regmap: cache: Provide a get address of value operation

Provide a helper to do the size based index into a block of registers and
use it when reading a value.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/internal.h

@@ -189,6 +189,13 @@ int regcache_write(struct regmap *map,
 			unsigned int reg, unsigned int value);
 int regcache_sync(struct regmap *map);
 
+static inline const void *regcache_get_val_addr(struct regmap *map,
+						const void *base,
+						unsigned int idx)
+{
+	return base + (map->cache_word_size * idx);
+}
+
 unsigned int regcache_get_val(struct regmap *map, const void *base,
 			      unsigned int idx);
 bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,

drivers/base/regmap/regcache.c

@@ -458,8 +458,8 @@ unsigned int regcache_get_val(struct regmap *map, const void *base,
 
 	/* Use device native format if possible */
 	if (map->format.parse_val)
-		return map->format.parse_val(base +
-					     (map->cache_word_size * idx));
+		return map->format.parse_val(regcache_get_val_addr(map, base,
+								   idx));
 
 	switch (map->cache_word_size) {
 	case 1: {