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From: Russell King - ARM Linux admin <>
To: Jacek Anaszewski <>,
	Linus Walleij <>,
	Pavel Machek <>
Subject: "leds: gpio: Use generic support for composing LED names" breaks gpio debugfs
Date: Wed, 4 Dec 2019 11:02:19 +0000
Message-ID: <> (raw)


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, 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 is now NULL prior to the call to

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?


RMK's Patch system:
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to 11.9Mbps down 500kbps up

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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 ` Jacek Anaszewski
2019-12-04 23:45   ` Linus Walleij
2019-12-05 21:29     ` Jacek Anaszewski

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