#include "project.h"


#define I2C I2C1

#define SCL 	GPIO6
#define SDA	GPIO7

void
i2c_clear_start (uint32_t i2c)
{
  I2C_CR1 (i2c) &= ~(uint32_t) I2C_CR1_START;
}

#if 0
static void
i2cp_ds (void)
{
  uint32_t i2c = I2C;
  printf ("CR1=%08x CR2=%08x\r\n", (unsigned) I2C_CR1 (i2c),
          (unsigned) I2C_CR2 (i2c));
  printf ("SR1=%08x SR2=%08x\r\n", (unsigned) I2C_SR1 (i2c),
          (unsigned) I2C_SR2 (i2c));


  usart1_drain ();
}
#endif



void
i2cp_start (void)
{
  i2c_send_start (I2C);
  while (!((I2C_SR1 (I2C) & I2C_SR1_SB)
           & (I2C_SR2 (I2C) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
}

void
i2cp_abort_start (void)
{
  i2c_clear_start (I2C);
  delay_us (10);
}

void
i2cp_stop (void)
{
  i2c_send_stop (I2C);
}


void
i2cp_abort_stop (void)
{
  i2c_clear_stop (I2C);
  delay_us (10);
}

int
i2cp_send_data (uint8_t v)
{
  uint32_t reg;

  i2c_send_data (I2C, v);

  while (!
         ((reg =
           I2C_SR1 (I2C)) & (I2C_SR1_BTF | I2C_SR1_BERR | I2C_SR1_ARLO |
                             I2C_SR1_AF | I2C_SR1_PECERR | I2C_SR1_TIMEOUT |
                             I2C_SR1_SMBALERT)));
  I2C_SR1 (I2C) =
    reg & ~(I2C_SR1_BERR | I2C_SR1_ARLO | I2C_SR1_AF | I2C_SR1_PECERR |
            I2C_SR1_TIMEOUT | I2C_SR1_SMBALERT);


  return (reg & I2C_SR1_BTF) ? 0 : -1;
}

/*0 on success 1 on failure*/
int
i2cp_start_transaction (uint8_t a, int wnr)
{
  uint32_t reg;
  uint32_t __attribute__ ((unused)) dummy;

  i2c_send_start (I2C);
  while (!((I2C_SR1 (I2C) & I2C_SR1_SB)
           & (I2C_SR2 (I2C) & (I2C_SR2_MSL | I2C_SR2_BUSY))));

  i2c_send_7bit_address (I2C, a, wnr);

  while (!
         ((reg =
           I2C_SR1 (I2C)) & (I2C_SR1_ADDR | I2C_SR1_BERR | I2C_SR1_ARLO |
                             I2C_SR1_AF | I2C_SR1_PECERR | I2C_SR1_TIMEOUT |
                             I2C_SR1_SMBALERT)));
  dummy = I2C_SR2 (I2C);

  I2C_SR1 (I2C) =
    reg & ~(I2C_SR1_BERR | I2C_SR1_ARLO | I2C_SR1_AF | I2C_SR1_PECERR |
            I2C_SR1_TIMEOUT | I2C_SR1_SMBALERT);


  return (reg == 0x82) ? 0 : -1;
}


static int mutex = 0;

int
i2cp_lock (void)
{
  if (__sync_add_and_fetch (&mutex, 1) != 1)
    {
      __sync_sub_and_fetch (&mutex, 1);
      return -1;
    }

  return 0;
}


void
i2cp_unlock (void)
{
  __sync_sub_and_fetch (&mutex, 1);
}

 /*This is stupid, it bit bangs a dummy transaction to get the host i2c controller back in the game */
static void
i2cp_reset_sm (void)
{
  int i;

  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_50_MHZ,
                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO_I2C1_SCL | GPIO_I2C1_SDA);

  gpio_set (GPIOB, GPIO_I2C1_SDA);
  gpio_set (GPIOB, GPIO_I2C1_SCL);
  delay_us (10);
  gpio_clear (GPIOB, GPIO_I2C1_SDA);
  delay_us (10);
  gpio_clear (GPIOB, GPIO_I2C1_SCL);

  for (i = 0; i < 9; ++i)
    {
      delay_us (10);
      gpio_set (GPIOB, GPIO_I2C1_SCL);
      delay_us (10);
      gpio_clear (GPIOB, GPIO_I2C1_SCL);
      delay_us (10);
    }
  gpio_set (GPIOB, GPIO_I2C1_SCL);
  delay_us (10);
  gpio_set (GPIOB, GPIO_I2C1_SDA);
  delay_us (10);

}

void
i2cp_start_dma (uint8_t * buf, int len)
{
  dma_channel_reset (DMA1, DMA_CHANNEL6);
  dma_set_peripheral_address (DMA1, DMA_CHANNEL6, (uint32_t) & I2C1_DR);
  dma_set_memory_address (DMA1, DMA_CHANNEL6, (uint32_t) buf);
  dma_set_number_of_data (DMA1, DMA_CHANNEL6, len);
  dma_set_read_from_memory (DMA1, DMA_CHANNEL6);
  dma_enable_memory_increment_mode (DMA1, DMA_CHANNEL6);
  dma_set_peripheral_size (DMA1, DMA_CHANNEL6, DMA_CCR_PSIZE_8BIT);
  dma_set_memory_size (DMA1, DMA_CHANNEL6, DMA_CCR_MSIZE_8BIT);
  dma_set_priority (DMA1, DMA_CHANNEL6, DMA_CCR_PL_MEDIUM);
  dma_enable_transfer_complete_interrupt (DMA1, DMA_CHANNEL6);
  dma_enable_transfer_error_interrupt (DMA1, DMA_CHANNEL6);
  dma_enable_channel (DMA1, DMA_CHANNEL6);

  i2c_enable_dma (I2C1);

}

int
i2cp_dma_in_progress (void)
{
  return !(DMA1_ISR & (DMA_ISR_TCIF6 | DMA_ISR_TEIF6));
}

void
i2cp_stop_dma (void)
{
  DMA1_IFCR |= DMA_IFCR_CTCIF7 | DMA_IFCR_CTEIF6 | DMA_IFCR_CGIF6;

  dma_disable_transfer_complete_interrupt (DMA1, DMA_CHANNEL6);
  dma_disable_transfer_error_interrupt (DMA1, DMA_CHANNEL6);

  i2c_disable_dma (I2C1);
  dma_disable_channel (DMA1, DMA_CHANNEL7);
}

void
i2cp_reset (void)
{
  while (i2cp_lock ());
  i2cp_start ();
  i2cp_abort_start ();
  i2cp_stop ();
  i2cp_abort_stop ();

  i2cp_start ();
  i2cp_abort_start ();
  i2cp_stop ();
  i2cp_abort_stop ();
  i2cp_unlock ();
}



void
i2cp_scan (void)
{
  int i, r;

  return;
  i2cp_reset ();

  printf ("Probing bus\r\n");
  for (i = 0; i < 128; ++i)
    {
      while (i2cp_lock ());
      i2cp_start ();
      i2cp_abort_start ();
      i2cp_stop ();
      i2cp_abort_stop ();
      r = i2cp_start_transaction (i, I2C_WRITE);
      i2cp_stop ();
      i2cp_unlock ();
      if (!r)
        printf ("Found device at address 0x%x\r\n", i);
      usart1_drain ();
    }
  printf ("Done\r\n");
  i2cp_reset ();

}

void
i2cp_init (void)
{
  rcc_periph_clock_enable (RCC_I2C1);
  rcc_periph_clock_enable (RCC_DMA1);

  while (i2cp_lock ());


  i2c_peripheral_enable (I2C);
  i2c_clear_start (I2C);
  i2c_clear_stop (I2C);
  i2c_reset (I2C);
  i2c_peripheral_enable (I2C);

  I2C_CR1 (I2C) |= I2C_CR1_SWRST;
  delay_us (1000);
  I2C_CR1 (I2C) &= ~I2C_CR1_SWRST;


  i2cp_reset_sm ();

  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_50_MHZ,
                 GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN,
                 GPIO_I2C1_SCL | GPIO_I2C1_SDA);

  i2c_set_clock_frequency (I2C, I2C_CR2_FREQ_36MHZ);
  i2c_set_standard_mode (I2C);
  i2c_set_ccr (I2C, 0x200);     /* t_high=t_high=CCR * Tpclk1 */
  i2c_set_trise (I2C, 0x0b);

  i2c_set_own_7bit_slave_address (I2C, 0x00);

  i2c_peripheral_enable (I2C);
  i2cp_unlock ();
}