mmc: sdhci-esdhc-imx: enable hw auto retuning for STD_TUNING

Enable HW auto retuning when set SDHCI_CTRL_EXEC_TUNING and clear it
when clear SDHCI_CTRL_TUNED_CLK.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -45,6 +45,7 @@
 #define  ESDHC_MIX_CTRL_AC23EN		(1 << 7)
 #define  ESDHC_MIX_CTRL_EXE_TUNE	(1 << 22)
 #define  ESDHC_MIX_CTRL_SMPCLK_SEL	(1 << 23)
+#define  ESDHC_MIX_CTRL_AUTO_TUNE_EN	(1 << 24)
 #define  ESDHC_MIX_CTRL_FBCLK_SEL	(1 << 25)
 #define  ESDHC_MIX_CTRL_HS400_EN	(1 << 26)
 /* Bits 3 and 6 are not SDHCI standard definitions */
@@ -485,11 +486,13 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
 			} else {
 				v &= ~ESDHC_MIX_CTRL_SMPCLK_SEL;
 				m &= ~ESDHC_MIX_CTRL_FBCLK_SEL;
+				m &= ~ESDHC_MIX_CTRL_AUTO_TUNE_EN;
 			}
 
 			if (val & SDHCI_CTRL_EXEC_TUNING) {
 				v |= ESDHC_MIX_CTRL_EXE_TUNE;
 				m |= ESDHC_MIX_CTRL_FBCLK_SEL;
+				m |= ESDHC_MIX_CTRL_AUTO_TUNE_EN;
 				tuning_ctrl = readl(host->ioaddr + ESDHC_TUNING_CTRL);
 				tuning_ctrl |= ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP_DEFAULT;
 				if (imx_data->boarddata.tuning_start_tap) {