#include "i2c.h"

#include "stm32.h"

void I2C::enable() {
	RCC.enable(RCC.I2C2);
	asm volatile("nop");
	
	I2C2.CR1 = 0x8000;
	I2C2.CR1 = 0;
	
	I2C2.CR2 = 36;
	I2C2.TRISE = 37;
	I2C2.CCR = 180;
	I2C2.CR1 = 1;
}

void I2C::write_reg(uint8_t addr, uint8_t reg, uint8_t data) {
	I2C2.CR1 |= 0x100;
	while(!(I2C2.SR1 & 0x01));
	
	I2C2.DR = (addr << 1) | 0;
	while (!(I2C2.SR1 & 0x02));
	I2C2.SR2;
	
	I2C2.DR = reg;
	while (!(I2C2.SR1 & 0x80));
	
	I2C2.DR = data;
	while (!(I2C2.SR1 & 0x04));
	
	I2C2.CR1 |= 0x200;
}

void I2C::read_reg(uint8_t addr, uint8_t reg, uint8_t len, uint8_t* buf) {
	I2C2.CR1 |= 0x100;
	while(!(I2C2.SR1 & 0x01));
	
	I2C2.DR = (addr << 1) | 0;
	while (!(I2C2.SR1 & 0x02));
	I2C2.SR2;
	
	I2C2.DR = reg;
	while (!(I2C2.SR1 & 0x80));
	
	I2C2.CR1 |= 0x100;
	while(!(I2C2.SR1 & 0x01));
	
	I2C2.DR = (addr << 1) | 1;
	while (!(I2C2.SR1 & 0x02));
	I2C2.SR2;
	
	I2C2.CR1 |= 0x400; // Set ACK.
	
	while(len) {
		if(len == 3) {
			while (!(I2C2.SR1 & 0x04)); // Wait for BTF
			
			I2C2.CR1 &= ~0x400; // Clear ACK.
			*buf++ = I2C2.DR;
			len--;
			
			I2C2.CR1 |= 0x200; // Set STOP.
			*buf++ = I2C2.DR;
			len--;
			
		} else {
			while (!(I2C2.SR1 & 0x40)); // Wait for RXNE
			
			*buf++ = I2C2.DR;
			len--;
		}
	}
}