diff --git a/drivers/ram/rockchip/sdram_rk3188.c b/drivers/ram/rockchip/sdram_rk3188.c
index 272b1b2..ad9f936 100644
--- a/drivers/ram/rockchip/sdram_rk3188.c
+++ b/drivers/ram/rockchip/sdram_rk3188.c
@@ -867,7 +867,7 @@
 	memcpy(&plat->base, of_plat->rockchip_sdram_params, sizeof(plat->base));
 	/* rk3188 supports dual-channel, set default channel num to 2 */
 	plat->num_channels = 1;
-	ret = regmap_init_mem_plat(dev, of_plat->reg,
+	ret = regmap_init_mem_plat(dev, of_plat->reg, sizeof(of_plat->reg[0]),
 				   ARRAY_SIZE(of_plat->reg) / 2, &plat->map);
 	if (ret)
 		return ret;