mmc: uniphier-sd: just return if already set to desired clock rate

With this, we can save unnecessary udelay().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

diff --git a/drivers/mmc/uniphier-sd.c b/drivers/mmc/uniphier-sd.c
index 40a5c85e373f2df34a60020d19a89ea2d4c7779c..701b26f44cf7f8c02efd8554a30bc6aa726c31bf 100644 (file)
--- a/drivers/mmc/uniphier-sd.c
+++ b/drivers/mmc/uniphier-sd.c
@@ -571,6 +571,9 @@ static void uniphier_sd_set_clk_rate(struct uniphier_sd_priv *priv,
                val = UNIPHIER_SD_CLKCTL_DIV1024;
 
        tmp = readl(priv->regbase + UNIPHIER_SD_CLKCTL);
+       if (tmp & UNIPHIER_SD_CLKCTL_SCLKEN &&
+           (tmp & UNIPHIER_SD_CLKCTL_DIV_MASK) == val)
+               return;
 
        /* stop the clock before changing its rate to avoid a glitch signal */
        tmp &= ~UNIPHIER_SD_CLKCTL_SCLKEN;
@@ -582,6 +585,8 @@ static void uniphier_sd_set_clk_rate(struct uniphier_sd_priv *priv,
 
        tmp |= UNIPHIER_SD_CLKCTL_SCLKEN;
        writel(tmp, priv->regbase + UNIPHIER_SD_CLKCTL);
+
+       udelay(1000);
 }
 
 static int uniphier_sd_set_ios(struct udevice *dev)
@@ -599,8 +604,6 @@ static int uniphier_sd_set_ios(struct udevice *dev)
        uniphier_sd_set_ddr_mode(priv, mmc);
        uniphier_sd_set_clk_rate(priv, mmc);
 
-       udelay(1000);
-
        return 0;
 }