#include "i2c.h"
#include "stm32f10x_i2c.h"
#include "stm32f10x_gpio.h"
#include "porting.h"

void i2cInit(I2C_TypeDef* I2Cx)
{
	if (I2Cx == I2C1) {
		i2c1Init();
	}
	else {
		THROW_ERROR(E_I2C_NON_EXISTANT);
	}
}

void i2c1Init(void)
{
	// Initialization structs
	GPIO_InitTypeDef i2c_gpio;
	I2C_InitTypeDef i2c;
	// Turn on clocks
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    //Configure I2C module
    i2c.I2C_ClockSpeed = 100000;
    i2c.I2C_Mode = I2C_Mode_I2C;
    i2c.I2C_DutyCycle = I2C_DutyCycle_2;
    i2c.I2C_OwnAddress1 = 0x15;
    i2c.I2C_Ack = I2C_Ack_Enable;
    i2c.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_Init(I2C1, &i2c);
    //Additionally we need to initialize corresponding GPIOs
    i2c_gpio.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    i2c_gpio.GPIO_Mode = GPIO_Mode_AF_OD; // Open drain only if you have pull-up resistors
    i2c_gpio.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &i2c_gpio);
    // Enable I2C 1
    I2C_Cmd(I2C1, ENABLE);
    DEBUG_MSG("I2C1 initialized.");
}

uint8_t i2cPing(I2C_TypeDef* I2Cx, uint8_t slave_addr)
{
	DEBUG_MSG("Searching for: %d\n", slave_addr);
	// Wait until I2Cx is not busy anymore
	while (I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));
	// Generate start condition
	I2C_GenerateSTART(I2Cx, ENABLE);
	while (!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
	// Send slave address
	I2C_Send7bitAddress(I2Cx, slave_addr<<1, I2C_Direction_Transmitter);
	// Wait for I2C EV5.
	volatile uint32_t timeout = 0xFFFF;
	while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)) {
		if (timeout == 0) {
			break;
		} else {
			timeout--;
		}
	}
	I2C_GenerateSTOP(I2Cx, ENABLE);
	if (timeout > 0) {
		DEBUG_MSG("Slave found\n\r");
		return 1;
	} else {
		DEBUG_MSG("Slave not found\n\r");
	}
	return 0;
}

void i2cStartTransmission(I2C_TypeDef* I2Cx, uint8_t dir,  uint8_t slave_addr)
{
    // Wait for I2C module to become ready
    while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));
    // Generate I2C start condition
    I2C_GenerateSTART(I2Cx, ENABLE);
    // Waiting for EV5
    while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT));
    // The 7 bit address needs to be shifted by 1
    I2C_Send7bitAddress(I2Cx, slave_addr<<1, dir);
    // Depending on whether the master is reading or writing another event is triggered
    if(dir== I2C_Direction_Transmitter)
    {
    	while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    }
    if(dir== I2C_Direction_Receiver)
    {
    	while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));
    }
}

void i2cWrite(I2C_TypeDef* I2Cx, uint8_t* data, uint16_t len, uint32_t timeout)
{
  	if(len-- >= 1) {
    	I2C_SendData(I2Cx, *data++);
    }
    while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_TRANSMITTED) && timeout) {
    	timeout--;
    }
}

void i2cAckOn(I2C_TypeDef* I2Cx)
{
	I2C_AcknowledgeConfig(I2Cx, ENABLE);
}

void i2cAckOff(I2C_TypeDef* I2Cx)
{
	I2C_AcknowledgeConfig(I2Cx, DISABLE);
}

uint8_t i2cRead(I2C_TypeDef* I2Cx)
{
    while(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED));
    uint8_t data = I2C_ReceiveData(I2Cx);
    return data;
}

void i2cEndTransmission(I2C_TypeDef* I2Cx)
{
    I2C_GenerateSTOP(I2Cx, ENABLE);
    while(I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF));
}