On Wed, May 29, 2024 at 12:48 PM Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > On Wed, May 29, 2024 at 09:16:43AM +0300, Andy Shevchenko wrote: > > On Tue, May 28, 2024 at 11:20 PM Laurent Pinchart wrote: > > > On Tue, May 28, 2024 at 10:36:06PM +0300, Andy Shevchenko wrote: ... > > > > > + device_set_of_node_from_dev(dev, dev->parent); > > > > > > > > Why not device_set_node()? > > > > > > Because device_set_of_node_from_dev() is meant for this exact use case, > > > where the same node is used for multiple devices. It also puts any > > > previous dev->of_node, ensuring proper refcounting when devices are > > > unbound and rebound, without being deleted. > > > > When will the refcount be dropped (in case of removal of this device)? > > Or you mean it shouldn't? > > Any refcount taken on the OF node needs to be dropped. The device core > only drops the refcount when the device is being deleted, not when > there's an unbind-rebind cycle without deletion of the device (as > happens for instance when the module is unloaded and reloaded). Under "device" you meant the real hardware, as Linux device (instance of the struct device object) is being rebuilt AFAIK)? > This has > to be handled by the driver. device_set_of_node_from_dev() handles it. But why do you need to keep a parent node reference bumped? Only very few drivers in the kernel use this API and I believe either nobody knows what they are doing and you are right, or you are doing something which is not needed. -- With Best Regards, Andy Shevchenko
