linux-kernel - [BUG ?] regmap: debugfs: WARN

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Date:	Sat, 13 Jun 2015 15:21:02 +0200
From:	Sergej Sawazki <ce3a@....de>
To:	broonie@...nel.org, gregkh@...uxfoundation.org,
	w.sang@...gutronix.de, wsa@...-dreams.de
CC:	linux-kernel@...r.kernel.org
Subject: [BUG ?] regmap: debugfs: WARN_ON at regmap-debugfs.c:151

Hello all,

when I try to read the register values of a i2c ASoC codec through
debugfs, (eg: cat /sys/kernel/debug/regmap/1-001a/registers)
I am getting an WARN_ON at drivers/base/regmap/regmap-debugfs.c:151.
Please see attached dmesg.txt for details.

I did some debugging and found that regmap_readable(), at regmap-
debugfs.c:109, returns "false" for all registers, hence the 
debugfs_off_cache list remains empty and we get an warning in line 151.

Reverting commit 4191f1979 "regmap: if format_write is used, declare
all registers as "unreadable"" fixed the issue.

Regards,
Sergej

View attachment "dmesg.txt" of type "text/plain" (1572 bytes)