Hi Rob, On Fri, 27 Jun 2025 10:52:00 -0500 Rob Herring <robh@xxxxxxxxxx> wrote: > On Fri, Jun 13, 2025 at 03:47:45PM +0200, Herve Codina wrote: > > The simple-pm-bus driver handles several simple busses. When it is used > > with busses other than a compatible "simple-pm-bus", it doesn't populate > > its child devices during its probe. > > > > This confuses fw_devlink and results in wrong or missing devlinks. > > > > Once a driver is bound to a device and the probe() has been called, > > device_links_driver_bound() is called. > > > > This function performs operation based on the following assumption: > > If a child firmware node of the bound device is not added as a > > device, it will never be added. > > > > Among operations done on fw_devlinks of those "never be added" devices, > > device_links_driver_bound() changes their supplier. > > > > With devices attached to a simple-bus compatible device, this change > > leads to wrong devlinks where supplier of devices points to the device > > parent (i.e. simple-bus compatible device) instead of the device itself > > (i.e. simple-bus child). > > > > When the device attached to the simple-bus is removed, because devlinks > > are not correct, its consumers are not removed first. > > > > In order to have correct devlinks created, make the simple-pm-bus driver > > compliant with the devlink assumption and create its child devices > > during its probe. > > IIRC, skipping child nodes was because there were problems with > letting the driver handle 'simple-bus'. How does this avoid that now? I don't know about the specific issues related to those problems. Do you have some pointers about them? > > The root of_platform_populate() that created the simple-bus device that > gets us to the probe here will continue descending into child nodes. > Meanwhile, the probe here is also descending into those same child > nodes. Best case, that's just redundant. Worst case, won't you still > have the same problem if the first of_platform_populate() creates the > devices first? > Maybe we could simply avoid of_platform_populate() to be recursive when a device populate by of_platform_populate() is one of devices handled by the simple-bus driver and let the simple-bus driver do the job. of_platform_populate will handle the first level. It will populate children of the node given to of_platform_populate() and the children of those children will be populate by the simple-bus driver. I could try a modification in that way. Do you think it could be a correct solution? Best regards, Hervé
