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

[Viresh Kumar <viresh.kumar@xxxxxxxxxx>]

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?
> 
> Would qemu simply add the required DT properties to the device node that
> corresponds to the virtio device in this case?
> 
> 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.

To be honest, I haven't tried this yet and I was expecting it to be
already taken care of. I was relying on the DTB automatically
generated by Qemu to get the driver probed and didn't have a look at
it as well.

I now understand that it won't be that straight forward. The same must
be true for adding an i2c device to an i2c bus over virtio (The way I
tested that earlier was by using the sysfs file to add a device to a
bus).

This may be something lacking generally for virtio-pci thing, not
sure though.

-- 
viresh