Minor px4io optimization

Since this module creates the PX4IO object and that the IOCTL function
doesn't use the file descriptor parameter, there is no need to invoke
IOCTL via the filesystem since we can call it directly.

src/drivers/px4io/px4io.cpp

@@ -1388,7 +1388,8 @@ PX4IO::print_status()
 }
 
 int
-PX4IO::ioctl(file *filep, int cmd, unsigned long arg)
+PX4IO::ioctl(file * /*filep*/, int cmd, unsigned long arg)
+/* Make it obvious that file * isn't used here */
 {
 	int ret = OK;
 
@@ -1668,11 +1669,7 @@ start(int argc, char *argv[])
 	if (param_get(param_find("RC_RL1_DSM_VCC"), &dsm_vcc_ctl) == OK) {
 		if (dsm_vcc_ctl) {
 			g_dev->set_dsm_vcc_ctl(true);
-			int fd = open(GPIO_DEVICE_PATH, O_WRONLY);
-			if (fd < 0)
-				errx(1, "failed to open device");
-			ioctl(fd, DSM_BIND_POWER_UP, 0);
-			close(fd);
+			g_dev->ioctl(nullptr, DSM_BIND_POWER_UP, 0);
 		}
 	}
 	exit(0);
@@ -1681,7 +1678,7 @@ start(int argc, char *argv[])
 void
 bind(int argc, char *argv[])
 {
-	int fd, pulses;
+	int pulses;
 
 	if (g_dev == nullptr)
 		errx(1, "px4io must be started first");
@@ -1699,12 +1696,7 @@ bind(int argc, char *argv[])
 	else 
 		errx(1, "unknown parameter %s, use dsm2 or dsmx", argv[2]);
 
-	fd = open(GPIO_DEVICE_PATH, O_WRONLY);
-
-	if (fd < 0)
-		errx(1, "failed to open device");
-
-	ioctl(fd, DSM_BIND_START, pulses);
+	g_dev->ioctl(nullptr, DSM_BIND_START, pulses);
 
 	/* Open console directly to grab CTRL-C signal */
 	int console = open("/dev/console", O_NONBLOCK | O_RDONLY | O_NOCTTY);
@@ -1721,9 +1713,8 @@ bind(int argc, char *argv[])
 		if (read(console, &c, 1) == 1) {
 			if (c == 0x03 || c == 0x63) {
 				warnx("Done\n");
-				ioctl(fd, DSM_BIND_STOP, 0);
-				ioctl(fd, DSM_BIND_POWER_UP, 0);
-				close(fd);
+				g_dev->ioctl(nullptr, DSM_BIND_STOP, 0);
+				g_dev->ioctl(nullptr, DSM_BIND_POWER_UP, 0);
 				close(console);
 	            exit(0);
             }
@@ -1914,7 +1905,7 @@ px4io_main(int argc, char *argv[])
 			 * We can cheat and call the driver directly, as it
 		 	 * doesn't reference filp in ioctl()
 			 */
-			g_dev->ioctl(NULL, PX4IO_INAIR_RESTART_ENABLE, 1);
+			g_dev->ioctl(nullptr, PX4IO_INAIR_RESTART_ENABLE, 1);
 		} else {
 			errx(1, "not loaded");
 		}
@@ -1958,7 +1949,7 @@ px4io_main(int argc, char *argv[])
 		/* we can cheat and call the driver directly, as it
 		 * doesn't reference filp in ioctl()
 		 */
-		int ret = g_dev->ioctl(NULL, PX4IO_SET_DEBUG, level);
+		int ret = g_dev->ioctl(nullptr, PX4IO_SET_DEBUG, level);
 		if (ret != 0) {
 			printf("SET_DEBUG failed - %d\n", ret);
 			exit(1);