Re: [PATCH v2] pinctrl-tegra: Add config property GPIO mode

From: Thierry Reding
Date: Thu Jan 23 2025 - 04:01:36 EST


On Fri, Dec 20, 2024 at 02:51:43PM +0100, Linus Walleij wrote:
> Hi Prathamesh,
>
> thanks for your patch!
>
> a question here:
>
> On Tue, Dec 17, 2024 at 4:33 PM Prathamesh Shete <pshete@xxxxxxxxxx> wrote:
>
> > The SFIO/GPIO select bit is a crucial part of Tegra's pin multiplexing
> > system:
> > - When set to 1, the pin operates in SFIO mode, controlled by the
> > pin's assigned special function.
> > - When set to 0, the pin operates as a general-purpose GPIO.
> >
> > This SFIO/GPIO select bit that is set for a given pin is not displayed,
> > adding the support to retrieve this information from the
> > pinmux set for each pin.
> >
> > Signed-off-by: Prathamesh Shete <pshete@xxxxxxxxxx>
>
> If the description is correct, why is this bit not unconditionally
> set in
> tegra_pinctrl_gpio_request_enable()
> and unconditionally cleared in
> tegra_pinctrl_gpio_disable_free()
> ?

Sorry for the late reply. This bit is already being set during
.gpio_request_enable() and .gpio_disable_free(). My understanding is
that this patch is primarily for making this available in debugfs. I
suppose we could make that clearer by not making this part of the
standard pinconfig options, but rather put it into a "read-only" set
configs?

Thierry

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