/* mbed Microcontroller Library * Copyright (c) 2006-2015 ARM Limited * SPDX-License-Identifier: Apache-2.0 * * 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 DEVICE_SPI || defined(DOXYGEN_ONLY) #include "platform/PlatformMutex.h" #include "hal/spi_api.h" #include "drivers/DigitalOut.h" #include "platform/SingletonPtr.h" #include "platform/NonCopyable.h" #if defined MBED_CONF_DRIVERS_SPI_COUNT_MAX && DEVICE_SPI_COUNT > MBED_CONF_DRIVERS_SPI_COUNT_MAX #define SPI_PERIPHERALS_USED MBED_CONF_DRIVERS_SPI_COUNT_MAX #elif defined DEVICE_SPI_COUNT #define SPI_PERIPHERALS_USED DEVICE_SPI_COUNT #else /* Backwards compatibility with HALs not providing DEVICE_SPI_COUNT */ #define SPI_PERIPHERALS_USED 1 #endif #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 */ struct use_gpio_ssel_t { }; const use_gpio_ssel_t use_gpio_ssel; /** 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 of how to send a byte to a SPI slave and record the response: * @code * #include "mbed.h" * * SPI device(SPI_MOSI, SPI_MISO, SPI_SCLK) * * DigitalOut chip_select(SPI_CS); * * int main() { * device.lock(); * chip_select = 0; * * int response = device.write(0xFF); * * chip_select = 1; * device.unlock(); * } * @endcode * * Example using hardware Chip Select line: * @code * #include "mbed.h" * * SPI device(SPI_MOSI, SPI_MISO, SPI_SCLK, SPI_CS) * * int main() { * device.lock(); * int response = device.write(0xFF); * device.unlock(); * } * @endcode * @ingroup drivers */ class SPI : private NonCopyable { public: /** Create a SPI master connected to the specified pins. * * @note This constructor passes the SSEL pin selection to the target HAL. * Not all targets support SSEL, so this cannot be relied on in portable code. * Portable code should use the alternative constructor that uses GPIO * for SSEL. * * @note You can specify mosi or miso 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); /** Create a SPI master connected to the specified pins. * * @note This constructor manipulates the SSEL pin as a GPIO output * using a DigitalOut object. This should work on any target, and permits * the use of select() and deselect() methods to keep the pin asserted * between transfers. * * @note You can specify mosi or miso 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, use_gpio_ssel_t); virtual ~SPI(); /** 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 Clock 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. * * @return 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. * @return * 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); /** Assert the Slave Select line, acquiring exclusive access to this SPI bus. * * If use_gpio_ssel was not passed to the constructor, this only acquires * exclusive access; it cannot assert the Slave Select line. */ void select(void); /** Deassert the Slave Select line, releasing exclusive access to this SPI bus. */ void deselect(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 during a 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 transferred. 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 event mask of events to modify. @see spi_api.h for SPI events. * * @return Operation result. * @retval 0 If the transfer has started. * @retval -1 If SPI peripheral is busy. */ template 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(&_peripheral->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 transfers in the queue, if any. */ void abort_transfer(); /** Clear the queue of transfers. */ void clear_transfer_buffer(); /** Clear the queue of transfers and abort the on-going transfer. */ void abort_all_transfers(); /** Configure DMA usage suggestion for non-blocking transfers. * * @param usage The usage DMA hint for peripheral. * * @return Result of the operation. * @retval 0 The usage was set. * @retval -1 Usage cannot be set as there is an ongoing transaction. */ int set_dma_usage(DMAUsage usage); #if !defined(DOXYGEN_ONLY) protected: /** SPI interrupt handler. */ void irq_handler_asynch(void); /** Start the transfer or put it on the queue. * * @param tx_buffer The TX buffer with data to be transferred. 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 in bits. * @param callback The event callback function. * @param event The event mask of events to modify. * * @return Operation success. * @retval 0 A transfer was started or added to the queue. * @retval -1 Transfer can't be added because queue 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); /** Put a transfer on the transfer queue. * * @param tx_buffer The TX buffer with data to be transferred. 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 in bits. * @param callback The event callback function. * @param event The event mask of events to modify. * * @return Operation success. * @retval 0 A transfer was added to the queue. * @retval -1 Transfer can't be added because 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); /** Configure a callback, SPI peripheral, and initiate a new transfer. * * @param tx_buffer The TX buffer with data to be transferred. 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 event mask 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 and start the transfer if there was one pending. */ void dequeue_transaction(); #endif // TRANSACTION_QUEUE_SIZE_SPI #endif // !defined(DOXYGEN_ONLY) #endif // DEVICE_SPI_ASYNCH #if !defined(DOXYGEN_ONLY) protected: #ifdef DEVICE_SPI_COUNT // HAL must have defined this as a global enum typedef ::SPIName SPIName; #else // HAL may or may not have defined it - use a local definition enum SPIName { GlobalSPI }; #endif struct spi_peripheral_s { /* Internal SPI name identifying the resources. */ SPIName name; /* Internal SPI object handling the resources' state. */ spi_t spi; /* Used by lock and unlock for thread safety */ SingletonPtr mutex; /* Current user of the SPI */ SPI *owner; #if DEVICE_SPI_ASYNCH && TRANSACTION_QUEUE_SIZE_SPI /* Queue of pending transfers */ SingletonPtr, TRANSACTION_QUEUE_SIZE_SPI> > transaction_buffer; #endif }; // holds spi_peripheral_s per peripheral on the device. // Drawback: it costs ram size even if the device is not used, however // application can limit the allocation via JSON. static spi_peripheral_s _peripherals[SPI_PERIPHERALS_USED]; static int _peripherals_used; // Holds the reference to the associated peripheral. spi_peripheral_s *_peripheral; #if DEVICE_SPI_ASYNCH /* Interrupt */ CThunk _irq; /* Interrupt handler callback */ event_callback_t _callback; /* Current preferred DMA mode @see dma_api.h */ DMAUsage _usage; /* Current sate of the sleep manager */ bool _deep_sleep_locked; #endif // DEVICE_SPI_ASYNCH // Configuration. PinName _mosi; PinName _miso; PinName _sclk; PinName _hw_ssel; // The Slave Select GPIO if we're doing it ourselves. DigitalOut _sw_ssel; /* Size of the SPI frame */ int _bits; /* Clock polairy and phase */ int _mode; /* Clock frequency */ int _hz; /* Default character used for NULL transfers */ char _write_fill; /* Select count to handle re-entrant selection */ int8_t _select_count; private: void _do_construct(); /** Private acquire function without locking/unlocking. * Implemented in order to avoid duplicate locking and boost performance. */ void _acquire(void); void _set_ssel(int); /** Private lookup in the static _peripherals table. */ static spi_peripheral_s *_lookup(SPIName name); /** Allocate an entry in the static _peripherals table. */ static spi_peripheral_s *_alloc(); #endif //!defined(DOXYGEN_ONLY) }; } // namespace mbed #endif // DEVICE_SPI || DOXYGEN_ONLY #endif // MBED_SPI_H