mmc: sdhci-sprd: Disable CLK_AUTO when the clock is less than 400K

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

Fixes: fb8bd90f ("mmc: sdhci-sprd: Add Spreadtrum's initial host controller")
Signed-off-by: Wenchao Chen <wenchao.chen@unisoc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20221207051909.32126-1-wenchao.chen@unisoc.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-sprd.c

@@ -228,7 +228,8 @@ 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 */
+	/* 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;
@@ -236,6 +237,7 @@ static inline void _sdhci_sprd_set_clock(struct sdhci_host *host,
 			val |= mask;
 			sdhci_writel(host, val, SDHCI_SPRD_REG_32_BUSY_POSI);
 		}
+	}
 }
 
 static void sdhci_sprd_enable_phy_dll(struct sdhci_host *host)