eive-obsw/linux/spi/SpiCookie.h

#ifndef LINUX_SPI_SPICOOKIE_H_
#define LINUX_SPI_SPICOOKIE_H_

#include "spiDefinitions.h"
#include <fsfw/devicehandlers/CookieIF.h>
#include <linux/gpio/gpioDefinitions.h>
#include <linux/spi/spidev.h>

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 maxReplySize, spi::SpiMode 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::SpiMode spiMode, uint32_t spiSpeed);

    address_t getSpiAddress() const;
    std::string getSpiDevice() const;
    gpioId_t getChipSelectPin() const;
    size_t getMaxBufferSize() const;
    /**
     * 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::SpiMode& 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:
    size_t currentTransferSize = 0;

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

    const size_t maxSize;
    spi::SpiMode spiMode;
    uint32_t spiSpeed;
    bool halfDuplex = false;

    struct spi_ioc_transfer spiTransferStruct;
    UncommonParameters uncommonParameters;
};



#endif /* LINUX_SPI_SPICOOKIE_H_ */