On Tue, Nov 30, 2021 at 07:32:28PM +0100, Bartosz Golaszewski wrote:

On Tue, Nov 30, 2021 at 5:20 PM Andy Shevchenko
[off-list ref] wrote:

quoted

On Tue, Nov 30, 2021 at 06:14:01PM +0200, Andy Shevchenko wrote:

quoted

On Tue, Nov 30, 2021 at 04:41:23PM +0100, Bartosz Golaszewski wrote:

...

quoted

Not sure I understand the proposal. Can you provide couple of (simplest)
examples?

And also it sounds like reinventing a wheel. What problem do you have that you
need to solve this way?

Have you seen these:
        drivers/gpio/gpio-dwapb.c
        drivers/mfd/intel_quark_i2c_gpio.c
?

GPIO driver has a main (controller level) node along with children on per bank
basis. Currently it works with the provided approach (see second driver).

Yep, I know dwapd. What happens in probe is that each bank device is
created using the properties from the associated child fwnode but the
parent device's fwnode is actually assigned as the gpiochip's fwnode.

The first device is the physical device of the GPIO controller,
the

   ,-> fwnode of the physical device
   |
  GPIO  -> portA -> gpiodev A (child fwnode A)
       `-> portB -> gpiodev B (child fwnode B)
           ...

This is logically wrong

I don't see how, it represents hardware as is.

and OF doesn't do it - it assigns the child
of_node to the child device if gpio_chip->of_node is assigned in the
driver.

And this is exactly what happens.

I'm not sure if ACPI does this.

Depending on the device description. In the case of dwapb on Galileo platform
the ACPI just misses that, that's why board files (see second driver).

Non-OF drivers don't have a way to do this and this patch enables it.

You meant non-FW drivers, right? How come? What am I missing?

I don't see the issue here. When user wants to have GPIO device, first we
instantiate it with its own fwnode (in your case swnode), followed by
additional (child) swnode per bank.

I want to add it mostly because gpio-sim can then use the software
node to identify the device in the configfs by that software node but
IMO this is logically correct too.

I also think so.

-- 
With Best Regards,
Andy Shevchenko