From 697542bceae51f7620af333b065dd09d213629fb Mon Sep 17 00:00:00 2001
From: Jaehoon Chung <jh80.chung@samsung.com>
Date: Fri, 22 Oct 2021 17:21:06 +0900
Subject: [PATCH] mmc: dw_mmc: exynos: fix the finding clock sample value
Git-commit: 697542bceae51f7620af333b065dd09d213629fb
Patch-mainline: v5.15
References: git-fixes stable-5.14.16

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: c537a1c5ff63 ("mmc: dw_mmc: exynos: add variable delay tuning sequence")
Link: https://lore.kernel.org/r/20211022082106.1557-1-jh80.chung@samsung.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mmc/host/dw_mmc-exynos.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index 0c75810812a0..1f8a3c0ddfe1 100644
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/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;
-- 
2.26.2