fsfw/hal/src/fsfw_hal/linux/spi/SpiCookie.h

#ifndef LINUX_SPI_SPICOOKIE_H_
#define LINUX_SPI_SPICOOKIE_H_

#include "spiDefinitions.h"
#include "../../common/gpio/gpioDefinitions.h"

#include <fsfw/devicehandlers/CookieIF.h>

#include <linux/spi/spidev.h>

/**
 * @brief   This cookie class is passed to the SPI communication interface
 * @details
 * This cookie contains device specific properties like speed and SPI mode or the SPI transfer
 * struct required by the Linux SPI driver. It also contains a handle to a GPIO interface
 * to perform slave select switching when necessary.
 *
 * The user can specify gpio::NO_GPIO as the GPIO ID or use a custom send callback to meet
 * special requirements like expander slave select switching (e.g. GPIO or I2C expander)
 * or special timing related requirements.
 */
class SpiCookie: public CookieIF {
public:
    /**
     * Each SPI device will have a corresponding cookie. The cookie is used by the communication
     * interface and contains device specific information like the largest expected size to be
     * sent and received and the GPIO pin used to toggle the SPI slave select pin.
     * @param spiAddress
     * @param chipSelect    Chip select. gpio::NO_GPIO can be used for hardware slave selects.
     * @param spiDev
     * @param maxSize
     */
    SpiCookie(address_t spiAddress, gpioId_t chipSelect, std::string spiDev,
            const size_t maxSize, spi::SpiModes spiMode, uint32_t spiSpeed);

    /**
     * Like constructor above, but without a dedicated GPIO CS. Can be used for hardware
     * slave select or if CS logic is performed with decoders.
     */
    SpiCookie(address_t spiAddress, std::string spiDev, const size_t maxReplySize,
            spi::SpiModes spiMode, uint32_t spiSpeed);

    /**
     * Use the callback mode of the SPI communication interface. The user can pass the callback
     * function here or by using the setter function #setCallbackMode
     */
    SpiCookie(address_t spiAddress, gpioId_t chipSelect, std::string spiDev, const size_t maxSize,
            spi::SpiModes spiMode, uint32_t spiSpeed, spi::send_callback_function_t callback,
            void *args);

    /**
     * Get the callback function
     * @param callback
     * @param args
     */
    void getCallback(spi::send_callback_function_t* callback, void** args);

    address_t getSpiAddress() const;
    std::string getSpiDevice() const;
    gpioId_t getChipSelectPin() const;
    size_t getMaxBufferSize() const;

    spi::SpiComIfModes getComIfMode() const;

    /** Enables changing SPI speed at run-time */
    void setSpiSpeed(uint32_t newSpeed);
    /** Enables changing the SPI mode at run-time */
    void setSpiMode(spi::SpiModes newMode);

    /**
     * Set the SPI to callback mode and assigns the user supplied callback and an argument
     * passed to the callback.
     * @param callback
     * @param args
     */
    void setCallbackMode(spi::send_callback_function_t callback, void* args);

    /**
	 * Can be used to set the callback arguments and a later point than initialization.
	 * @param args
	 */
	void setCallbackArgs(void* args);

    /**
     * True if SPI transfers should be performed in full duplex mode
     * @return
     */
    bool isFullDuplex() const;

    /**
     * Set transfer type to full duplex or half duplex. Full duplex is the default setting,
     * ressembling common SPI hardware implementation with shift registers, where read and writes
     * happen simultaneosly.
     * @param fullDuplex
     */
    void setFullOrHalfDuplex(bool halfDuplex);

    /**
     * This needs to be called to specify where the SPI driver writes to or reads from.
     * @param readLocation
     * @param writeLocation
     */
    void assignReadBuffer(uint8_t* rx);
    void assignWriteBuffer(const uint8_t* tx);
    /**
     * Assign size for the next transfer.
     * @param transferSize
     */
    void assignTransferSize(size_t transferSize);
    size_t getCurrentTransferSize() const;

    struct UncommonParameters {
        uint8_t bitsPerWord = 8;
        bool noCs = false;
        bool csHigh = false;
        bool threeWireSpi = false;
        /* MSB first is more common */
        bool lsbFirst = false;
    };

    /**
     * Can be used to explicitely disable hardware chip select.
     * Some drivers like the Raspberry Pi Linux driver will not use hardware chip select by default
     * (see https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md)
     * @param enable
     */
    void setNoCs(bool enable);
    void setThreeWireSpi(bool enable);
    void setLsbFirst(bool enable);
    void setCsHigh(bool enable);
    void setBitsPerWord(uint8_t bitsPerWord);

    void getSpiParameters(spi::SpiModes& spiMode, uint32_t& spiSpeed,
            UncommonParameters* parameters = nullptr) const;

    /**
     * See spidev.h cs_change and delay_usecs
     * @param deselectCs
     * @param delayUsecs
     */
    void activateCsDeselect(bool deselectCs, uint16_t delayUsecs);

    spi_ioc_transfer* getTransferStructHandle();
private:

    /**
     * Internal constructor which initializes every field
     * @param spiAddress
     * @param chipSelect
     * @param spiDev
     * @param maxSize
     * @param spiMode
     * @param spiSpeed
     * @param callback
     * @param args
     */
    SpiCookie(spi::SpiComIfModes comIfMode, address_t spiAddress, gpioId_t chipSelect,
            std::string spiDev, const size_t maxSize, spi::SpiModes spiMode, uint32_t spiSpeed,
            spi::send_callback_function_t callback, void* args);

    size_t currentTransferSize = 0;

    address_t spiAddress;
    gpioId_t chipSelectPin;
    std::string spiDevice;

    spi::SpiComIfModes comIfMode;

    // Required for regular mode
    const size_t maxSize;
    spi::SpiModes spiMode;
    uint32_t spiSpeed;
    bool halfDuplex = false;

    // Required for callback mode
    spi::send_callback_function_t sendCallback = nullptr;
    void* callbackArgs = nullptr;

    struct spi_ioc_transfer spiTransferStruct = {};
    UncommonParameters uncommonParameters;
};



#endif /* LINUX_SPI_SPICOOKIE_H_ */