mmc: dw_mmc: exynos: fix the finding clock sample value

Even though there are candiates value if can't find best value, it's
returned -EIO. It's not proper behavior.
If there is not best value, use a first candiate value to work eMMC.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Cc: stable@vger.kernel.org
Fixes: c537a1c5 ("mmc: dw_mmc: exynos: add variable delay tuning sequence")
Link: https://lore.kernel.org/r/20211022082106.1557-1-jh80.chung@samsung.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc-exynos.c

@@ -464,6 +464,18 @@ static s8 dw_mci_exynos_get_best_clksmpl(u8 candiates)
 		}
 	}
 
+	/*
+	 * If there is no cadiates value, then it needs to return -EIO.
+	 * If there are candiates values and don't find bset clk sample value,
+	 * then use a first candiates clock sample value.
+	 */
+	for (i = 0; i < iter; i++) {
+		__c = ror8(candiates, i);
+		if ((__c & 0x1) == 0x1) {
+			loc = i;
+			goto out;
+		}
+	}
 out:
 	return loc;
 }
@@ -494,6 +506,8 @@ static int dw_mci_exynos_execute_tuning(struct dw_mci_slot *slot, u32 opcode)
 		priv->tuned_sample = found;
 	} else {
 		ret = -EIO;
+		dev_warn(&mmc->class_dev,
+			"There is no candiates value about clksmpl!\n");
 	}
 
 	return ret;