Diff: drivers/SPI.h

Revision:

0:5b88d5760320

Child:

1:9db0e321a9f4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/drivers/SPI.h	Tue Dec 17 23:23:45 2019 +0000
@@ -0,0 +1,426 @@
+/* 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<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);
+
+    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<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
+
+    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<PlatformMutex> mutex;
+        /* Current user of the SPI */
+        SPI *owner;
+#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;
+
+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