regmap: Allow users to query the size of register values

Generic infrastructure based on top of regmap may want to operate on
blocks of data and therefore find it useful to find the size of the
register values. Provide an accessor operation for this.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -672,6 +672,21 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(regmap_update_bits_check);
 
+/**
+ * regmap_get_val_bytes(): Report the size of a register value
+ *
+ * Report the size of a register value, mainly intended to for use by
+ * generic infrastructure built on top of regmap.
+ */
+int regmap_get_val_bytes(struct regmap *map)
+{
+	if (map->format.format_write)
+		return -EINVAL;
+
+	return map->format.val_bytes;
+}
+EXPORT_SYMBOL_GPL(regmap_get_val_bytes);
+
 static int __init regmap_initcall(void)
 {
 	regmap_debugfs_initcall();

include/linux/regmap.h

@@ -143,6 +143,7 @@ int regmap_update_bits(struct regmap *map, unsigned int reg,
 int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 			     unsigned int mask, unsigned int val,
 			     bool *change);
+int regmap_get_val_bytes(struct regmap *map);
 
 int regcache_sync(struct regmap *map);
 void regcache_cache_only(struct regmap *map, bool enable);