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From:   Wenchao Chen <wenchao.chen@unisoc.com>
To:     <adrian.hunter@intel.com>, <ulf.hansson@linaro.org>,
        <orsonzhai@gmail.com>, <baolin.wang@linux.alibaba.com>,
        <zhang.lyra@gmail.com>
CC:     <linux-mmc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <zhenxiong.lai@unisoc.com>, <yuelin.tang@unisoc.com>
Subject: [PATCH] mmc: sdhci-sprd: Disable CLK_AUTO when the clock is less than 400K
Date:   Wed, 7 Dec 2022 13:19:09 +0800
Message-ID: <20221207051909.32126-1-wenchao.chen@unisoc.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

When the clock is less than 400K, some SD cards fail to initialize
because CLK_AUTO is enabled.

Fixes: fb8bd90f83c4 ("mmc: sdhci-sprd: Add Spreadtrum's initial host controller")
Signed-off-by: Wenchao Chen <wenchao.chen@unisoc.com>
---
 drivers/mmc/host/sdhci-sprd.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
index bec3f9e3cd3f..525f979e2a97 100644
--- a/drivers/mmc/host/sdhci-sprd.c
+++ b/drivers/mmc/host/sdhci-sprd.c
@@ -228,13 +228,15 @@ static inline void _sdhci_sprd_set_clock(struct sdhci_host *host,
 	div = ((div & 0x300) >> 2) | ((div & 0xFF) << 8);
 	sdhci_enable_clk(host, div);
 
-	/* enable auto gate sdhc_enable_auto_gate */
-	val = sdhci_readl(host, SDHCI_SPRD_REG_32_BUSY_POSI);
-	mask = SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN |
-	       SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN;
-	if (mask != (val & mask)) {
-		val |= mask;
-		sdhci_writel(host, val, SDHCI_SPRD_REG_32_BUSY_POSI);
+	/* Enable CLK_AUTO when the clock is greater than 400K. */
+	if (clk > 400000) {
+		val = sdhci_readl(host, SDHCI_SPRD_REG_32_BUSY_POSI);
+		mask = SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN |
+			SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN;
+		if (mask != (val & mask)) {
+			val |= mask;
+			sdhci_writel(host, val, SDHCI_SPRD_REG_32_BUSY_POSI);
+		}
 	}
 }
 
-- 
2.17.1