Re: [PATCH v2 1/2] dt-bindings: gpio: add SAMA5D2 PIOBU support

[<Andrei.Stefanescu@microchip.com>]

Hello Rob,

Thank you for your feedback.

I will add a bit of context regarding the secumod. The 
"atmel,sama5d2-secumod"
compatible string is not used for loading a driver. It is used by atmel 
securam
driver (drivers/misc/sram.c) which has access to secumod's registers via:

     syscon_regmap_lookup_by_compatible("atmel,sama5d2-secumod")

So the secumod exports multiple hardware functions, eg: the securam, the 
PIOBU
pins which can be used as GPIO pins.

My initial patch had the "microchip,sama5d2-piobu" compatible appended 
to the
secumod's compatible e.g.:

secumod@fc040000 {
     compatible = "syscon", "microchip,sama5d2-piobu";
...

Taking into consideration Linus Walleij's advice I arrived to the current
version. I thought this was a good idea because it separates the secumod 
node
from the GPIO controller node. Please notice that securam node is already
separated from secumod node (it is a separate node in the device tree).

I have a few questions because I am not sure of the best approach:

1. Is it ok to have the GPIO controller as a child node?
2. I used simple-mfd because it was the only way I could think of in 
order to
    get the driver probed.
3. Should I add a register range? I thought that because the driver uses 
syscon
    it is not necessary to add the register range. Also, the register 
range would
    have been a subset of the secumod's register range.