[U-Boot] [PATCH] mmc: fsl_esdhc: fix ddr mode settings

[Peng Fan]

When sd/mmc work at DDR mode, like HS400/HS400ES/DDR52/DDR50
mode, the output clock rate is half of the internal clock rate.
But first need set DDR_EN bit first , then hardware will
automatically divide the usdhc clock.

The mixctrl register exits on new i.MX SoC since i.MX6, so add
CONFIG check.

Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/mmc/fsl_esdhc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 377b2673a3..acd6e08abb 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -625,6 +625,19 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
 	int sdhc_clk = priv->sdhc_clk;
 	uint clk;
 
+	/*
+	 * For ddr mode, usdhc need to enable DDR mode first,
+	 * after select this DDR mode, usdhc will automatically
+	 * divide the usdhc clock
+	 */
+	if (CONFIG_IS_ENABLED(ARCH_MX6) || CONFIG_IS_ENABLED(ARCH_MX7) ||
+	    CONFIG_IS_ENABLED(ARCH_MX7ULP) || CONFIG_IS_ENABLED(ARCH_IMX8) ||
+	    CONFIG_IS_ENABLED(ARCH_IMX8M)) {
+		if (mmc->ddr_mode)
+			writel(readl(&regs->mixctrl) | MIX_CTRL_DDREN,
+			       &regs->mixctrl);
+	}
+
 	if (clock < mmc->cfg->f_min)
 		clock = mmc->cfg->f_min;
 
-- 
2.16.4