File content as of revision 7:4dbae381f693:

/*!
 ******************************************************************************
 * @file:   adi_sense_spi.cpp
 * @brief:  ADI Sense OS-dependent wrapper layer for SPI interface
 *-----------------------------------------------------------------------------
 */

/******************************************************************************
 Copyright (c) 2017 Emutex Ltd. / Analog Devices, Inc.

 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 following disclaimer.
 - 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.
 - Modified versions of the software must be conspicuously marked as such.
 - This software is licensed solely and exclusively for use with processors
 manufactured by or for Analog Devices, Inc.
 - This software may not be combined or merged with other code in any manner
 that would cause the software to become subject to terms and conditions
 which differ from those listed here.
 - Neither the name of Analog Devices, Inc. nor the names of its
 contributors may be used to endorse or promote products derived
 from this software without specific prior written permission.
 - The use of this software may or may not infringe the patent rights of one
 or more patent holders.  This license does not release you from the
 requirement that you obtain separate licenses from these patent holders
 to use this software.

 THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES, INC. AND CONTRIBUTORS "AS IS" AND ANY
 EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
 TITLE, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
 NO EVENT SHALL ANALOG DEVICES, INC. OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, DAMAGES ARISING OUT OF CLAIMS OF INTELLECTUAL
 PROPERTY RIGHTS INFRINGEMENT; 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.
 *
 *****************************************************************************/

#include <mbed.h>

#include "inc/adi_sense_spi.h"
#include "inc/adi_sense_log.h"

#define ADI_SENSE_SPI_MODE       0 /* CPOL=0, CPHA=0 */
#define ADI_SENSE_SPI_FRAME_SIZE 8 /* 8-bit frame size */

class SpiContext
{
public:
    SpiContext(
        PinName mosiPin,
        PinName misoPin,
        PinName sckPin,
        PinName csPin,
        unsigned maxSpeed);

    int transfer(
        void *pTxData,
        void *pRxData,
        unsigned nLength,
        bool bCsHold);

private:
    SPI _spi;
    DigitalOut _cs;

    event_callback_t _callback;
    volatile int     _cbEvent;
    volatile bool    _cbFired;

    void _cbHandler(
        int event);

    int _waitForCallback(
        void);
};

SpiContext::SpiContext(PinName mosiPin,
                       PinName misoPin,
                       PinName sckPin,
                       PinName csPin,
                       unsigned maxSpeed)
    : _spi(mosiPin, misoPin, sckPin),
      _cs(csPin, 1)
{
    _cbEvent = 0;
    _cbFired = false;
    _callback.attach(this, &SpiContext::_cbHandler);

    _spi.format(ADI_SENSE_SPI_FRAME_SIZE, ADI_SENSE_SPI_MODE);
    _spi.frequency(maxSpeed);
}

void SpiContext::_cbHandler(int event)
{
    _cbEvent = event;
    _cbFired = true;
}

int SpiContext::_waitForCallback(void)
{
    int rc = 0;

    while ((_cbFired != true) && (_cbEvent != SPI_EVENT_COMPLETE))
    { ; }

    _cbFired = false;
    _cbEvent = 0;

    return rc;
}

int SpiContext::transfer(
    void *pTxData,
    void *pRxData,
    unsigned nLength,
    bool bCsHold)
{
    int rc = 0;

    _cs = 0;

    rc  = _spi.transfer((uint8_t *)pTxData, nLength,
                        (uint8_t *)pRxData, nLength,
                        _callback, SPI_EVENT_COMPLETE);
    if (rc < 0)
    {
        _cs = 1;
        return rc;
    }   

    rc = _waitForCallback();
    if ((rc < 0) || !bCsHold)
        _cs = 1;

    return rc;
}

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Open the SPI interface and allocate resources
 */
ADI_SENSE_RESULT adi_sense_SpiOpen(
    ADI_SENSE_PLATFORM_SPI_CONFIG *pConfig,
    ADI_SENSE_SPI_HANDLE *phDevice)
{
    SpiContext *pCtx = new SpiContext((PinName)pConfig->mosiPin,
                                      (PinName)pConfig->misoPin,
                                      (PinName)pConfig->sckPin,
                                      (PinName)pConfig->csPin,
                                      pConfig->maxSpeedHz);
    if (!pCtx)
    {
        ADI_SENSE_LOG_ERROR("Failed to allocate memory for SPI interface");
        return ADI_SENSE_NO_MEM;
    }

    *phDevice = reinterpret_cast<ADI_SENSE_SPI_HANDLE>(pCtx);
    return ADI_SENSE_SUCCESS;
}

/*
 * Execute a bi-directional data transfer on the SPI interface
 */
ADI_SENSE_RESULT
adi_sense_SpiTransfer(
    ADI_SENSE_SPI_HANDLE hDevice,
    void *pTxData,
    void *pRxData,
    unsigned nLength,
    bool bCsHold)
{
    SpiContext *pCtx = reinterpret_cast<SpiContext *>(hDevice);

    if (pCtx->transfer(pTxData, pRxData, nLength, bCsHold) < 0)
    {
        ADI_SENSE_LOG_ERROR("Failed to complete SPI transfer");
        return ADI_SENSE_FAILURE;
    }

    return ADI_SENSE_SUCCESS;
}

/*
 * Close the SPI interface and free resources
 */
void adi_sense_SpiClose(
    ADI_SENSE_SPI_HANDLE hDevice)
{
    SpiContext *pCtx = reinterpret_cast<SpiContext *>(hDevice);

    delete pCtx;
}

#ifdef __cplusplus
}
#endif

/*!
 * @}
 */