linux-kernel - Re: [PATCH RFC v2 4/7] pinctrl-scmi: add PIN_CONFIG_INPUT

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Message-ID: <CACRpkdZ9EHoHiKit+T-ur0xDKMEoN_=TydzTfoggNBQGdra2bQ@mail.gmail.com>
Date: Fri, 5 Sep 2025 10:27:12 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: Sudeep Holla <sudeep.holla@....com>, AKASHI Takahiro <takahiro.akashi@...aro.org>, 
	Michal Simek <michal.simek@....com>, Cristian Marussi <cristian.marussi@....com>, 
	arm-scmi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC v2 4/7] pinctrl-scmi: add PIN_CONFIG_INPUT_VALUE

On Sun, Jul 20, 2025 at 9:39 PM Dan Carpenter <dan.carpenter@...aro.org> wrote:

> In SCMI the value of the pin is just another configuration option.  Add
> this as an option in the pin_config_param enum and creating a mapping to
> SCMI_PIN_INPUT_VALUE in pinctrl_scmi_map_pinconf_type()
>
> Since this is an RFC patch, I'm going to comment that I think the SCMI
> pinctrl driver misuses the PIN_CONFIG_OUTPUT enum.  It should be for
> enabling and disabling output on pins which can serve as both input and
> output.  Enabling it is supposed to write a 1 and disabling it is
> supposed to write a 0 but we use that side effect to write 1s and 0s.  I
> did't change this because it would break userspace but I'd like to add a
> PIN_CONFIG_OUTPUT_VALUE enum as well and use that in the GPIO driver.
> But in this patchset I just use PIN_CONFIG_OUTPUT.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>

I tweaked this patch around a bit and applied: removed the second comment
in the commit message and wrote the docs to be more generic since
in the future other things than SCMI might want to use this
config option.

Yours,
Linus Walleij