GPIO: Fix Button detection

[bennetleins]

Currently only LEDs are detected and added automatically. This commit adds the capabilities for Buttons as well.

[bennetleins]

Any chance you could take a look at this @pkoscik ?

[pkoscik]

Hello @bennetleins! Thanks for your contribution.

There seems to be an issue in the way interrupt connections are handled for buttons.

Using this (Nucleo F446ZE) Devicetree file and dts2repl from your PR results in the following snippet:

...

gpioc: GPIOPort.STM32_GPIOPort @ sysbus <0x40020800, +0x400>

userbutton: Miscellaneous.Button @ gpioc 0xd
    invert: true

gpioc:
    13 -> userbutton@0

...

This is incorrect: the interrupts are connected in reverse (sink to source). Instead, it should generate the following snippet:

...

gpioc: GPIOPort.STM32_GPIOPort @ sysbus <0x40020800, +0x400>

userbutton: Miscellaneous.Button @ gpioc 0xd
    invert: true

userbutton:
    -> gpioc@13

...

For reference PTAL at a GPIO description for a similar Nucleo board in the Renode tree.

[bennetleins]

I just changed the code to fix the issue with the interrupt connections. If I run the code on the nucleo hello_world I now get this:

...
gpioc: GPIOPort.STM32_GPIOPort @ sysbus <0x40020800, +0x400>
...
userbutton: Miscellaneous.Button @ gpioc 0xd
    invert: true
    -> userbutton@13
...