Messages in this thread | | | Subject | Re: [PATCH/RFC 1/4]device core changes | From | Li Shaohua <> | Date | Tue, 09 Nov 2004 08:50:18 +0800 |
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On Tue, 2004-11-09 at 06:58, Greg KH wrote: > On Mon, Nov 08, 2004 at 12:11:11PM +0800, Li Shaohua wrote: > > Hi, > > This is the device core change required. Add .platform_bind method for > > bus_type, so platform can do addition things when add a new device. A > > case is ACPI, we want to utilize some ACPI methods for physical devices. > > 1. Why doesn't use 'platform_notify'? > > Current device core has a 'platform_notify' mechanism, but it's not > > sufficient for this. Only sepcific bus type know how to parse dev.bus_id > > and know how to encode specific device's address into ACPI _ADR syntax. > > I don't see why platform_notify is not sufficient. This is the exact > reason it was added to the code. As I said in the email, we need know the bus type to decode and encode address. If you use platform_notify, you must do something like this: switch (dev->bus) { case pci_bus_type: bind PCI devices with ACPI devices break; case ide_bus_type: bind IDE devices with ACPI devices break; .... } But note this method requires all bus types are build-in. If a bus type is in a loadable module (such as IDE bus), the method will failed. I searched current tree, only ARM implemented 'platform_notify', but ARM only cares PCI bus, ACPI cares about all bus types. > > > 2. Why adds new 'handle' in 'struct device'? > > 'Platform_data' is the best candidate, but a search shows some drivers > > have used it. We can remove 'handle' after the drivers changes their > > behavior. > > No, fix the drivers. Don't add something that you are going to remove > later. Ok, I'll try to fix them.
Thanks, Shaohua
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