck((i2cp != NULL) && (i2cscfg != NULL),
             "i2cMasterReceive");
  chDbgAssert(i2cp->id_state == I2C_READY,
              "i2cMasterReceive(), #1",
              "not active");

  chSysLock();
  i2c_lld_master_receive(i2cp, i2cscfg);
  chSysUnlock();
}



#if I2C_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
/**
 * @brief   Gains exclusive access to the I2C bus.
 * @details This function tries to gain ownership to the I2C bus, if the bus
 *          is already being used then the invoking thread is queued.
 * @pre     In order to use this function the option @p I2C_USE_MUTUAL_EXCLUSION
 *          must be enabled.
 *
 * @param[in] i2cp      pointer to the @p I2CDriver object
 *
 * @api
 *
 */
void i2cAcquireBus(I2CDriver *i2cp) {

  chDbgCheck(i2cp != NULL, "i2cAcquireBus");

#if CH_USE_MUTEXES
  chMtxLock(&i2cp->id_mutex);
#elif CH_USE_SEMAPHORES
  chSemWait(&i2cp->id_semaphore);
#endif
}

/**
 * @brief   Releases exclusive access to the I2C bus.
 * @pre     In order to use this function the option @p I2C_USE_MUTUAL_EXCLUSION
 *          must be enabled.
 *
 * @param[in] i2cp      pointer to the @p I2CDriver object
 *
 * @api
 */
void i2cReleaseBus(I2CDriver *i2cp) {

  chDbgCheck(i2cp != NULL, "i2cReleaseBus");

#if CH_USE_MUTEXES
  (void)i2cp;
  chMtxUnlock();
#elif CH_USE_SEMAPHORES
  chSemSignal(&i2cp->id_semaphore);
#endif
}
#endif /* I2C_USE_MUTUAL_EXCLUSION */

#endif /* HAL_USE_I2C */

/** @} */