int config_i2c()

in shakti/bsp/drivers/i2c/i2c_driver.c [68:144]

• 58 lines of code
• 7 McCabe index (conditional complexity)

int config_i2c(i2c_struct * instance, unsigned char prescale_div, unsigned char scl_div)
{
	unsigned char temp = 0;
	log_debug("\tI2C: Initializing the Controller\n");

	if(prescale_div  != instance->prescale )
	{
		instance->prescale = prescale_div;
#ifdef DEBUG 
		temp = instance->prescale;

		if((temp | 0x00) != prescale_div)
		{
			log_error("\t Failed to write Prescale division Written Value: 0x%x; read Value: 0x%x\n", prescale_div, instance->prescale);
			return -ENXIO;
		}
		else
		{
			log_debug("\tPrescaler successfully initalized\n");
		}
#endif
	}

	if(scl_div != instance->scl )
	{
		instance->scl = scl_div;  //Setting the I2C clock value to be 1, which will set the clock for module and prescaler clock


#ifdef DEBUG 
		temp = instance->scl;

		/* Just reading the written value to see if all is well -- Compiler should not optimize this load!!! Compiler can just optimize the store to pointer address followed by load pointer to a register to just an immediate load to the register since clock register is not used anywhere -- but the purpose is lost. Don't give compiler optimizations */
		if((temp | 0x00) != scl_div)
		{
			log_error("\tClock initialization failed Write Value: 0x%x; read Value: 0x%x\n", scl_div, temp);
			return -ENXIO;
		}
		else
		{
			log_debug("\tClock successfully initalized\n");
		}
#endif
	}

	/* S1=0x80 S0 selected, serial interface off */
	log_debug("\tClearing the status register. \n");
	instance->control = I2C_PIN;

	// Reading set control Register Value to ensure sanctity
	log_debug("\tReading Status Register \n");
	temp = instance->control;

	//Check whether the status register is cleared or not.
	if((temp & 0x7f) != 0){
		log_error("\tDevice Not Recognized\n");
		return -ENXIO;
	}

	log_debug("\tWaiting for a specified time\n ");
	waitfor(900); //1 Second software wait -- Should be 900000 but setting to 900 now since simulation is already slow
	log_debug("\tDone Waiting \n ");
	log_info("\nControl: %x; Status: %x", instance->control, instance->status);
	/* Enable Serial Interface */
	instance->control = I2C_IDLE;
	waitfor(900); //1 Second software wait -- Should be 900000 but setting to 900 now since simulation is already slow

	temp = instance->status;

	/* Check to see if I2C is really in Idle and see if we can access the status register -- If not something wrong in initialization. This also verifies if Control is properly written since zero bit will be initialized to zero*/
	if(temp != (I2C_PIN | I2C_BB)){
		log_error("\n\tInitialization failed; Status Reg: %x\n", temp);
		return -ENXIO;
	}

	log_info("\tI2C Initialization success\n");
	return 0;
}