Re: [PATCH V3 1/3] gpio: Add virtio-gpio driver

[Enrico Weigelt, metux IT consult]

On 10.06.21 15:22, Arnd Bergmann wrote:

> Can you give an example of how this would be hooked up to other drivers
> using those gpios. Can you give an example of how using the "gpio-keys" or
> "gpio-leds" drivers in combination with virtio-gpio looks like in the DT?

Connecting between self-probing bus'es and DT is generally tricky. IMHO
we don't have any generic mechanism for that.

I've made a few attempts, but nothing practically useful, which would be
accepted by the corresponding maintainers, yet. We'd either need some
very special logic in DT probing or pseudo-bus'es for the mapping.
(DT wants to do those connections via phandle's, which in turn need the
referenced nodes to be present in the DT).

>  From what I can tell, both the mmio and pci variants of virtio can have their
> dev->of_node populated, but I don't see the logic in register_virtio_device()
> that looks up the of_node of the virtio_device that the of_gpio code then
> tries to refer to.

Have you ever successfully bound a virtio device via DT ?


--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
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