mmc: renesas_sdhi: clarify handling of selecting TAPs

The comment and the define about how TAPs are selected were confusing to
me because the good TAP was only valid if it was bigger than a *_MAX_*
value. Rename the define and adapt the comment to what really happens.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200408094638.10375-3-wsa+renesas@sang-engineering.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/renesas_sdhi_core.c

@@ -422,7 +422,7 @@ static int renesas_sdhi_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_io
 	return 0;
 }
 
-#define SH_MOBILE_SDHI_MAX_TAP 3
+#define SH_MOBILE_SDHI_MIN_TAP_ROW 3
 
 static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
 {
@@ -446,9 +446,9 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
 	}
 
 	/*
-	 * Find the longest consecutive run of successful probes.  If that
-	 * is more than SH_MOBILE_SDHI_MAX_TAP probes long then use the
-	 * center index as the tap.
+	 * Find the longest consecutive run of successful probes. If that
+	 * is at least SH_MOBILE_SDHI_MIN_TAP_ROW probes long then use the
+	 * center index as the tap, otherwise bail out.
 	 */
 	bitmap_for_each_set_region(priv->taps, rs, re, 0, taps_size) {
 		if (re - rs > tap_cnt) {
@@ -458,7 +458,7 @@ static int renesas_sdhi_select_tuning(struct tmio_mmc_host *host)
 		}
 	}
 
-	if (tap_cnt >= SH_MOBILE_SDHI_MAX_TAP)
+	if (tap_cnt >= SH_MOBILE_SDHI_MIN_TAP_ROW)
 		priv->tap_set = (tap_start + tap_end) / 2 % priv->tap_num;
 	else
 		return -EIO;