diff --git a/ioc/lw35-tool/main.c b/ioc/lw35-tool/main.c
new file mode 100644
index 0000000..be75e45
--- /dev/null
+++ b/ioc/lw35-tool/main.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <string.h>
+#include <stropts.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#define IOCTL_SET_MODE 42
+enum lw35ioc_state {PASSIVE = 0, PROG_KBD, PROG_PRI, BYPASS, ACTIVE, STATE_COUNT};
+
+int f;
+
+static void help(int argc, char *argv[])
+{
+	fprintf(stderr,
+		"usage: %s <command>\n\n"
+		"  command: set-mode <mode>\n"
+		"       mode: passive, active, rfu-kbd, rfu-pri, bypass\n",
+		argv[0]);
+}
+
+static int set_mode(int argc, char *argv[])
+{
+	int mode = -1;
+	
+	if (argc < 3) {
+		help(argc, argv);
+		return 10;
+	}
+	
+	if (!strcmp(argv[2], "passive"))
+		mode = PASSIVE;
+	else if (!strcmp(argv[2], "rfu-kbd"))
+		mode = PROG_KBD;
+	else if (!strcmp(argv[2], "rfu-pri"))
+		mode = PROG_PRI;
+	else if (!strcmp(argv[2], "bypass"))
+		mode = BYPASS;
+	else if (!strcmp(argv[2], "active"))
+		mode = ACTIVE;
+		
+	if (mode == -1) {
+		fprintf(stderr, "Error: Invalid mode.\n");
+		return 10;
+	}
+	
+	ioctl(f, IOCTL_SET_MODE, mode);
+	
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc < 2) {
+		help(argc, argv);
+		return 1;
+	}
+	
+	f = open("/dev/lw35", O_RDWR);
+	if (f == -1) {
+		fprintf(stderr, "Error opening lw35ioc device.\n");
+		return 3;
+	}
+	
+	if (!strcmp(argv[1], "set-mode")) {
+		ret = set_mode(argc, argv);
+	} else {
+		fprintf(stderr, "Unknown command.\n");
+		ret = 2;
+	}
+	
+	close(f);
+	
+	return ret;
+}