On Wed, 2013-10-02 at 16:40 -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > On Wed, Oct 02, 2013 at 04:35:15PM -0500, Scott Wood wrote: > > On Wed, 2013-10-02 at 14:16 -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > > On Wed, Oct 02, 2013 at 04:08:41PM -0500, Scott Wood wrote: > > > > I don't see any equivalent functionality to PCI_ANY_ID for platform > > > > devices. > > > > > > Nor should it. If you are wanting to bind platform devices to different > > > things based on "ids" or "strings" or something else, then you had > > > better not be using a platform device because that is not what you have > > > anymore. > > > > I don't see how anything could be considered a platform device under > > your definition. > > Devices that you just "know" are at a specific memory location ahead of > time. > > > Even before all the device tree stuff came along, > > platform devices were still bound based on strings. > > Not all of them, there are lots that are not, look at ISA devices on a > PC platform for one example (your pc speaker, keyboard controller, > etc.) Using platform devices to let board files provide this information to driver files was a big improvement over hacking up the drivers directly to know about all sorts of different boards/SoCs. Once you split that knowledge into a different place you need a way of matching the two. BTW, this is done with the pc speaker as far as I can tell -- arch/x86/kernel/pcspeaker.c registers a device using the string "pcspkr" (as do some non-PC platforms). > > And even if we did still have a separate OF platform bus, my point about > > there not being a wildcard match applies to of_device_id as well. It > > certainly is not the case that "this is already there, and has been for > > years with no problems". > > That's an OF problem then, feel free to fix it there, but not in the > driver core with a crazy "ignore this bus type string" hack :) Even if we did this for OF and ACPI, you'd still have a problem if you want to use VFIO with a platform device that only has plain old platform data; thus, the platform bus (not driver core) seems to be the appropriate place for a wildcard match if we end up needing it. It may be moot though, since for platform devices we may want explicit kernel support for a device even with vfio, in order to reset/quiesce it between users. What it looks like we do still want from the driver core is the ability for a driver to say that it should not be bound to a device except via explicit sysfs bind, and the ability for a user to say that a device should not be bound to a driver except via explicit sysfs bind. This is a separate issue from making driver_match_device() happy (in some earlier e-mails in the thread these two issues were not properly separated). -Scott -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
