Merge tag 'regmap-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

Pull regmap updates from Mark Brown:
 "Another small update for regmap, we have one new feature plus a little
  bit of cleanup:

   - Support for sparseness information in the flat cache, allowing
     users that really need the performance properties it provides to
     benefit from the interface and startup time improvements that
     sparsness provides without needing to go all the way to a more
     fancy data structure

   - Cleanup work from Andy Shevchenko, refactoring the cache interface
     in preparation for some future stuff he's working on"

* tag 'regmap-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: sdw-mbq: Reorder regmap_mbq_context struct for better packing
  regmap: i3c: Use ARRAY_SIZE()
  regcache: maple: Split ->populate() from ->init()
  regcache: flat: Split ->populate() from ->init()
  regcache: flat: Remove unneeded check and error message for -ENOMEM
  regcache: rbtree: Split ->populate() from ->init()
  regcache: Add ->populate() callback to separate from ->init()
  regmap: warn users about uninitialized flat cache
  regmap: add flat cache with sparse validity

1 files changed, 11 insertions, 6 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 64cd83b1f7bc..b0b9be750d93 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -55,18 +55,23 @@ struct sdw_slave;
 #define REGMAP_DOWNSHIFT(s)	(s)
 
 /*
- * The supported cache types, the default is no cache.  Any new caches
- * should usually use the maple tree cache unless they specifically
- * require that there are never any allocations at runtime and can't
- * provide defaults in which case they should use the flat cache.  The
- * rbtree cache *may* have some performance advantage for very low end
- * systems that make heavy use of cache syncs but is mainly legacy.
+ * The supported cache types, the default is no cache.  Any new caches should
+ * usually use the maple tree cache unless they specifically require that there
+ * are never any allocations at runtime in which case they should use the sparse
+ * flat cache.  The rbtree cache *may* have some performance advantage for very
+ * low end systems that make heavy use of cache syncs but is mainly legacy.
+ * These caches are sparse and entries will be initialized from hardware if no
+ * default has been provided.
+ * The non-sparse flat cache is provided for compatibility with existing users
+ * and will zero-initialize cache entries for which no defaults are provided.
+ * New users should use the sparse flat cache.
  */
 enum regcache_type {
 	REGCACHE_NONE,
 	REGCACHE_RBTREE,
 	REGCACHE_FLAT,
 	REGCACHE_MAPLE,
+	REGCACHE_FLAT_S,
 };
 
 /**