Spi.h

/*
MIT License

Copyright (c) 2020 Jeremiah Rose

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#pragma once

#include <stddef.h>
#include <linux/spi/spidev.h>

class Spi {
public:
        /* Enum SPI Modes*/
        typedef enum {
                MODE0 = SPI_MODE_0,
                MODE1 = SPI_MODE_1,
                MODE2 = SPI_MODE_2,
                MODE3 = SPI_MODE_3
        } Mode;
        struct Settings {
                const char* device; 
                unsigned long speed; 
                unsigned short delay; 
                unsigned char numBits; 
                unsigned int mode; 
        };

        Spi();
        ~Spi();
        int setup(const Settings& settings);
        int transfer(unsigned char *send, unsigned char *receive,
                 size_t numBytes);
        int setMode(unsigned char mode);
        int setNumBits(unsigned char numBits);
        int setSpeed(unsigned long speed);
        void cleanup();
private:
        const char* device;
        unsigned long speed;
        unsigned short delay;
        unsigned char numBits;
        unsigned char mode;
        int fd = -1;
        struct spi_ioc_transfer transaction;
        int openDevice(const char* device);
};