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

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Thu, May 5, 2022 at 7:01 PM Asmaa Mnebhi <asmaa@xxxxxxxxxx> wrote:

>> Why isn't FW_CONTROL_CLEAR/SET used when making  a line into an output?
>> Seems unsymmetric? At least put a comment in the code why this is different from
>> making a line into input.
>
> Ok I will add a comment.
>
> 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?

Yours,
Linus Walleij