/**
 * \file *********************************************************************
 *
 * \brief
 *      XMEGA TWI slave driver source file.
 *
 *      This file contains the function implementations the XMEGA TWI slave
 *      driver.
 *
 *      The driver is not intended for size and/or speed critical code, since
 *      most functions are just a few lines of code, and the function call
 *      overhead would decrease code performance. The driver is intended for
 *      rapid prototyping and documentation purposes for getting started with
 *      the XMEGA TWI slave module.
 *
 *      For size and/or speed critical code, it is recommended to copy the
 *      function contents directly into your application instead of making
 *      a function call.
 *
 *      Several functions use the following construct:
 *          "some_register = ... | (some_parameter ? SOME_BIT_bm : 0) | ..."
 *      Although the use of the ternary operator ( if ? then : else ) is
 *      discouraged, in some occasions the operator makes it possible to write
 *      pretty clean and neat code. In this driver, the construct is used to
 *      set or not set a configuration bit based on a boolean input parameter,
 *      such as the "some_parameter" in the example above.
 *
 * \par Application note:
 *      AVR1308: Using the XMEGA TWI
 *
 * \par Documentation
 *      For comprehensive code documentation, supported compilers, compiler
 *      settings and supported devices see readme.html
 *
 *      Atmel Corporation: http://www.atmel.com \n
 *
 * $Revision: 2660 $
 * $Date: 2009-08-11 12:28:58 +0200 (Tue, 11 Aug 2009) $  \n
 *
 * Copyright (c) 2008 Atmel Corporation. All rights reserved.
 *
 * \asf_license_start
 *
 * \page License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. The name of Atmel may not be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 4. This software may only be redistributed and used in connection with an
 *    Atmel microcontroller product.
 *
 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * \asf_license_stop
 *
 *****************************************************************************/

#include "twis.h"


/*! \brief Initalizes TWI slave driver structure.
 *
 *  Initialize the instance of the TWI Slave and set the appropriate values.
 *
 *  \param twi                  The TWI_Slave_t struct instance.
 *  \param module               Pointer to the TWI module.
 *  \param processDataFunction  Pointer to the function that handles incoming data.
 */
void TWI_SlaveInitializeDriver(TWI_Slave_t * twi,
    TWI_t * module,
    void (*processDataFunction) (void))
{
    twi->interface = module;
    twi->Process_Data = processDataFunction;
    twi->bytesReceived = 0;
    twi->bytesSent = 0;
    twi->status = TWIS_STATUS_READY;
    twi->result = TWIS_RESULT_UNKNOWN;
    twi->abort = false;
}


/*! \brief Initialize the TWI module.
 *
 *  Enables interrupts on address recognition and data available.
 *  Remember to enable interrupts globally from the main application.
 *
 *  \param twi        The TWI_Slave_t struct instance.
 *  \param address    Slave address for this module.
 *  \param intLevel   Interrupt level for the TWI slave interrupt handler.
 */
void TWI_SlaveInitializeModule(TWI_Slave_t * twi,
    uint8_t address,
    TWI_SLAVE_INTLVL_t intLevel)
{
    twi->interface->SLAVE.CTRLA =
        intLevel | TWI_SLAVE_DIEN_bm | TWI_SLAVE_APIEN_bm |
        TWI_SLAVE_ENABLE_bm;
    twi->interface->SLAVE.ADDR = (address << 1);
}


/*! \brief Common TWI slave interrupt service routine.
 *
 *  Handles all TWI transactions and responses to address match, data reception,
 *  data transmission, bus error and data collision.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveInterruptHandler(TWI_Slave_t * twi)
{
    uint8_t currentStatus = twi->interface->SLAVE.STATUS;

    /* If bus error. */
    if (currentStatus & TWI_SLAVE_BUSERR_bm) {
        twi->bytesReceived = 0;
        twi->bytesSent = 0;
        twi->result = TWIS_RESULT_BUS_ERROR;
        twi->status = TWIS_STATUS_READY;
    }

    /* If transmit collision. */
    else if (currentStatus & TWI_SLAVE_COLL_bm) {
        twi->bytesReceived = 0;
        twi->bytesSent = 0;
        twi->result = TWIS_RESULT_TRANSMIT_COLLISION;
        twi->status = TWIS_STATUS_READY;
    }

    /* If address match. */
    else if ((currentStatus & TWI_SLAVE_APIF_bm) &&
        (currentStatus & TWI_SLAVE_AP_bm)) {

        TWI_SlaveAddressMatchHandler(twi);
    }

    /* If stop (only enabled through slave read transaction). */
    else if (currentStatus & TWI_SLAVE_APIF_bm) {
        TWI_SlaveStopHandler(twi);
    }

    /* If data interrupt. */
    else if (currentStatus & TWI_SLAVE_DIF_bm) {
        TWI_SlaveDataHandler(twi);
    }

    /* If unexpected state. */
    else {
        TWI_SlaveTransactionFinished(twi, TWIS_RESULT_FAIL);
    }
}

/*! \brief TWI address match interrupt handler.
 *
 *  Prepares TWI module for transaction when an address match occurs.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveAddressMatchHandler(TWI_Slave_t * twi)
{
    /* If application signalling need to abort (error occured). */
    if (twi->abort) {
        twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
        TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
        twi->abort = false;
    } else {
        twi->status = TWIS_STATUS_BUSY;
        twi->result = TWIS_RESULT_UNKNOWN;

        /* Disable stop interrupt. */
        uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
        twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;

        twi->bytesReceived = 0;
        twi->bytesSent = 0;

        /* Send ACK, wait for data interrupt. */
        twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
    }
}


/*! \brief TWI stop condition interrupt handler.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveStopHandler(TWI_Slave_t * twi)
{
    /* Disable stop interrupt. */
    uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
    twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;

    /* Clear APIF, according to flowchart don't ACK or NACK */
    uint8_t currentStatus = twi->interface->SLAVE.STATUS;
    twi->interface->SLAVE.STATUS = currentStatus | TWI_SLAVE_APIF_bm;

    TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);

}


/*! \brief TWI data interrupt handler.
 *
 *  Calls the appropriate slave read or write handler.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveDataHandler(TWI_Slave_t * twi)
{
    if (twi->interface->SLAVE.STATUS & TWI_SLAVE_DIR_bm) {
        TWI_SlaveWriteHandler(twi);
    } else {
        TWI_SlaveReadHandler(twi);
    }
}


/*! \brief TWI slave read interrupt handler.
 *
 *  Handles TWI slave read transactions and responses.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveReadHandler(TWI_Slave_t * twi)
{
    /* Enable stop interrupt. */
    uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
    twi->interface->SLAVE.CTRLA = currentCtrlA | TWI_SLAVE_PIEN_bm;

    /* If free space in buffer. */
    if (twi->bytesReceived < TWIS_RECEIVE_BUFFER_SIZE) {
        /* Fetch data */
        uint8_t data = twi->interface->SLAVE.DATA;
        twi->receivedData[twi->bytesReceived] = data;

        /* Process data. */
        twi->Process_Data();

        twi->bytesReceived++;

        /* If application signalling need to abort (error occured),
         * complete transaction and wait for next START. Otherwise
         * send ACK and wait for data interrupt.
         */
        if (twi->abort) {
            twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
            TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
            twi->abort = false;
        } else {
            twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
        }
    }
    /* If buffer overflow, send NACK and wait for next START. Set
     * result buffer overflow.
     */
    else {
        twi->interface->SLAVE.CTRLB =
            TWI_SLAVE_ACKACT_bm | TWI_SLAVE_CMD_COMPTRANS_gc;
        TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
    }
}


/*! \brief TWI slave write interrupt handler.
 *
 *  Handles TWI slave write transactions and responses.
 *
 *  \param twi The TWI_Slave_t struct instance.
 */
void TWI_SlaveWriteHandler(TWI_Slave_t * twi)
{
    /* If NACK, slave write transaction finished. */
    if ((twi->bytesSent > 0) &&
        (twi->interface->SLAVE.STATUS & TWI_SLAVE_RXACK_bm)) {

        twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
        TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
    }
    /* If ACK, master expects more data. */
    else {
        if (twi->bytesSent < TWIS_SEND_BUFFER_SIZE) {
            uint8_t data = twi->sendData[twi->bytesSent];
            twi->interface->SLAVE.DATA = data;
            twi->bytesSent++;

            /* Send data, wait for data interrupt. */
            twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
        }
        /* If buffer overflow. */
        else {
            twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
            TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
        }
    }
}


/*! \brief TWI transaction finished function.
 *
 *  Prepares module for new transaction.
 *
 *  \param twi    The TWI_Slave_t struct instance.
 *  \param result The result of the transaction.
 */
void TWI_SlaveTransactionFinished(TWI_Slave_t * twi,
    uint8_t result)
{
    twi->result = result;
    twi->status = TWIS_STATUS_READY;
}