diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c
index 3ec611dc0c09..a905e955bbfc 100644
--- a/drivers/base/regmap/regmap-i2c.c
+++ b/drivers/base/regmap/regmap-i2c.c
@@ -350,7 +350,8 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
 
 		if (quirks->max_write_len &&
 		    (bus->max_raw_write == 0 || bus->max_raw_write > quirks->max_write_len))
-			max_write = quirks->max_write_len;
+			max_write = quirks->max_write_len -
+				(config->reg_bits + config->pad_bits) / BITS_PER_BYTE;
 
 		if (max_read || max_write) {
 			ret_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL);