moxa da682c misc driver supported to access Programable LED, relay, DI/DO,
and on board uart interface on DA-682C series.

the driver is based on GPIO sysfs.

To use sysfs/gpio, you can write script to export/unexport

*** Manage GPIO from command line or script:

From the user level side this "operation" for reserve the GPIO is called "export" the GPIO. 
For make this export operation you simply need to echo the GPIO number you are interested to a special path as follow
(change XX with the GPIO number you need):

** Export Example:
#!/bin/sh
export_gpio() {
	local TARGET_GPIOCHIP=moxa-gpio
	local GPIOCHIP_NAME=gpiochip
	local GPIO_FS_PATH=/sys/class/gpio
	local GPIO_EXPORT="export"

	if [ x"$1" == x"unexport" ]; then
		GPIO_EXPORT="unexport"
	fi

	#
	# Export GPIOs
	#
	ls $GPIO_FS_PATH | grep $GPIOCHIP_NAME | while read -r chip ; do
		GPIO_LABEL=$(cat $GPIO_FS_PATH/$chip/label)
		if [[ "$GPIO_LABEL" != *"$TARGET_GPIOCHIP"* ]]; then
			continue
		fi

		pinstart=$(echo $chip | sed s/$GPIOCHIP_NAME/\\n/g)
		count=$(cat $GPIO_FS_PATH/$chip/ngpio)
		for (( i=0; i<${count}; i++ )); do
			echo $((${pinstart}+${i})) > $GPIO_FS_PATH/$GPIO_EXPORT 2>/dev/null
		done
	done
}

# export
export_gpio

# unexport
export_gpio unexport

** Set Example:
echo 1 > /sys/class/gpio/pled1/value
echo 0 > /sys/class/gpio/relay1/value

** Get Example:
cat /sys/class/gpio/pled1/value



*** Manage GPIO from application:
** Set Example:
sprintf(buf, "/sys/class/gpio/pled1/value", gpio);

fd = open(buf, O_WRONLY);

// Set GPIO high status
write(fd, "1", 1); 
// Set GPIO low status 
write(fd, "0", 1); 

close(fd);
