Inicializacny commit

gpiosysfs.c

@@ -0,0 +1,85 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#include <errno.h>
+#include <stdio.h>          /* printf(), snprintf() */
+#include <stdlib.h>         /* strtol(), exit() */
+#include <sys/types.h> 
+#include <time.h>
+#include <errno.h>  
+#include "gpiosysfs.h"
+
+static void writeToFile(const char *absoluteFileName, const char *contents) {
+	int fd = open(absoluteFileName, O_WRONLY);
+
+	if (-1 == fd) {
+		fprintf(stderr, "Couldn't open %s for writing!\n", absoluteFileName);
+		exit(1);
+	}
+
+	int contentsLength = strlen(contents);
+
+	if (write(fd, contents, contentsLength) != contentsLength) {
+		fprintf(stderr, "Failed to write entire value %s to %s!\n", contents, absoluteFileName);
+		close(fd);
+		exit(1);
+	}
+
+	close(fd);
+}
+
+void gpioSetup(const char *pin) {
+	// TODO only export if not already exported...
+	if (access("/sys/class/gpio/unexport",W_OK) == 0) 
+		writeToFile("/sys/class/gpio/unexport", pin);
+	writeToFile("/sys/class/gpio/export", pin);
+
+	char buf[33];
+	struct stat statBuf;
+	int pinExported = -1;
+
+	sprintf(buf, "/sys/class/gpio/gpio%s/direction", pin);
+
+	// May have to briefly wait for OS to make symlink! 
+	while (pinExported != 0) {	
+		msleep(1000);
+		pinExported = stat(buf, &statBuf);
+	}
+
+	writeToFile(buf, "out");
+}
+
+void gpioCleanup(const char *pin) {
+	writeToFile("/sys/class/gpio/unexport", pin);
+}
+
+void gpioWrite(const char *pin, const char *val) {
+	char buf[29];
+	sprintf(buf, "/sys/class/gpio/gpio%s/value", pin);
+	writeToFile(buf, val);
+}  
+
+/* msleep(): Sleep for the requested number of milliseconds. */
+int msleep(long msec)
+{
+    struct timespec ts;
+    int res;
+
+    if (msec < 0)
+    {
+        errno = EINVAL;
+        return -1;
+    }
+
+    ts.tv_sec = msec / 1000;
+    ts.tv_nsec = (msec % 1000) * 1000000;
+
+    do {
+        res = nanosleep(&ts, &ts);
+    } while (res && errno == EINTR);
+
+    return res;
+}