[PATCH] regcache: Use a consistent sort for defaults table

From: Mark Brown

Date: Wed Aug 05 2026 - 14:04:45 EST


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.

Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/base/regmap/regcache.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index aa8f2efed779..480bc76f9a02 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -727,14 +727,6 @@ unsigned int regcache_get_val(struct regmap *map, const void *base,
return -1;
}

-static int regcache_default_cmp(const void *a, const void *b)
-{
- const struct reg_default *_a = a;
- const struct reg_default *_b = b;
-
- return _a->reg - _b->reg;
-}
-
int regcache_lookup_reg(struct regmap *map, unsigned int reg)
{
struct reg_default key;
@@ -744,7 +736,7 @@ int regcache_lookup_reg(struct regmap *map, unsigned int reg)
key.def = 0;

r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
- sizeof(struct reg_default), regcache_default_cmp);
+ sizeof(struct reg_default), regcache_defaults_cmp);

if (r)
return r - map->reg_defaults;

---
base-commit: 075b74841bd0065a3bda3440873c747938e69b68
change-id: 20260805-regmap-regcache-sort-8d144a68bf8d

Best regards,
--
Mark Brown <broonie@xxxxxxxxxx>