Re: [PATCH] software node: allow referencing software nodes by name

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Mar 23, 2026 at 09:46:50PM -0700, Dmitry Torokhov wrote:
> Currently static device properties references require either an
> instance of software node or an instance of fwnode_handle to be
> available when defining a reference property. This may not be very
> convenient when device node is instantiated from a different module
> (which is usually the case).
> 
> The original implementation for describing GPIOs using software nodes
> worked around this by creating a detached from gpiochip instances
> software nodes, and performing matching using gpiochip label and node
> name. The gpiolib maintainers rightfully questioned this approach, and
> currently recommend to attach secondary software node to gpiochip
> instance, export the symbol, and use it in board file when instantiating
> static properties. This unfortunately results in tight coupling between
> gpiochip drivers and board code, necessitates creation of header files,
> requires adding Kconfig dependencies, limits options for choosing module
> vs built-in compilation, and alters device initialization/probing order.
> 
> Solve the issue by providing an option to use software node name in
> place of the node instance when describing reference properties. When
> evaluating reference driver core will attempt to resolve the name to
> concrete node instance and, in case of GPIO references, will use
> identity match on firmware node to locate corresponding gpiochip device.
> 
> This approach has a drawback of needing to know name of the node that
> gpiochip device will be using, however benefits (minimal coupling, no
> need for adding dependencies) outweigh this drawback.
> 
> To deal cases with software nodes not being created or registered at
> time of look up, assume that the node with matching name will get
> registered eventually and return -EPROBE_DEFER in the meantime.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
>  drivers/base/swnode.c    | 25 +++++++++++++++++++------
>  include/linux/property.h |  4 ++++
>  2 files changed, 23 insertions(+), 6 deletions(-)

Do you have a follow-on patch that uses this new api anywhere?

thanks,

greg k-h