Re: [PATCH RFT] driver core: faux: allow to set the firmware node for a faux device

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

On Fri, Mar 06, 2026 at 03:07:03PM +0100, Bartosz Golaszewski wrote:
> On Fri, Mar 6, 2026 at 2:54 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Fri, Mar 06, 2026 at 02:45:56PM +0100, Bartosz Golaszewski wrote:
> > > Add a new variant of faux_device_create() taking a firmware node handle
> > > as argument and attaching it to the created faux device. This allows
> > > users to define and read device properties using the standard property
> > > accessors.
> >
> > Why would a faux device have firmware backing?  Doesn't that mean it
> > should be a platform device?
> >
> > > While at it: order includes in faux.c alphabetically for easier
> > > maintenance.
> >
> > Hint, that should be a separate patch, and is never something that I
> > enforce or require in .c files I maintain :)
> >
> > > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> > > ---
> > > Hi Shivendra et al!
> > >
> > > This patch is related to my response to your reboot-mode patch[1].
> > >
> > > You should be able to use the new function like:
> > >
> > >   faux_device_create_full("psci-reboot-mode", NULL, NULL, NULL, of_fwnode_handle(np));
> >
> > What is the fwnode handle here for?  Why is it required at all?  What
> > resources are involved that would want this?
> >
> 
> Shivendra creates a faux device that registers with the reboot-mode
> subsystem which reads the reboot-mode definitions from devicetree. The
> faux device needs to have the "reboot-mode" OF-node attached. In his
> current proposal, Shivenda had to bypass faux device's probe() because
> he can't have the fwnode attached before probe() is called.

Why would a firmware device be attached to a faux device?  A firmware
device is, implicitly, already part of the firmware "device tree", so
there should be something for it to be a child of already in the system.

thanks,

greg k-h