mmc: mmci: stm32: release the delay block before enabling it

We must locked the delay block on the last frequency set. To avoid being
locked on a previous frequency used, the delay block is firstly disabled.

Change-Id: I430f3afdd3b46668e879e864091284b567193148
Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Amit Mittal <amit.mittal@st.com>

Author: Christophe Kerello

drivers/mmc/host/mmci_stm32_sdmmc.c

@@ -535,10 +535,20 @@ static int sdmmc_dlyb_mp15_prepare(struct mmci_host *host)
 static int sdmmc_dlyb_mp25_enable(struct sdmmc_dlyb *dlyb)
 {
 	u32 cr, sr;
+	int ret;
 
 	cr = readl_relaxed(dlyb->base + SYSCFG_DLYBSD_CR);
-	cr |= DLYBSD_CR_EN;
 
+	cr &= ~DLYBSD_CR_EN;
+	writel_relaxed(cr, dlyb->base + SYSCFG_DLYBSD_CR);
+
+	ret = readl_relaxed_poll_timeout(dlyb->base + SYSCFG_DLYBSD_SR,
+					 sr, !(sr & DLYBSD_SR_LOCK), 1,
+					 DLYBSD_TIMEOUT_1S_IN_US);
+	if (ret)
+		return ret;
+
+	cr |= DLYBSD_CR_EN;
 	writel_relaxed(cr, dlyb->base + SYSCFG_DLYBSD_CR);
 
 	return readl_relaxed_poll_timeout(dlyb->base + SYSCFG_DLYBSD_SR,