SPI.h

/*
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <[email protected]>
 * Copyright (C) 2013-2017 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * Based on TMRh20 RF24 library, Copyright (c) 2015 Charles-Henri Hallard <[email protected]>
 */

#ifndef _SPI_H_
#define _SPI_H_

#include <stdio.h>
#include "bcm2835.h"
#include "RPi.h"

#define SPI_HAS_TRANSACTION

#define SPI_CLOCK_BASE 256000000

// SPI Clock divider
#define SPI_CLOCK_DIV1 BCM2835_SPI_CLOCK_DIVIDER_1
#define SPI_CLOCK_DIV2 BCM2835_SPI_CLOCK_DIVIDER_2
#define SPI_CLOCK_DIV4 BCM2835_SPI_CLOCK_DIVIDER_4
#define SPI_CLOCK_DIV8 BCM2835_SPI_CLOCK_DIVIDER_8
#define SPI_CLOCK_DIV16 BCM2835_SPI_CLOCK_DIVIDER_16
#define SPI_CLOCK_DIV32 BCM2835_SPI_CLOCK_DIVIDER_32
#define SPI_CLOCK_DIV64 BCM2835_SPI_CLOCK_DIVIDER_64
#define SPI_CLOCK_DIV128 BCM2835_SPI_CLOCK_DIVIDER_128
#define SPI_CLOCK_DIV256 BCM2835_SPI_CLOCK_DIVIDER_256
#define SPI_CLOCK_DIV512 BCM2835_SPI_CLOCK_DIVIDER_512
#define SPI_CLOCK_DIV1024 BCM2835_SPI_CLOCK_DIVIDER_1024
#define SPI_CLOCK_DIV2048 BCM2835_SPI_CLOCK_DIVIDER_2048
#define SPI_CLOCK_DIV4096 BCM2835_SPI_CLOCK_DIVIDER_4096
#define SPI_CLOCK_DIV8192 BCM2835_SPI_CLOCK_DIVIDER_8192
#define SPI_CLOCK_DIV16384 BCM2835_SPI_CLOCK_DIVIDER_16384
#define SPI_CLOCK_DIV32768 BCM2835_SPI_CLOCK_DIVIDER_32768
#define SPI_CLOCK_DIV65536 BCM2835_SPI_CLOCK_DIVIDER_65536

// SPI Data mode
#define SPI_MODE0 BCM2835_SPI_MODE0
#define SPI_MODE1 BCM2835_SPI_MODE1
#define SPI_MODE2 BCM2835_SPI_MODE2
#define SPI_MODE3 BCM2835_SPI_MODE3

#define LSBFIRST BCM2835_SPI_BIT_ORDER_LSBFIRST
#define MSBFIRST BCM2835_SPI_BIT_ORDER_MSBFIRST

const uint8_t SS   = 24;
const uint8_t MOSI = 19;
const uint8_t MISO = 21;
const uint8_t SCK  = 23;

class SPISettings
{

public:
    SPISettings()
    {
        init(SPI_CLOCK_DIV32, MSBFIRST, SPI_MODE0);
    }
    SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode)
    {
        uint16_t divider;

        if (clock >= SPI_CLOCK_BASE) {
            divider = SPI_CLOCK_DIV1;
        } else if (clock >= SPI_CLOCK_BASE / 2) {
            divider = SPI_CLOCK_DIV2;
        } else if (clock >= SPI_CLOCK_BASE / 4) {
            divider = SPI_CLOCK_DIV4;
        } else if (clock >= SPI_CLOCK_BASE / 8) {
            divider = SPI_CLOCK_DIV8;
        } else if (clock >= SPI_CLOCK_BASE / 16) {
            divider = SPI_CLOCK_DIV16;
        } else if (clock >= SPI_CLOCK_BASE / 32) {
            divider = SPI_CLOCK_DIV32;
        } else if (clock >= SPI_CLOCK_BASE / 64) {
            divider = SPI_CLOCK_DIV64;
        } else if (clock >= SPI_CLOCK_BASE / 128) {
            divider = SPI_CLOCK_DIV128;
        } else if (clock >= SPI_CLOCK_BASE / 256) {
            divider = SPI_CLOCK_DIV256;
        } else if (clock >= SPI_CLOCK_BASE / 512) {
            divider = SPI_CLOCK_DIV512;
        } else if (clock >= SPI_CLOCK_BASE / 1024) {
            divider = SPI_CLOCK_DIV1024;
        } else if (clock >= SPI_CLOCK_BASE / 2048) {
            divider = SPI_CLOCK_DIV2048;
        } else if (clock >= SPI_CLOCK_BASE / 4096) {
            divider = SPI_CLOCK_DIV4096;
        } else if (clock >= SPI_CLOCK_BASE / 8192) {
            divider = SPI_CLOCK_DIV8192;
        } else if (clock >= SPI_CLOCK_BASE / 16384) {
            divider = SPI_CLOCK_DIV16384;
        } else if (clock >= SPI_CLOCK_BASE / 32768) {
            divider = SPI_CLOCK_DIV32768;
        } else if (clock >= SPI_CLOCK_BASE / 65536) {
            divider = SPI_CLOCK_DIV65536;
        } else {
            // Default to 8Mhz
            divider = SPI_CLOCK_DIV32;
        }

        init(divider, bitOrder, dataMode);
    }

    uint16_t cdiv; 
    uint8_t border; 
    uint8_t dmode; 

private:
    void init(uint16_t divider, uint8_t bitOrder, uint8_t dataMode)
    {
        cdiv = divider;
        border = bitOrder;
        dmode = dataMode;
    }

    friend class SPIClass;
};

class SPIClass
{

public:
    inline static uint8_t transfer(uint8_t data);
    inline static void transfernb(char* tbuf, char* rbuf, uint32_t len);
    inline static void transfern(char* buf, uint32_t len);
    static void begin();
    static void end();
    static void setBitOrder(uint8_t bit_order);
    static void setDataMode(uint8_t data_mode);
    static void setClockDivider(uint16_t divider);
    static void chipSelect(int csn_pin);
    static void beginTransaction(SPISettings settings);
    static void endTransaction();
    static void usingInterrupt(uint8_t interruptNumber);
    static void notUsingInterrupt(uint8_t interruptNumber);

private:
    static uint8_t initialized; 
};

uint8_t SPIClass::transfer(uint8_t data)
{
    return bcm2835_spi_transfer(data);
}

void SPIClass::transfernb(char* tbuf, char* rbuf, uint32_t len)
{
    bcm2835_spi_transfernb( tbuf, rbuf, len);
}

void SPIClass::transfern(char* buf, uint32_t len)
{
    transfernb(buf, buf, len);
}

extern SPIClass SPI;

#endif