openwrt/package/base-files/files/etc/init.d/gpio_switch

#!/bin/sh /etc/rc.common
# Copyright (C) 2015 OpenWrt.org

START=94
STOP=10
USE_PROCD=1


load_gpio_switch()
{
	local name
	local gpio_pin
	local value

	config_get gpio_pin "$1" gpio_pin
	config_get name "$1" name
	config_get value "$1" value 0

	[ -z "$gpio_pin" ] && {
		echo >&2 "Skipping gpio_switch '$name' due to missing gpio_pin"
		return 1
	}

	local gpio_path
	if [ -n "$(echo "$gpio_pin" | grep -E "^[0-9]+$")" ]; then
		gpio_path="/sys/class/gpio/gpio${gpio_pin}"

		# export GPIO pin for access
		[ -d "$gpio_path" ] || {
			echo "$gpio_pin" >/sys/class/gpio/export
			# we need to wait a bit until the GPIO appears
			[ -d "$gpio_path" ] || sleep 1
		}

		# direction attribute only exists if the kernel supports changing the
		# direction of a GPIO
		if [ -e "${gpio_path}/direction" ]; then
			# set the pin to output with high or low pin value
			{ [ "$value" = "0" ] && echo "low" || echo "high"; } \
				>"$gpio_path/direction"
		else
			{ [ "$value" = "0" ] && echo "0" || echo "1"; } \
				>"$gpio_path/value"
		fi
	else
		gpio_path="/sys/class/gpio/${gpio_pin}"

		[ -d "$gpio_path" ] && {
			{ [ "$value" = "0" ] && echo "0" || echo "1"; } \
				>"$gpio_path/value"
		}
	fi
}

service_triggers()
{
	procd_add_reload_trigger "system"
}

start_service()
{
	[ -e /sys/class/gpio/ ] && {
		config_load system
		config_foreach load_gpio_switch gpio_switch
	}
}