ardupilot/libraries/AP_HAL/SPIDriver.h

#ifndef __AP_HAL_SPI_DRIVER_H__
#define __AP_HAL_SPI_DRIVER_H__

#include "AP_HAL_Namespace.h"


class AP_HAL::SPIDeviceManager {
public:
    virtual void init(void *) = 0;
    virtual AP_HAL::SPIDeviceDriver* device(enum AP_HAL::SPIDevice) = 0;
};

/**
 * We still need an abstraction for performing bulk
 * transfers to be portable to other platforms.
 */

class AP_HAL::SPIDeviceDriver {
public:
    virtual void init() = 0;
    virtual AP_HAL::Semaphore* get_semaphore() = 0;
    virtual void transaction(const uint8_t *tx, uint8_t *rx, uint16_t len) = 0;

    virtual void cs_assert() = 0;
    virtual void cs_release() = 0;
    virtual uint8_t transfer (uint8_t data) = 0;
    virtual void transfer (const uint8_t *data, uint16_t len) = 0;

    /**
       optional set_bus_speed() interface. This can be used by drivers
       to request higher speed for sensor registers once the sensor is
       initialised. This is used by the MPU6000 driver which can
       handle 20MHz for sensor register reads, but only 1MHz for other
       registers.
     */
    enum bus_speed {
        SPI_SPEED_LOW, SPI_SPEED_HIGH
    };

    virtual void set_bus_speed(enum bus_speed speed) {}
    
};

#endif // __AP_HAL_SPI_DRIVER_H__