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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Pavel Machek <pavel@ucw.cz>
Cc: linux-arm-kernel@lists.infradead.org, linux-leds@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: "leds: gpio: Use generic support for composing LED names" breaks gpio debugfs
Date: Wed, 4 Dec 2019 11:02:19 +0000	[thread overview]
Message-ID: <20191204110219.GV25745@shell.armlinux.org.uk> (raw)

Hi,

Patch d7235f5feaa0 ("leds: gpio: Use generic support for composing LED
names") changed the way labels are used.

devm_fwnode_get_gpiod_from_child() is passed led.name, which used to be
set to the label or node name, resulting in /sys/kernel/debug/gpio
containing useful information.  For example:

 gpio-487 (                    |udpu:green:power    ) out lo
 gpio-488 (                    |udpu:red:power      ) out hi
 gpio-489 (                    |udpu:green:network  ) out hi
 gpio-490 (                    |udpu:red:network    ) out hi
 gpio-491 (                    |udpu:green:alarm    ) out hi
 gpio-492 (                    |udpu:red:alarm      ) out hi

After this commit, it now contains a rather less useful:

 gpio-487 (                    |?                   ) out hi ACTIVE LOW
 gpio-488 (                    |?                   ) out hi ACTIVE LOW
 gpio-489 (                    |?                   ) out hi ACTIVE LOW
 gpio-490 (                    |?                   ) out hi ACTIVE LOW
 gpio-491 (                    |?                   ) out hi ACTIVE LOW
 gpio-492 (                    |?                   ) out hi ACTIVE LOW

This is because led.name is now NULL prior to the call to
devm_fwnode_get_gpiod_from_child().

While this is not an API, it is useful for debugging, and given the
dynamic allocation of GPIOs to physical GPIOs, having the labels
present is an advantage.

Can this be fixed / old behaviour restored?

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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             reply	other threads:[~2019-12-04 11:02 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-04 11:02 Russell King - ARM Linux admin [this message]
2019-12-04 20:52 ` "leds: gpio: Use generic support for composing LED names" breaks gpio debugfs Jacek Anaszewski
2019-12-04 23:45   ` Linus Walleij
2019-12-05 21:29     ` Jacek Anaszewski

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