linux-kernel - Re: [RFC/RFT PATCH] pinctrl: bcm2835: don't -EINVAL on alternate funcs from get

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Message-ID: <Z7XqSVfhPGI5J63B@finisterre.sirena.org.uk>
Date: Wed, 19 Feb 2025 14:27:21 +0000
From: Mark Brown <broonie@...nel.org>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Linus Walleij <linus.walleij@...aro.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Ray Jui <rjui@...adcom.com>, Scott Branden <sbranden@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Stefan Wahren <wahrenst@....net>, Liao Chen <liaochen4@...wei.com>,
	Chen-Yu Tsai <wens@...e.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	linux-gpio@...r.kernel.org, linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [RFC/RFT PATCH] pinctrl: bcm2835: don't -EINVAL on alternate
 funcs from get_direction()

On Wed, Feb 19, 2025 at 11:27:50AM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> Since commit 9d846b1aebbe ("gpiolib: check the return value of
> gpio_chip::get_direction()") we check the return value of the
> get_direction() callback as per its API contract. This driver returns
> -EINVAL if the pin in question is set to one of the alternative
> (non-GPIO) functions. This isn't really an error that should be
> communicated to GPIOLIB so default to returning the "safe" value of
> INPUT in this case. The GPIO subsystem does not have the notion of
> "unknown" direction.

I see this was already tested for these specific boards.  I've also
found that Avenger96 is failing with bisect pointing to the same commit
this is fixing:

    https://lava.sirena.org.uk/scheduler/job/1126314

as is the Libretech Potato:

    https://lava.sirena.org.uk/scheduler/job/1126285

neither of which produce any output before dying, they'll not be fixed
by this change.  Seems like an audit of the drivers might be in order?

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