Make it possible to run fmu and px4io simultaneously with full control over both sets of possible PWM outputs. First started wins.

apps/drivers/device/cdev.cpp

@@ -74,7 +74,7 @@ static int	cdev_poll(struct file *filp, struct pollfd *fds, bool setup);
  * Note that we use the GNU extension syntax here because we don't get designated
  * initialisers in gcc 4.6.
  */
-static const struct file_operations cdev_fops = {
+const struct file_operations CDev::fops = {
 open	: cdev_open,
 close	: cdev_close,
 read	: cdev_read,
@@ -118,7 +118,7 @@ CDev::init()
 		goto out;
 
 	// now register the driver
-	ret = register_driver(_devname, &cdev_fops, 0666, (void *)this);
+	ret = register_driver(_devname, &fops, 0666, (void *)this);
 
 	if (ret != OK)
 		goto out;

apps/drivers/device/device.h

@@ -286,6 +286,12 @@ public:
        bool            is_open() { return _open_count > 0; }
 
 protected:
+	/**
+	 * Pointer to the default cdev file operations table; useful for
+	 * registering clone devices etc.
+	 */
+	static const struct file_operations	fops;
+
 	/**
 	 * Check the current state of the device for poll events from the
 	 * perspective of the file.