On Mon, Jan 23, 2023 at 04:32:55PM +0100, Lee Jones wrote: > On Mon, 23 Jan 2023, Vincent Whitchurch wrote: > > Add a PCI driver which registers all child nodes specified in the > > devicetree. It will allow platform devices to be used on virtual > > systems which already support PCI and devicetree, such as UML with > > virt-pci. > > > > The driver has no id_table by default; user space needs to provide one > > using the new_id mechanism in sysfs. > > This feels wrong for several reasons. > > Firstly, I think Greg (Cc:ed) will have something to say about this. > > Secondly, this driver does literally nothing. Well, it does do what the commit message says. If there's another way of accomplishing that, I'm all ears. > Why can't you use of of the other, pre-existing "also register my > children" compatibles? > > See: drivers/bus/simple-pm-bus.c > drivers/of/platform.c simple-pm-bus registers a platform driver, and drivers/of/platform.c works on the platform bus. The driver added by this patch is a PCI driver. So I don't understand how the files you mention could be used here? In case it helps, the relevant nodes in my UML devicetree look something like this: virtio@2 { compatible = "virtio,uml"; virtio-device-id = <1234>; ranges; pci { #address-cells = <3>; #size-cells = <2>; ranges = <0x0000000 0 0 0 0xf0000000 0 0x20000>; compatible = "virtio,device4d2", "pci"; device_type = "pci"; bus-range = <0 0>; platform_parent: device@0,0 { compatible = "pci494f,dc8"; reg = <0x00000 0 0 0x0 0x10000>; ranges; uart@10000 { compatible = "google,goldfish-tty"; reg = <0x00000 0 0x10000 0 0x10000>; }; }; }; };