macintosh: therm_windtunnel: fix regression when instantiating devices
authorWolfram Sang <wsa@the-dreams.de>
Tue, 25 Feb 2020 14:12:29 +0000 (15:12 +0100)
committerWolfram Sang <wsa@the-dreams.de>
Sat, 29 Feb 2020 20:13:22 +0000 (21:13 +0100)
commit38b17afb0ebb9ecd41418d3c08bcf9198af4349d
tree4007a8cc82228efe42c4c06386a22be45e0338a0
parent54498e8070e19e74498a72c7331348143e7e1f8c
macintosh: therm_windtunnel: fix regression when instantiating devices

Removing attach_adapter from this driver caused a regression for at
least some machines. Those machines had the sensors described in their
DT, too, so they didn't need manual creation of the sensor devices. The
old code worked, though, because manual creation came first. Creation of
DT devices then failed later and caused error logs, but the sensors
worked nonetheless because of the manually created devices.

When removing attach_adaper, manual creation now comes later and loses
the race. The sensor devices were already registered via DT, yet with
another binding, so the driver could not be bound to it.

This fix refactors the code to remove the race and only manually creates
devices if there are no DT nodes present. Also, the DT binding is updated
to match both, the DT and manually created devices. Because we don't
know which device creation will be used at runtime, the code to start
the kthread is moved to do_probe() which will be called by both methods.

Fixes: 3e7bed52719d ("macintosh: therm_windtunnel: drop using attach_adapter")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201723
Reported-by: Erhard Furtner <erhard_f@mailbox.org>
Tested-by: Erhard Furtner <erhard_f@mailbox.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org # v4.19+
drivers/macintosh/therm_windtunnel.c