Add SPI interface

include/sta/spi_interface.hpp

@@ -0,0 +1,87 @@
+#ifndef STA_SPI_INTERFACE_HPP
+#define STA_SPI_INTERFACE_HPP
+
+#include <sta/mutex.hpp>
+
+#include <stdint.h>
+#include <stddef.h>
+
+
+namespace sta
+{
+	/**
+	 * @brief Interface for SPI hardware.
+	 */
+	class SpiInterface
+	{
+	public:
+		/**
+		 * @param mutex     Mutex object for managing shared access. Pass nullptr for no access control
+		 */
+		SpiInterface(Mutex * mutex = nullptr);
+
+
+		/**
+		 * @brief Send single byte of data.
+		 *
+		 * @param value     8-bit value
+		 */
+		virtual void transfer(uint8_t value) = 0;
+		/**
+		 * @brief Send data from buffer.
+		 *
+		 * @param buffer    Source buffer
+		 * @param size      Number of bytes in buffer
+		 */
+		virtual void transfer(const uint8_t * buffer, size_t size) = 0;
+
+		/**
+		 * @brief Send two bytes of data.
+		 *
+		 * @param value     16-bit value
+		 */
+		virtual void transfer16(uint16_t value) = 0;
+
+		/**
+		 * @brief Send byte value repeatedly.
+		 *
+		 * @param value     8-bit value to repeat
+		 * @param count     Number of repetitions
+		 */
+		virtual void fill(uint8_t value, size_t count) = 0;
+		/**
+		 * @brief Send 32-bit value repeatedly.
+		 *
+		 * @param value     32-bit value to repeat
+		 * @param count     Number of repetitions
+		 */
+		virtual void fill32(uint32_t value, size_t count) = 0;
+
+		/**
+		 * @brief Read incoming data to buffer.
+		 *
+		 * @param buffer    Destination buffer
+		 * @param size      Number of bytes to read
+		 */
+		virtual void receive(uint8_t * buffer, size_t size) = 0;
+
+		/**
+		 * @brief Acquire usage rights to use the interface.
+		 *
+		 * Must be called before any I/O operations are executed.
+		 */
+		virtual void acquire();
+		/**
+		 * @brief Release usage rights for interface.
+		 *
+		 * Must be called after last I/O operation.
+		 */
+		virtual void release();
+
+	private:
+		Mutex * mutex_;	/**< Mutex object */
+	};
+} // namespace sta
+
+
+#endif // STA_SPI_INTERFACE_HPP

src/spi_interface.cpp

@@ -0,0 +1,21 @@
+#include <sta/spi_interface.hpp>
+
+
+namespace sta
+{
+	SpiInterface::SpiInterface(Mutex * mutex /* = nullptr */)
+		: mutex_{mutex}
+	{}
+
+	void SpiInterface::acquire()
+	{
+		if (mutex_ != nullptr)
+			mutex_->acquire();
+	}
+
+	void SpiInterface::release()
+	{
+		if (mutex_ != nullptr)
+			mutex_->release();
+	}
+} // namespace sta