File Coverage

blib/lib/PINE64/MCP23008.pm

Criterion	Covered	Total	%
statement	12	53	22.6
branch	0	6	0.0
condition	0	6	0.0
subroutine	4	11	36.3
pod	7	7	100.0
total	23	83	27.7

#!/usr/bin/perl
use strict;
use Device::I2C;
use IO::Handle;
use Fcntl;

package PINE64::MCP23008;

our $VERSION = '0.901';

#global vars
my ($i2cbus, $addr, $gpext);
my $gpregval = 0; 	#init gpio register value to 0

my @pin_nums = (1,2,4,8,16,32,64,128);

sub new{
	my $class = shift;
	my $self = bless {}, $class;

	#first arg is device address
	$addr = $_[0];

	#second arg i2c bus; optional
	$i2cbus = $_[1];

	if($i2cbus eq ''){
		$i2cbus = '/dev/i2c-0';
	}#end if

	$gpext = Device::I2C->new($i2cbus, "r+");

	#init i2c device
	$gpext->checkDevice($addr);
	$gpext->selectDevice($addr);

	#init gp register val to all off
	$gpregval = 0;

	return $self;
}#end new

sub set_direction{
	#sets value of the IO direction register
	#ie 255 makes all input; 0 makes all output

	my $direction = $_[1];
	$gpext->writeByteData(0x00, $direction);
}#end set_direction

sub enable_pullup{
	#when a pin is configured as an input
	#you can enable internal 100K pull-up
	#resistors by writing to the GPPU register
	#0-255 are valid values: 0 - all disabled
	#255 - all enabled

	my $en_gppu = $_[1];
	$gpext->writeByteData(0x06, $en_gppu);
}#end enable_pullup

sub set_polarity{
	#sets the polarity of the gpio pins;
	#0 is normal polarity
	#255 is all pins reversed

	my $io_pol = $_[1];
	$gpext->writeByteData(0x01, $io_pol);
}#end set_polarity

sub write_pin{
	my $ind = $_[1];
	my $iox = $pin_nums[$ind];

	#1 or 0
	my $val = $_[2];

	#check 0x09 register to see if
	#pin already high; if so, do nothing
	my $regval = $gpext->readByteData(0x09);
	my $binout = sprintf("%08b", $regval);
	my @pinvals = split(//, $binout);
	@pinvals = reverse(@pinvals);
	my $already_high = $pinvals[$ind];

	if($val == 1 && $already_high == 0){
		$gpregval+=$iox;
	}#end if
	if($val == 0 && $already_high == 1){
		$gpregval-=$iox;
	}#end if

	$gpext->writeByteData(0x09, $gpregval);
}#end write_pin

sub read_pin{
	my $ind = $_[1];
	my $iox = $pin_nums[$ind];
	my $pinval = 0;

	#read GPIO register
	my $regval = $gpext->readByteData(0x09);

	#ensure 8 binary places are displayed
	my $binout = sprintf("%08b", $regval);

	#parse eight binary digits into an array
	my @pinvals = split(//, $binout);

	#reverse array to match pin #'s
	@pinvals = reverse(@pinvals);

	#value of pin is index of $pinvals
	$pinval = $pinvals[$ind];

	return $pinval;
}#end read_pin

sub read_gpio_register{
	#read GPIO register
	my $regval = $gpext->readByteData(0x09);

	return $regval;
}#end read_gpio_register

1;
__END__