linux-stable.git/drivers/base/regmap/regcache.c, branch v7.2

regcache: Sort the local copy of an unsorted reg_defaults array

2026-08-06T12:01:39+00:00

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 
Reviewed-by: Charles Keepax 
Tested-by: Charles Keepax 
Link: https://patch.msgid.link/20260805132250.2637-1-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown

regcache: Use a consistent sort for defaults table

2026-08-06T11:59:47+00:00

When we look up registers in the defaults table we use a binary search,
and we have a regcache_sort_defaults() API to help drivers that constuct
their defaults tables on the fly.  Unfortunately the lookup and the sort
don't use the same comparison function, and to make matters worse the
comparison function used during lookups is written for signed register
numbers rather than the unsigned ones we actually have so can produce
suprising results when some of the addresses have the top bit set.

Standardise on the more explicitly coded function to ensure consistent
results.

Reviewed-by: Peter Ujfalusi 
Reviewed-by: Charles Keepax 
Tested-by: Charles Keepax 
Link: https://patch.msgid.link/20260805-regmap-regcache-sort-v1-1-162186aad8b9@kernel.org
Signed-off-by: Mark Brown

regcache: Do not overwrite error code when finalizing cache after error

2026-06-16T13:13:48+00:00

During regcache initialization, if an error occurs in the
cache_ops->populate callback, and if cache operations include an exit
callback, the error code from populate() is overwritten with the return
value from exit(). This hides the error condition from the caller of
regcache_init(), and can cause NULL pointer dereferences when the regcache
is later accessed.

Fixes: 94a3a95f0315 ("regcache: Add ->populate() callback to separate from ->init()")
Signed-off-by: Francesco Lavra 
Link: https://patch.msgid.link/20260616114429.1852456-1-flavra@baylibre.com
Signed-off-by: Mark Brown

regcache: Move HW readback after cache initialisation

2026-03-05T15:23:01+00:00

Make sure that cache is initialised before calling any IO
using regmap, this makes sure that we won't access NULL or
invalid pointers in the cache which hasn't been initialised.

As a side effect it also makes the ordering of cleaning up
the resources in regcache_exit() to be the same (and correct)
as in the error path of regcache_init(). This is not a problem
right now as they do not have dependencies, but it makes code
robust against potential changes in the future.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260305085449.3184020-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Allocate and free reg_defaults on the same level

2026-03-05T15:23:00+00:00

Currently reg_defaults buffer may be allocated on two different
levels when the user provided them and we duplicate it in regcache_init()
or when user wants us to read back from HW in regcache_hw_init().
This inconsistency makes code harder to follow and maintain. Allocate
and free reg_defaults on the same level in regcache_init() to improve
the readability and maintenance efforts.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260305085449.3184020-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Move count check and cache_bypass assignment to the caller

2026-03-05T15:22:59+00:00

Make regcache_count_cacheable_registers() just a counting routine
without any side effects by moving count check and cache_bypass
assignment to the caller.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260305085449.3184020-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Factor out regcache_hw_exit() helper

2026-03-03T13:03:59+00:00

Factor out regcache_hw_exit() helper to make error and exit paths
clearer. This helps to avoid missing changes in case the code gets
shuffled in the future.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260303092820.2818138-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Amend printf() specifiers when printing registers

2026-03-02T14:51:05+00:00

In one case the 0x is provided in the formatting string, while
the rest use # for that.

In a couple of more cases a decimal signed value specifier is used.

Amend them to use %#x when register is printed. Note, for the case,
when it's related to the read/write, use %x to be in align with
the similar messages in regmap core.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260302095847.2310066-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Define iterator inside for-loop and align their types

2026-03-02T14:51:04+00:00

Some of the iterators may be defined inside the respective for-loop
reducing the scope and potential risk of their misuse. While at it,
align their types based on the type of the upper or lower limits.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260302095847.2310066-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown

regcache: Split regcache_count_cacheable_registers() helper

2026-02-22T23:54:25+00:00

The introduced helper allows to check for the non-cacheable configurations
earlier during initialisation.

Signed-off-by: Andy Shevchenko 
Link: https://patch.msgid.link/20260210161058.53093-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown