The implementation of ssm2518_register_volatile always returns false,
this behavior is the same as no .volatile_reg callback implementation
when cache_type != REGCACHE_NONE.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
        .num_dapm_routes = ARRAY_SIZE(ssm2518_routes),
 };
 
-static bool ssm2518_register_volatile(struct device *dev, unsigned int reg)
-{
-       return false;
-}
-
 static const struct regmap_config ssm2518_regmap_config = {
        .val_bits = 8,
        .reg_bits = 8,
 
        .max_register = SSM2518_REG_DRC_9,
-       .volatile_reg = ssm2518_register_volatile,
 
        .cache_type = REGCACHE_RBTREE,
        .reg_defaults = ssm2518_reg_defaults,