regmap: Try cached read before checking if a hardware read is possible

For some register format types we do not provide a parse_val so we can not do a
hardware read. But a cached read is still possible, so try to read from the
cache first, before checking whether a hardware read is possible. Otherwise the
cache becomes pretty useless for these register types.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -434,15 +434,15 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
 {
 	int ret;
 
-	if (!map->format.parse_val)
-		return -EINVAL;
-
 	if (!map->cache_bypass) {
 		ret = regcache_read(map, reg, val);
 		if (ret == 0)
 			return 0;
 	}
 
+	if (!map->format.parse_val)
+		return -EINVAL;
+
 	if (map->cache_only)
 		return -EBUSY;