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/* ----------------------------------------------------------------------------

 *         ATMEL Microcontroller Software Support

 * ----------------------------------------------------------------------------

 * Copyright (c) 2008, Atmel Corporation

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 * - Redistributions of source code must retain the above copyright notice,

 * this list of conditions and the disclaimer below.

 *

 * Atmel's name may not be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * DISCLAIMER: 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

 * 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.

 * ----------------------------------------------------------------------------

 */

//------------------------------------------------------------------------------

//         Headers

//------------------------------------------------------------------------------

#include "spi.h"

//------------------------------------------------------------------------------

//         Exported functions

//------------------------------------------------------------------------------

//------------------------------------------------------------------------------

/// Enables a SPI peripheral

/// \param spi  Pointer to an AT91S_SPI instance.

//------------------------------------------------------------------------------

void SPI_Enable(AT91S_SPI *spi)

{

    spi->SPI_CR = AT91C_SPI_SPIEN;

}

//------------------------------------------------------------------------------

/// Disables a SPI peripheral.

/// \param spi  Pointer to an AT91S_SPI instance.

//------------------------------------------------------------------------------

void SPI_Disable(AT91S_SPI *spi)

{

    spi->SPI_CR = AT91C_SPI_SPIDIS;

}

//------------------------------------------------------------------------------

/// Configures a SPI peripheral as specified. The configuration can be computed

/// using several macros (see "SPI configuration macros") and the constants

/// defined in LibV3 (AT91C_SPI_*).

/// \param spi  Pointer to an AT91S_SPI instance.

/// \param id  Peripheral ID of the SPI.

/// \param configuration  Value of the SPI configuration register.

//------------------------------------------------------------------------------

void SPI_Configure(AT91S_SPI *spi,

                          unsigned int id,

                          unsigned int configuration)

{

    AT91C_BASE_PMC->PMC_PCER = 1 << id;

    spi->SPI_CR = AT91C_SPI_SPIDIS;

    // Execute a software reset of the SPI twice

    spi->SPI_CR = AT91C_SPI_SWRST;

    spi->SPI_CR = AT91C_SPI_SWRST;

    spi->SPI_MR = configuration;

}

//------------------------------------------------------------------------------

/// Configures a chip select of a SPI peripheral. The chip select configuration

/// is computed using the definition provided by the LibV3 (AT91C_SPI_*).

/// \param spi  Pointer to an AT91S_SPI instance.

/// \param npcs  Chip select to configure (1, 2, 3 or 4).

/// \param configuration  Desired chip select configuration.

//------------------------------------------------------------------------------

void SPI_ConfigureNPCS(AT91S_SPI *spi,

                              unsigned int npcs,

                              unsigned int configuration)

{

    spi->SPI_CSR[npcs] = configuration;

}

//------------------------------------------------------------------------------

/// Sends data through a SPI peripheral. If the SPI is configured to use a fixed

/// peripheral select, the npcs value is meaningless. Otherwise, it identifies

/// the component which shall be addressed.

/// \param spi  Pointer to an AT91S_SPI instance.

/// \param npcs  Chip select of the component to address (1, 2, 3 or 4).

/// \param data  Word of data to send.

//------------------------------------------------------------------------------

void SPI_Write(AT91S_SPI *spi, unsigned int npcs, unsigned short data)

{

    // Discard contents of RDR register

    //volatile unsigned int discard = spi->SPI_RDR;

    // Send data

    while ((spi->SPI_SR & AT91C_SPI_TXEMPTY) == 0);

    spi->SPI_TDR = data | SPI_PCS(npcs);

    while ((spi->SPI_SR & AT91C_SPI_TDRE) == 0);

}

//------------------------------------------------------------------------------

/// Sends the contents of buffer through a SPI peripheral, using the PDC to

/// take care of the transfer.

/// \param spi  Pointer to an AT91S_SPI instance.

/// \param buffer  Data buffer to send.

/// \param length  Length of the data buffer.

//------------------------------------------------------------------------------

unsigned char SPI_WriteBuffer(AT91S_SPI *spi,

                                     void *buffer,

                                     unsigned int length)

{

    // Check if first bank is free

    if (spi->SPI_TCR == 0) {

        spi->SPI_TPR = (unsigned int) buffer;

        spi->SPI_TCR = length;

        spi->SPI_PTCR = AT91C_PDC_TXTEN;

        return 1;

    }

    // Check if second bank is free

    else if (spi->SPI_TNCR == 0) {

        spi->SPI_TNPR = (unsigned int) buffer;

        spi->SPI_TNCR = length;

        return 1;

    }

    // No free banks

    return 0;

}

//------------------------------------------------------------------------------

/// Returns 1 if there is no pending write operation on the SPI; otherwise

/// returns 0.

/// \param pSpi  Pointer to an AT91S_SPI instance.

//------------------------------------------------------------------------------

unsigned char SPI_IsFinished(AT91S_SPI *pSpi)

{

    return ((pSpi->SPI_SR & AT91C_SPI_TXEMPTY) != 0);

}

//------------------------------------------------------------------------------

/// Reads and returns the last word of data received by a SPI peripheral. This

/// method must be called after a successful SPI_Write call.

/// \param spi  Pointer to an AT91S_SPI instance.

//------------------------------------------------------------------------------

unsigned short SPI_Read(AT91S_SPI *spi)

{

    while ((spi->SPI_SR & AT91C_SPI_RDRF) == 0);

    return spi->SPI_RDR & 0xFFFF;

}

//------------------------------------------------------------------------------

/// Reads data from a SPI peripheral until the provided buffer is filled. This

/// method does NOT need to be called after SPI_Write or SPI_WriteBuffer.

/// \param spi  Pointer to an AT91S_SPI instance.

/// \param buffer  Data buffer to store incoming bytes.

/// \param length  Length in bytes of the data buffer.

//------------------------------------------------------------------------------

unsigned char SPI_ReadBuffer(AT91S_SPI *spi,

                                    void *buffer,

                                    unsigned int length)

{

    // Check if the first bank is free

    if (spi->SPI_RCR == 0) {

        spi->SPI_RPR = (unsigned int) buffer;

        spi->SPI_RCR = length;

        spi->SPI_PTCR = AT91C_PDC_RXTEN;

        return 1;

    }

    // Check if second bank is free

    else if (spi->SPI_RNCR == 0) {

        spi->SPI_RNPR = (unsigned int) buffer;

        spi->SPI_RNCR = length;

        return 1;

    }

    // No free bank

    return 0;

}