/* mbed Microcontroller Library
* Copyright (c) 2006-2019 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 "rtos/Mutex.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/Callback.h"
#include "platform/Transaction.h"
#endif
namespace mbed {
/**
* \defgroup drivers_SPI SPI class
* \ingroup drivers-public-api-spi
* @{
*/
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
*/
class SPI : private NonCopyable<SPI> {
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);
/** 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 static_pinmap reference to structure which holds static pinmap.
*/
SPI(const spi_pinmap_t &static_pinmap);
SPI(const spi_pinmap_t &&) = delete; // prevent passing of temporary objects
/** 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 static_pinmap reference to structure which holds static pinmap.
* @param ssel SPI Chip Select pin.
*/
SPI(const spi_pinmap_t &static_pinmap, PinName ssel);
SPI(const spi_pinmap_t &&, PinName) = delete; // prevent passing of temporary objects
virtual ~SPI();
/** Configure the data transmission format.
*
* @param bits Number of bits per SPI frame (4 - 32, target dependent).
* @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<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(&_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
// All members of spi_peripheral_s must be initialized to make the structure
// constant-initialized, and hence able to be omitted by the linker,
// as SingletonPtr now relies on C++ constant-initialization. (Previously it
// worked through C++ zero-initialization). And all the constants should be zero
// to ensure it stays in the actual zero-init part of the image if used, avoiding
// an initialized-data cost.
struct spi_peripheral_s {
/* Internal SPI name identifying the resources. */
SPIName name = SPIName(0);
/* Internal SPI object handling the resources' state. */
spi_t spi{};
/* Used by lock and unlock for thread safety */
SingletonPtr<rtos::Mutex> mutex;
/* Current user of the SPI */
SPI *owner = nullptr;
#if DEVICE_SPI_ASYNCH && TRANSACTION_QUEUE_SIZE_SPI
/* Queue of pending transfers */
SingletonPtr<CircularBuffer<Transaction<SPI>, 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<SPI> _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;
/* Static pinmap data */
const spi_pinmap_t *_static_pinmap;
/* SPI peripheral name */
SPIName _peripheral_name;
/* Pointer to spi init function */
void (*_init_func)(SPI *);
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();
static void _do_init(SPI *obj);
static void _do_init_direct(SPI *obj);
#endif //!defined(DOXYGEN_ONLY)
};
/** @}*/
} // namespace mbed
#endif // DEVICE_SPI || DOXYGEN_ONLY
#endif // MBED_SPI_H
