Diff: mbed-os/drivers/SPI.h

Revision:

0:9fca2b23d0ba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/drivers/SPI.h	Sat Feb 23 12:13:36 2019 +0000
@@ -0,0 +1,298 @@
+/* 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 specfied 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 recieved 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 occured
+     * 
+     * @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);
+
+#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;
+#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