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[U-Boot,4/5] mmc: uniphier-sd: just return if already set to desired clock rate

Message ID 1472104359-23551-5-git-send-email-yamada.masahiro@socionext.com
State Accepted
Commit 4a89a24e26670921614a83098e5c0692de2be86e
Delegated to: Masahiro Yamada
Headers show

Commit Message

Masahiro Yamada Aug. 25, 2016, 5:52 a.m. UTC 
With this, we can save unnecessary udelay().

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

 drivers/mmc/uniphier-sd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/mmc/uniphier-sd.c b/drivers/mmc/uniphier-sd.c
index 40a5c85..701b26f 100644
--- 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;
 }