php-linux-gpio/lib/Gpio.php

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<?php
/*
* Copyright (C) 2014, NoccyLabs
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>
*/
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namespace NoccyLabs\Gpio;
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use NoccyLabs\Gpio\Exception\HardwareException;
class Gpio implements \ArrayAccess
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{
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// Direction
const DIR_IN = "in";
const DIR_OUT = "out";
// Values
const VAL_HIGH = 1;
const VAL_LOW = 0;
// Edges
const EDGE_NONE = "none";
const EDGE_RISING = "rising";
const EDGE_FALLING = "faling";
const EDGE_BOTH = "both";
protected $gpio = array();
/** @var NoccyLabs\Gpio\GpioMapperInterface */
protected $mapper;
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protected $dummy;
public function __construct($dummy=false)
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{
if (!$dummy) {
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if (!file_exists("/sys/class/gpio")) {
throw new HardwareException("gpio sysfs is not available");
}
if (!is_writable("/sys/class/gpio/export")) {
throw new HardwareException("gpio sysfs is not writable");
}
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}
$this->dummy = $dummy;
}
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public function setMapper(GpioMapperInterface $mapper=null)
{
$this->mapper = $mapper;
return $this;
}
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/**
* Get a pin, optionally via previously specified mapper.
*
* @interface ArrayAccess
* @param int
*/
public function offsetGet($index)
{
if ($this->mapper) {
$index = $this->mapper->mapLogicalToGpioPin($index);
}
if (empty($this->gpio[$index])) {
if ($this->dummy) {
$gpio = new DummyGpioPin($index, $this);
} else {
$gpio = new GpioPin($index, $this);
}
$this->gpio[$index] = $gpio;
}
return $this->gpio[$index];
}
/**
* Check if a GPIO is exported
*
* @interface ArrayAccess
* @param int
*/
public function offsetExists($index)
{
return array_key_exists($index, $this->gpio);
}
/**
* Not callable, get the requested pin via offsetGet() instead.
*
* @interface ArrayAccess
* @throws Exception
* @param int
* @param mixed
*/
public function offsetSet($index,$value)
{ throw new \Exception(); }
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/**
* Unlink and unexport an exported GPIO
*
* @interface ArrayAccess
* @param int
*/
public function offsetUnset($index)
{
$this->gpio[$index]->unexport();
unset($this->gpio[$index]);
}
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}