regcache: Sort the local copy of an unsorted reg_defaults array

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regcache_lookup_reg() bsearch()es the reg_defaults array, which requires
it to be sorted by ascending register address.  Entries following a
descending step are never found, so regcache_reg_needs_sync() reports
that they need a sync and they are written to the device on every
regcache_sync() even when they were never touched.

Detect the misordering while reg_defaults is validated against the
register stride and sort the local copy.  The check needs no new loop
and sort() only runs for the affected drivers, which are also warned
about.

Note that sort() is not stable, so for arrays with duplicated register
addresses it remains unspecified which entry is found.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20260805132250.2637-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

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Peter Ujfalusi 2026-08-05 16:22:50 +03:00 • committed by Mark Brown

parent 9ed3d974a2

commit 4b05ccb17f

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drivers/base/regmap/regcache.c

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