Re: [PATCH v1 1/1] Add driver for Mellanox BlueField-3 GPIO controller

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Thu, May 12, 2022 at 10:45 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:

>> > All GPIOs are always controlled by HW by default.
>> > FW_CONTROL_SET is used when we want to release control of the GPIO by
>> > HW and give the control to software instead.
>>
>> What does that mean in practice? What way does hardware control a GPIO?
>>
>> It's not some way of remuxing the pins is it, so you what you are calling
>> "controlled by hardware" is actually that it is controlled by e.g. I2C and
>> other stuff that may be muxed in?
>
> Yes exactly. These GPIO pins are already assigned a specific HW
> functionality like I2C SDA/SCL, MDIO etc... but we would like to
> support the option to control them from software if desired.

But how does that play with your pin controller?

I mean: is the multiplexing of different other devices also software
controlled, so this should have a proper pin control driver rather
than just a GPIO driver?

Yours,
Linus Walleij