Driver for hardware IO port

opto_ac5.0.digital-read - Add this to a thread to read all the input points.
opto_ac5.0.digital-write - Add this to a thread to write all the output points and LEDs.

// These methods are exported to the HAL.
static void Device_DigitalInRead(void *this, long period);
static void Device_DigitalOutWrite(void *this, long period);

// here we read inputs from board
// we read the current data (variable 'pins') of the first port. Then for each of the 24 points
// we compare to the mask of the first port to see which of the 24 io points are inputs (the bits that are false)
// if it is an input then check 'pins' against the mask to see if input bit is true
// update the HAL pin and not-pin accoringly. shift the mask then do the next point (of 24 io points)
// after all pins done-increase 'portnum' to 1 set offset to the offset for port1
// then do it all again on the second port

static void
Device_DigitalInRead(void *arg, long period)
{
    board_data_t			*pboard = (board_data_t *)arg;
    DigitalPinsParams			*pDigital;
    int					i, portnum=0;
    unsigned long			pins, offset=DATA_READ_OFFSET_0, mask;

    // For each port.
	while (portnum<2)
		{
			mask=1;
			pDigital = &pboard->port[portnum].io[0];

			// Read digital I/O register.
			pins=	readl (pboard->base + (offset));
   			for(i = 0; i < 24; i++,pDigital++)
			{
				if ((pboard->port[portnum].mask & mask) ==0) // is it an input bit ?
				{
				    if ((pins & mask) !=0){	*(pDigital->pValue) =0;
					}else{	*(pDigital->pValue) = 1;	}
					// Update not pin.
				    *(pDigital->pValueNot) = !*(pDigital->pValue);
				}
	  		 	 mask <<=1;// shift mask
			}
			portnum++;
			offset=DATA_READ_OFFSET_1;// change to offset for port1
 		}
}

// we check each ports mask (port[portnum].mask) against a mask bit to see which of the 24 points of i/o are inputs (a false bit is an input)
// then export HAL pins mapped to the proper io structure
// HAL pin numbers represent position in an opto22 relay rack (eg. pin 00 is position 0)
// this way you can configure the i/o in any way for all the 24 points of each port

static int Device_ExportDigitalInPinsParametersFunctions(board_data_t *this, int comp_id, int boardId)
{
    int					halError=0, channel,mask,portnum=0;
    char				name[HAL_NAME_LEN + 1];

    // Export pins and parameters.
	while (portnum<2)
		{
		mask=1;
   		 for(channel = 0; channel < 24; channel++)
		   {
			if ((this->port[portnum].mask & mask)==0)//physical input?
			{
			// Pins.
			if((halError = hal_pin_bit_newf(HAL_OUT, &(this->port[portnum].io[channel].pValue),
			  comp_id, "opto-ac5.%d.port%d.in-%02d", boardId, portnum, channel)) != 0)
			    break;

			if((halError = hal_pin_bit_newf(HAL_OUT, &(this->port[portnum].io[channel].pValueNot),
			  comp_id, "opto-ac5.%d.port%d.in-%02d-not", boardId, portnum, channel)) != 0)
			    break;

			// Init pin.
			*(this->port[portnum].io[channel].pValue) = 0;
			*(this->port[portnum].io[channel].pValueNot) = 1;
			}
			mask <<=1;
		   }

		   portnum ++;	
	 	}

    // Export functions.
    if(!halError){
	rtapi_snprintf(name, sizeof(name), "opto-ac5.%d.digital-read", boardId);
	halError = hal_export_funct(name, Device_DigitalInRead, this, 0, 0, comp_id);
    }

    if(halError){
	rtapi_print_msg(RTAPI_MSG_ERR, "ERROR OPTO22_AC5---exporting digital inputs to HAL failed\n");
	return(-1);
    }

    return(0);
}

// Export functions.
    if(!halError){
	rtapi_snprintf(name, sizeof(name), "opto-ac5.%d.digital-read", boardId);
	halError = hal_export_funct(name, Device_DigitalInRead, this, 0, 0, comp_id);
    }