Messages in this thread | | | Subject | Re: [Q] devicetree overlays | From | "Enrico Weigelt, metux IT consult" <> | Date | Wed, 12 Aug 2020 15:27:47 +0200 |
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On 07.08.20 16:17, Sven Van Asbroeck wrote:
Hi,
> I believe you're asking: "how do I associate device tree nodes to > devices on a dynamically discoverable bus such as USB or PCI" right ? > > I believe that already exists. You can describe the _expected_ pci or > usb topology in the > devicetree. If a device gets detected in a spot on the bus described > in the tree, that > snippet will be automatically associated with this device. > > How to for usb: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/usb/usb-device.txt?h=v5.8 > > How to for pci: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/pci/pci.txt?h=v5.8
Thanks, that looks good.
But I've still got another problem: how can I use DT along w/ ACPI ?
The scenario goes like this:
* machine boots and probes normally w/ ACPI * device is detected via USB, PCI, DMI, etc -> driver gets active * driver loads (or carries) a DT snippet * devices on the bus are instantiated via this DT snippet
(driver could also be some udev vodoo)
Example a:
* generic usb i2c dongle w/ some i2c devices attached behind it * config (or DT snippet) somewhere in the FS
Example b:
* x86 board driver (eg. apu2/3/4), probed via DMI * just instantiates a bunch of generic drivers and wires up devices (gpio, leds, keys, ...)
Do you think we can already do that ? Otherwise, what has to be done to achieve that ?
--mtx
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