Add Pi LCD node for simple LCD modules

hardware/PiLcd/pilcd.js

@@ -0,0 +1,103 @@
+/**
+ * Copyright 2015 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+module.exports = function(RED) {
+    "use strict";
+    var util = require("util");
+    var spawn = require('child_process').spawn;
+    var fs = require('fs');
+
+    var gpioCommand = __dirname + '/nrlcd';
+
+    if (!fs.existsSync("/dev/ttyAMA0")) { // unlikely if not on a Pi
+        //util.log("Info : Ignoring Raspberry Pi specific node.");
+        throw "Info : Ignoring Raspberry Pi specific node.";
+    }
+
+    if (!fs.existsSync("/usr/share/doc/python-rpi.gpio")) {
+        util.log("[rpi-lcd] Info : Can't find Pi RPi.GPIO python library.");
+        throw "Warning : Can't find Pi RPi.GPIO python library.";
+    }
+
+    if (!(1 & parseInt ((fs.statSync(gpioCommand).mode & parseInt ("777", 8)).toString (8)[0]))) {
+        util.log("[rpi-lcd] Error : " + gpioCommand + " needs to be executable.");
+        throw "Error : " + gpioCommand + " must to be executable.";
+    }
+
+    function PiLcdNode(n) {
+        RED.nodes.createNode(this, n);
+        this.pins = n.pins;
+        var node = this;
+
+        function inputlistener(msg) {
+            var out = msg.payload.toString();
+            if (RED.settings.verbose) { node.log("inp: " + msg.payload); }
+            if (node.child !== null) { node.child.stdin.write(msg.payload + "\n"); }
+            else { node.warn("Command not running"); }
+        }
+
+        if (node.pins !== undefined) {
+            node.child = spawn(gpioCommand, [node.pins]);
+            node.running = true;
+            if (RED.settings.verbose) { node.log("pin: " + node.pins + " :"); }
+            node.on("input", inputlistener);
+
+            node.child.stdout.on('data', function(data) {
+                if (RED.settings.verbose) { node.log("out: " + data + " :"); }
+            });
+
+            node.child.stderr.on('data', function(data) {
+                if (RED.settings.verbose) { node.log("err: " + data + " :"); }
+            });
+
+            node.child.on('close', function(code) {
+                if (RED.settings.verbose) { node.log("ret: " + code + " :"); }
+                node.child = null;
+                node.running = false;
+            });
+
+            node.child.on('error', function(err) {
+                if (err.errno === "ENOENT") { node.warn('Command not found'); }
+                else if (err.errno === "EACCES") { node.warn('Command not executable'); }
+                else { node.log('error: ' + err); }
+            });
+
+        }
+        else {
+            node.error("Invalid GPIO pins: " + node.pin);
+        }
+
+        var wfi = function(done) {
+            if (!node.running) {
+                if (RED.settings.verbose) { node.log("end"); }
+                done();
+                return;
+            }
+            setTimeout(function() { wfi(done); }, 333);
+        }
+
+        node.on("close", function(done) {
+            delete pinsInUse[node.pin];
+            if (node.child != null) {
+                node.child.stdin.write("c:lose" + node.pin);
+                node.child.kill('SIGKILL');
+            }
+            wfi(done);
+        });
+
+    }
+    RED.nodes.registerType("rpi-lcd", PiLcdNode);
+}