Linux: Add support for SPIDEV (#734)

RPi and Linux refactor.

Add GPIO Sysfs for GPIO operations.

Update configure script.

Fix some cppcheck warnings.

Add serial emulation that prints to stdout.

Fix some file headers.

drivers/Linux/GPIO.cpp

@@ -0,0 +1,211 @@
+/*
+ * The MySensors Arduino library handles the wireless radio link and protocol
+ * between your home built sensors/actuators and HA controller of choice.
+ * The sensors forms a self healing radio network with optional repeaters. Each
+ * repeater and gateway builds a routing tables in EEPROM which keeps track of the
+ * network topology allowing messages to be routed to nodes.
+ *
+ * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
+ * Copyright (C) 2013-2017 Sensnology AB
+ * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
+ *
+ * Documentation: http://www.mysensors.org
+ * Support Forum: http://forum.mysensors.org
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+#include "GPIO.h"
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "log.h"
+
+// Declare a single default instance
+GPIO gpio = GPIO();
+
+GPIO::GPIO()
+{
+	FILE *f;
+	DIR* dp;
+	char file[64];
+
+	dp = opendir("/sys/class/gpio");
+	if (dp == NULL) {
+		logError("Could not open /sys/class/gpio directory");
+		exit(1);
+	}
+
+	lastPinNum = 0;
+
+	while (true) {
+		dirent *de = readdir(dp);
+		if (de == NULL) {
+			break;
+		}
+
+		if (strncmp("gpiochip", de->d_name, 8) == 0) {
+			sprintf(file, "/sys/class/gpio/%s/base", de->d_name);
+			f = fopen(file, "r");
+			int base;
+			if (fscanf(f, "%d", &base) == EOF) {
+				logError("Failed to open %s\n", file);
+				base = 0;
+			}
+			fclose(f);
+
+			sprintf(file, "/sys/class/gpio/%s/ngpio", de->d_name);
+			f = fopen(file, "r");
+			int ngpio;
+			if (fscanf(f, "%d", &ngpio) == EOF) {
+				logError("Failed to open %s\n", file);
+				ngpio = 0;
+			}
+			fclose(f);
+
+			int max = ngpio + base - 1;
+			if (lastPinNum < max) {
+				lastPinNum = max;
+			}
+		}
+	}
+	closedir(dp);
+
+	exportedPins = new uint8_t[lastPinNum + 1];
+
+	for (int i = 0; i < lastPinNum + 1; ++i) {
+		exportedPins[i] = 0;
+	}
+}
+
+GPIO::GPIO(const GPIO& other)
+{
+	lastPinNum = other.lastPinNum;
+
+	exportedPins = new uint8_t[lastPinNum + 1];
+	for (int i = 0; i < lastPinNum + 1; ++i) {
+		exportedPins[i] = other.exportedPins[i];
+	}
+}
+
+GPIO::~GPIO()
+{
+	FILE *f;
+
+	for (int i = 0; i < lastPinNum + 1; ++i) {
+		if (exportedPins[i]) {
+			f = fopen("/sys/class/gpio/unexport", "w");
+			fprintf(f, "%d\n", i);
+			fclose(f);
+		}
+	}
+
+	delete [] exportedPins;
+}
+
+void GPIO::pinMode(uint8_t pin, uint8_t mode)
+{
+	FILE *f;
+
+	if (pin > lastPinNum) {
+		return;
+	}
+
+	f = fopen("/sys/class/gpio/export", "w");
+	fprintf(f, "%d\n", pin);
+	fclose(f);
+
+	int counter = 0;
+	char file[128];
+	sprintf(file, "/sys/class/gpio/gpio%d/direction", pin);
+
+	while ((f = fopen(file,"w")) == NULL) {
+		// Wait 10 seconds for the file to be accessible if not open on first attempt
+		sleep(1);
+		counter++;
+		if (counter > 10) {
+			logError("Could not open /sys/class/gpio/gpio%u/direction", pin);
+			exit(1);
+		}
+	}
+	if (mode == INPUT) {
+		fprintf(f, "in\n");
+	} else {
+		fprintf(f, "out\n");
+	}
+
+	exportedPins[pin] = 1;
+
+	fclose(f);
+}
+
+void GPIO::digitalWrite(uint8_t pin, uint8_t value)
+{
+	FILE *f;
+	char file[128];
+
+	if (pin > lastPinNum) {
+		return;
+	}
+	if (0 == exportedPins[pin]) {
+		pinMode(pin, OUTPUT);
+	}
+
+	sprintf(file, "/sys/class/gpio/gpio%d/value", pin);
+	f = fopen(file, "w");
+
+	if (value == 0)	{
+		fprintf(f, "0\n");
+	} else {
+		fprintf(f, "1\n");
+	}
+
+	fclose(f);
+}
+
+uint8_t GPIO::digitalRead(uint8_t pin)
+{
+	FILE *f;
+	char file[128];
+
+	if (pin > lastPinNum) {
+		return 0;
+	}
+	if (0 == exportedPins[pin]) {
+		pinMode(pin, INPUT);
+	}
+
+	sprintf(file, "/sys/class/gpio/gpio%d/value", pin);
+	f = fopen(file, "r");
+
+	int i;
+	if (fscanf(f, "%d", &i) == EOF) {
+		logError("digitalRead: failed to read pin %u\n", pin);
+		i = 0;
+	}
+	fclose(f);
+	return i;
+}
+
+uint8_t GPIO::digitalPinToInterrupt(uint8_t pin)
+{
+	return pin;
+}
+
+GPIO& GPIO::operator=(const GPIO& other)
+{
+	if (this != &other) {
+		lastPinNum = other.lastPinNum;
+
+		exportedPins = new uint8_t[lastPinNum + 1];
+		for (int i = 0; i < lastPinNum + 1; ++i) {
+			exportedPins[i] = other.exportedPins[i];
+		}
+	}
+	return *this;
+}