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/* mbed Microcontroller Library

 * Copyright (c) 2006-2015 ARM Limited

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#ifndef MBED_SPI_H

#define MBED_SPI_H



#include "platform/platform.h"



#if defined (DEVICE_SPI) || defined(DOXYGEN_ONLY)



#include "platform/PlatformMutex.h"

#include "hal/spi_api.h"

#include "platform/SingletonPtr.h"

#include "platform/NonCopyable.h"



#if DEVICE_SPI_ASYNCH

#include "platform/CThunk.h"

#include "hal/dma_api.h"

#include "platform/CircularBuffer.h"

#include "platform/FunctionPointer.h"

#include "platform/Transaction.h"

#endif



namespace mbed {

/** \addtogroup drivers */



/** A SPI Master, used for communicating with SPI slave devices

 *

 * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz

 *

 * Most SPI devices will also require Chip Select and Reset signals. These

 * can be controlled using DigitalOut pins

 *

 * @note Synchronization level: Thread safe

 *

 * Example:

 * @code

 * // Send a byte to a SPI slave, and record the response

 *

 * #include "mbed.h"

 *

 * // hardware ssel (where applicable)

 * //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel

 *

 * // software ssel

 * SPI device(p5, p6, p7); // mosi, miso, sclk

 * DigitalOut cs(p8); // ssel

 *

 * int main() {

 *     // hardware ssel (where applicable)

 *     //int response = device.write(0xFF);

 *

 *     device.lock();

 *     // software ssel

 *     cs = 0;

 *     int response = device.write(0xFF);

 *     cs = 1;

 *     device.unlock();

 *

 * }

 * @endcode

 * @ingroup drivers

 */

class SPI : private NonCopyable<SPI> {



public:



    /** Create a SPI master connected to the specified pins

     *

     *  mosi or miso can be specified as NC if not used

     *

     *  @param mosi SPI Master Out, Slave In pin

     *  @param miso SPI Master In, Slave Out pin

     *  @param sclk SPI Clock pin

     *  @param ssel SPI chip select pin

     */

    SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel = NC);



    /** Configure the data transmission format

     *

     *  @param bits Number of bits per SPI frame (4 - 16)

     *  @param mode Clock polarity and phase mode (0 - 3)

     *

     * @code

     * mode | POL PHA

     * -----+--------

     *   0  |  0   0

     *   1  |  0   1

     *   2  |  1   0

     *   3  |  1   1

     * @endcode

     */

    void format(int bits, int mode = 0);



    /** Set the spi bus clock frequency

     *

     *  @param hz SCLK frequency in hz (default = 1MHz)

     */

    void frequency(int hz = 1000000);



    /** Write to the SPI Slave and return the response

     *

     *  @param value Data to be sent to the SPI slave

     *

     *  @returns

     *    Response from the SPI slave

     */

    virtual int write(int value);



    /** Write to the SPI Slave and obtain the response

     *

     *  The total number of bytes sent and received will be the maximum of

     *  tx_length and rx_length. The bytes written will be padded with the

     *  value 0xff.

     *

     *  @param tx_buffer Pointer to the byte-array of data to write to the device

     *  @param tx_length Number of bytes to write, may be zero

     *  @param rx_buffer Pointer to the byte-array of data to read from the device

     *  @param rx_length Number of bytes to read, may be zero

     *  @returns

     *      The number of bytes written and read from the device. This is

     *      maximum of tx_length and rx_length.

     */

    virtual int write(const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length);



    /** Acquire exclusive access to this SPI bus

     */

    virtual void lock(void);



    /** Release exclusive access to this SPI bus

     */

    virtual void unlock(void);



    /** Set default write data

      * SPI requires the master to send some data during a read operation.

      * Different devices may require different default byte values.

      * For example: A SD Card requires default bytes to be 0xFF.

      *

      * @param data    Default character to be transmitted while read operation

      */

    void set_default_write_value(char data);



#if DEVICE_SPI_ASYNCH



    /** Start non-blocking SPI transfer using 8bit buffers.

     *

     * This function locks the deep sleep until any event has occurred

     *

     * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,

     *                  the default SPI value is sent

     * @param tx_length The length of TX buffer in bytes

     * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,

     *                  received data are ignored

     * @param rx_length The length of RX buffer in bytes

     * @param callback  The event callback function

     * @param event     The logical OR of events to modify. Look at spi hal header file for SPI events.

     * @return Zero if the transfer has started, or -1 if SPI peripheral is busy

     */

    template<typename Type>

    int transfer(const Type *tx_buffer, int tx_length, Type *rx_buffer, int rx_length, const event_callback_t &callback, int event = SPI_EVENT_COMPLETE)

    {

        if (spi_active(&_spi)) {

            return queue_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type) * 8, callback, event);

        }

        start_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type) * 8, callback, event);

        return 0;

    }



    /** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.

     */

    void abort_transfer();



    /** Clear the transaction buffer

     */

    void clear_transfer_buffer();



    /** Clear the transaction buffer and abort on-going transfer.

     */

    void abort_all_transfers();



    /** Configure DMA usage suggestion for non-blocking transfers

     *

     *  @param usage The usage DMA hint for peripheral

     *  @return Zero if the usage was set, -1 if a transaction is on-going

    */

    int set_dma_usage(DMAUsage usage);



protected:

    /** SPI IRQ handler

     *

    */

    void irq_handler_asynch(void);



    /** Common transfer method

     *

     * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,

     *                  the default SPI value is sent

     * @param tx_length The length of TX buffer in bytes

     * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,

     *                  received data are ignored

     * @param rx_length The length of RX buffer in bytes

     * @param bit_width The buffers element width

     * @param callback  The event callback function

     * @param event     The logical OR of events to modify

     * @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full

    */

    int transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event);



    /**

     *

     * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,

     *                  the default SPI value is sent

     * @param tx_length The length of TX buffer in bytes

     * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,

     *                  received data are ignored

     * @param rx_length The length of RX buffer in bytes

     * @param bit_width The buffers element width

     * @param callback  The event callback function

     * @param event     The logical OR of events to modify

     * @return Zero if a transfer was added to the queue, or -1 if the queue is full

    */

    int queue_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event);



    /** Configures a callback, spi peripheral and initiate a new transfer

     *

     * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,

     *                  the default SPI value is sent

     * @param tx_length The length of TX buffer in bytes

     * @param rx_buffer The RX buffer which is used for received data. If NULL is passed,

     *                  received data are ignored

     * @param rx_length The length of RX buffer in bytes

     * @param bit_width The buffers element width

     * @param callback  The event callback function

     * @param event     The logical OR of events to modify

    */

    void start_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event);



private:

    /** Lock deep sleep only if it is not yet locked */

    void lock_deep_sleep();



    /** Unlock deep sleep in case it is locked */

    void unlock_deep_sleep();





#if TRANSACTION_QUEUE_SIZE_SPI



    /** Start a new transaction

     *

     *  @param data Transaction data

    */

    void start_transaction(transaction_t *data);



    /** Dequeue a transaction

     *

    */

    void dequeue_transaction();

    static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;

#endif



#endif



public:

    virtual ~SPI()

    {

    }



protected:

    spi_t _spi;



#if DEVICE_SPI_ASYNCH

    CThunk<SPI> _irq;

    event_callback_t _callback;

    DMAUsage _usage;

    bool _deep_sleep_locked;

#endif



    void aquire(void);

    static SPI *_owner;

    static SingletonPtr<PlatformMutex> _mutex;

    int _bits;

    int _mode;

    int _hz;

    char _write_fill;



private:

    /* Private acquire function without locking/unlocking

     * Implemented in order to avoid duplicate locking and boost performance

     */

    void _acquire(void);

};



} // namespace mbed



#endif



#endif