kernel-devel/chardev: added example

kernel and userspace example, for open, close, read, write

TODO: implement read, write

Signed-off-by: Manuel Traut <manut@linutronix.de>

2 files changed, 34 insertions, 0 deletions

diff --git a/kernel-devel/char-device/example/user/Makefile b/kernel-devel/char-device/example/user/Makefile
new file mode 100644
index 0000000..66a330c
--- /dev/null
+++ b/kernel-devel/char-device/example/user/Makefile
@@ -0,0 +1,6 @@
+OBJECTS=huhu.o
+
+all: $(OBJECTS)
+	gcc -o huhu $(OBJECTS)
+clean:
+	rm -f $(OBJECTS) huhu
diff --git a/kernel-devel/char-device/example/user/huhu.c b/kernel-devel/char-device/example/user/huhu.c
new file mode 100644
index 0000000..e86c126
--- /dev/null
+++ b/kernel-devel/char-device/example/user/huhu.c
@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+int main (int argc, char **argv)
+{
+	int ret = 0;
+	FILE *fp;
+
+	fp = fopen ("/dev/huhu", "r+");
+	if (!fp)
+	{
+		perror ("open /dev/huhu failed");
+		ret = errno;
+		goto out;
+	}
+
+	system ("/bin/lsmod | grep huhu");
+
+	ret = fclose (fp);
+	if (ret)
+	{
+		perror ("close /dev/huhu failed");
+		goto out;
+	}
+out:
+	return ret;
+}