mmc: sdhci-esdhc-imx: add tuning-step setting support

tuning-step is the delay cell steps in tuning procedure. The default value
of tuning-step is 1. Some boards or cards need another value to pass the
tuning procedure. For example, imx7d-sdb board need the tuning-step value
as 2, otherwise it can't pass the tuning procedure.

So this patch add the tuning-step setting in driver, so that user can set
the tuning-step value in dts.

Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
Acked-by: Dong Aisheng <aisheng.dong@freescale.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

2 files changed, 10 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index b8b7e8842ed0..298551d00fa4 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -75,6 +75,7 @@
 #define ESDHC_STD_TUNING_EN             (1 << 24)
 /* NOTE: the minimum valid tuning start tap for mx6sl is 1 */
 #define ESDHC_TUNING_START_TAP          0x1
+#define ESDHC_TUNING_STEP_SHIFT         16
 
 /* pinctrl state */
 #define ESDHC_PINCTRL_STATE_100MHZ      "state_100mhz"
@@ -474,6 +475,7 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
                 } else if (imx_data->socdata->flags & ESDHC_FLAG_STD_TUNING) {
                         u32 v = readl(host->ioaddr + SDHCI_ACMD12_ERR);
                         u32 m = readl(host->ioaddr + ESDHC_MIX_CTRL);
+                        u32 tuning_ctrl;
                         if (val & SDHCI_CTRL_TUNED_CLK) {
                                 v |= ESDHC_MIX_CTRL_SMPCLK_SEL;
                         } else {
@@ -484,6 +486,11 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
                         if (val & SDHCI_CTRL_EXEC_TUNING) {
                                 v |= ESDHC_MIX_CTRL_EXE_TUNE;
                                 m |= ESDHC_MIX_CTRL_FBCLK_SEL;
+                                tuning_ctrl = readl(host->ioaddr + ESDHC_TUNING_CTRL);
+                                tuning_ctrl |= ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP;
+                                if (imx_data->boarddata.tuning_step)
+                                        tuning_ctrl |= imx_data->boarddata.tuning_step << ESDHC_TUNING_STEP_SHIFT;
+                                        writel(tuning_ctrl, host->ioaddr + ESDHC_TUNING_CTRL);
                         } else {
                                 v &= ~ESDHC_MIX_CTRL_EXE_TUNE;
                         }
@@ -963,6 +970,8 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
         if (gpio_is_valid(boarddata->wp_gpio))
                 boarddata->wp_type = ESDHC_WP_GPIO;
 
+        of_property_read_u32(np, "fsl,tuning-step", &boarddata->tuning_step);
+
         if (of_find_property(np, "no-1-8-v", NULL))
                 boarddata->support_vsel = false;
         else
diff --git a/include/linux/platform_data/mmc-esdhc-imx.h b/include/linux/platform_data/mmc-esdhc-imx.h
index e1571efa3f2b..95ccab3f454a 100644
--- a/include/linux/platform_data/mmc-esdhc-imx.h
+++ b/include/linux/platform_data/mmc-esdhc-imx.h
@@ -45,5 +45,6 @@ struct esdhc_platform_data {
         int max_bus_width;
         bool support_vsel;
         unsigned int delay_line;
+        unsigned int tuning_step;       /* The delay cell steps in tuning procedure */
 };
 #endif /* __ASM_ARCH_IMX_ESDHC_H */