/*
 * Copyright (c) 2016, Alex Taradov <alex@taradov.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*- Includes ----------------------------------------------------------------*/
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include "samd21.h"
#include "hal_gpio.h"
#include "spi_master.h"
#include "arduino_platform.h"
#include "ost_hal.h"

/*
 +------------+------------------+--------+-----------------+--------+-----------------------+---------+---------+--------+--------+----------+----------+
 | Pin number |  MKR  Board pin  |  PIN   | Notes           | Peri.A |     Peripheral B      | Perip.C | Perip.D | Peri.E | Peri.F | Periph.G | Periph.H |
 |            |                  |        |                 |   EIC  | ADC |  AC | PTC | DAC | SERCOMx | SERCOMx |  TCCx  |  TCCx  |    COM   | AC/GLCK  |
 |            |                  |        |                 |(EXTINT)|(AIN)|(AIN)|     |     | (x/PAD) | (x/PAD) | (x/WO) | (x/WO) |          |          |
 +------------+------------------+--------+-----------------+--------+-----+-----+-----+-----+---------+---------+--------+--------+----------+----------+
 |            |       SPI        |        |                 |        |     |     |     |     |         |         |        |        |          |          |
 | 08         | MOSI             |  PA16  |                 |  *00   |     |     | X04 |     |  *1/00  |   3/00  |*TCC2/0 | TCC0/6 |          | GCLK_IO2 |
 | 09         | SCK              |  PA17  |                 |  *01   |     |     | X05 |     |  *1/01  |   3/01  | TCC2/1 | TCC0/7 |          | GCLK_IO3 |
 | 10         | MISO             |  PA19  |                 |   03   |     |     | X07 |     |  *1/03  |   3/03  |* TC3/1 | TCC0/3 | I2S/SD0  | AC/CMP1  |
 
 | 00         | D0               |  PA22  |                 |  *06   |     |     | X10 |     |   3/00  |   5/00  |* TC4/0 | TCC0/4 |          | GCLK_IO6 |
 | 01         | D1               |  PA23  |                 |  *07   |     |     | X11 |     |   3/01  |   5/01  |* TC4/1 | TCC0/5 | USB/SOF  | GCLK_IO7 |
 +------------+------------------+--------+-----------------+--------------------+-----+-----+---------+---------+--------+--------+----------+----------+
*/

// DO ---> DC
// D1 ---> SS

HAL_GPIO_PIN(MOSI,            A, 16);
HAL_GPIO_PIN(MISO,            A, 19);
HAL_GPIO_PIN(SCLK,            A, 17);
HAL_GPIO_PIN(SS,              A, 23);
HAL_GPIO_PIN(DC,              A, 22);
#define SPI_SERCOM              SERCOM3
#define SERCOMx_GCLK_ID_CORE    GCM_SERCOM3_CORE

#define PAD_SPI_TX   SPI_PAD_0_SCK_1
#define PAD_SPI_RX   SERCOM_RX_PAD_3

//-----------------------------------------------------------------------------
void spi_display_init(int freq, int mode)
{
  int baud = F_CPU / (2 * freq) - 1;

  if (baud < 0)
    baud = 0;

  if (baud > 255)
    baud = 255;

  freq = F_CPU / (2 * (baud + 1));

  HAL_GPIO_MISO_in();
  HAL_GPIO_MISO_pmuxen(PIO_SERCOM_ALT);

  HAL_GPIO_MOSI_out();
  HAL_GPIO_MOSI_pmuxen(PIO_SERCOM_ALT);

  HAL_GPIO_SCLK_out();
  HAL_GPIO_SCLK_pmuxen(PIO_SERCOM_ALT);

  HAL_GPIO_SS_out();
  HAL_GPIO_SS_set();

  HAL_GPIO_DC_out();
  HAL_GPIO_DC_set();

  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(SERCOMx_GCLK_ID_CORE) | GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0;
  while(GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY);

  SPI_SERCOM->SPI.CTRLA.reg = SERCOM_SPI_CTRLA_SWRST;
  while (SPI_SERCOM->SPI.CTRLA.reg & SERCOM_SPI_CTRLA_SWRST);

  SPI_SERCOM->SPI.CTRLB.reg = SERCOM_SPI_CTRLB_RXEN;

  SPI_SERCOM->SPI.BAUD.reg = baud;

  SPI_SERCOM->SPI.CTRLA.reg = SERCOM_SPI_CTRLA_ENABLE |
      SERCOM_SPI_CTRLA_DIPO(PAD_SPI_RX) | SERCOM_SPI_CTRLA_DOPO(PAD_SPI_TX) |
      ((mode & 1) ? SERCOM_SPI_CTRLA_CPHA : 0) |
      ((mode & 2) ? SERCOM_SPI_CTRLA_CPOL : 0) |
      SERCOM_SPI_CTRLA_MODE_SPI_MASTER;
}


//-----------------------------------------------------------------------------
void spi_display_ss(int state)
{
  HAL_GPIO_SS_write(state);
}

//-----------------------------------------------------------------------------
void spi_display_dc(int state)
{
  HAL_GPIO_DC_write(state);
}

//-----------------------------------------------------------------------------
uint8_t spi_display_transfer(uint8_t byte)
{
//  while (!SPI_SERCOM->SPI.INTFLAG.bit.DRE);
  SPI_SERCOM->SPI.DATA.bit.DATA = byte;
  while (!SPI_SERCOM->SPI.INTFLAG.bit.RXC);
  return SPI_SERCOM->SPI.DATA.bit.DATA;  // Reading data
}

void spi_display_reset()
{
    //Setting the Software Reset bit to 1
    //Setting the Software Reset bit to 1
  SPI_SERCOM->SPI.CTRLA.bit.SWRST = 1;

  //Wait both bits Software Reset from CTRLA and SYNCBUSY are equal to 0
  while(SPI_SERCOM->SPI.CTRLA.bit.SWRST || SPI_SERCOM->SPI.SYNCBUSY.bit.SWRST);
}

void spi_display_enable()
{
  //Setting the enable bit to 1
  SPI_SERCOM->SPI.CTRLA.bit.ENABLE = 1;

  while(SPI_SERCOM->SPI.SYNCBUSY.bit.ENABLE)
  {
    //Waiting then enable bit from SYNCBUSY is equal to 0;
  }
}