diff --git a/include/mmc.h b/include/mmc.h
index 46422f4..686ba00 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -457,10 +457,10 @@
 	 *
 	 * @dev:	Device to check
 	 * @state:	target state
-	 * @timeout:	timeout in us
+	 * @timeout_us:	timeout in us
 	 * @return 0 if dat0 is in the target state, -ve on error
 	 */
-	int (*wait_dat0)(struct udevice *dev, int state, int timeout);
+	int (*wait_dat0)(struct udevice *dev, int state, int timeout_us);
 
 #if CONFIG_IS_ENABLED(MMC_HS400_ES_SUPPORT)
 	/* set_enhanced_strobe() - set HS400 enhanced strobe */
@@ -476,14 +476,14 @@
 int dm_mmc_get_cd(struct udevice *dev);
 int dm_mmc_get_wp(struct udevice *dev);
 int dm_mmc_execute_tuning(struct udevice *dev, uint opcode);
-int dm_mmc_wait_dat0(struct udevice *dev, int state, int timeout);
+int dm_mmc_wait_dat0(struct udevice *dev, int state, int timeout_us);
 
 /* Transition functions for compatibility */
 int mmc_set_ios(struct mmc *mmc);
 int mmc_getcd(struct mmc *mmc);
 int mmc_getwp(struct mmc *mmc);
 int mmc_execute_tuning(struct mmc *mmc, uint opcode);
-int mmc_wait_dat0(struct mmc *mmc, int state, int timeout);
+int mmc_wait_dat0(struct mmc *mmc, int state, int timeout_us);
 int mmc_set_enhanced_strobe(struct mmc *mmc);
 
 #else
@@ -602,8 +602,8 @@
 	u8 part_attr;
 	u8 wr_rel_set;
 	u8 part_config;
-	u8 gen_cmd6_time;
-	u8 part_switch_time;
+	u8 gen_cmd6_time;	/* units: 10 ms */
+	u8 part_switch_time;	/* units: 10 ms */
 	uint tran_speed;
 	uint legacy_speed; /* speed for the legacy mode provided by the card */
 	uint read_bl_len;