mmc: sdhci-esdhc-imx: support setting tuning start point

The delay cells of some SoCs may have less delay per one cell,
for such SoCs, user could set the start delay cell point to bypass
the first a few meaningless tuning commands.

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>

diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 874d510..b47dad1 100644 (file)
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -76,7 +76,8 @@
 #define ESDHC_TUNING_CTRL              0xcc
 #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_START_TAP_DEFAULT 0x1
+#define ESDHC_TUNING_START_TAP_MASK    0xff
 #define ESDHC_TUNING_STEP_MASK         0x00070000
 #define ESDHC_TUNING_STEP_SHIFT                16
 
@@ -490,7 +491,12 @@ static void esdhc_writew_le(struct sdhci_host *host, u16 val, int reg)
                                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;
+                               tuning_ctrl |= ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP_DEFAULT;
+                               if (imx_data->boarddata.tuning_start_tap) {
+                                       tuning_ctrl &= ~ESDHC_TUNING_START_TAP_MASK;
+                                       tuning_ctrl |= imx_data->boarddata.tuning_start_tap;
+                               }
+
                                if (imx_data->boarddata.tuning_step) {
                                        tuning_ctrl &= ~ESDHC_TUNING_STEP_MASK;
                                        tuning_ctrl |= imx_data->boarddata.tuning_step << ESDHC_TUNING_STEP_SHIFT;
@@ -976,6 +982,8 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
                boarddata->wp_type = ESDHC_WP_GPIO;
 
        of_property_read_u32(np, "fsl,tuning-step", &boarddata->tuning_step);
+       of_property_read_u32(np, "fsl,tuning-start-tap",
+                            &boarddata->tuning_start_tap);
 
        if (of_find_property(np, "no-1-8-v", NULL))
                boarddata->support_vsel = false;
@@ -1198,7 +1206,7 @@ static int sdhci_esdhc_imx_probe(struct platform_device *pdev)
 
        if (imx_data->socdata->flags & ESDHC_FLAG_STD_TUNING)
                writel(readl(host->ioaddr + ESDHC_TUNING_CTRL) |
-                       ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP,
+                       ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP_DEFAULT,
                        host->ioaddr + ESDHC_TUNING_CTRL);
 
        if (imx_data->socdata->flags & ESDHC_FLAG_ERR004536)

diff --git a/include/linux/platform_data/mmc-esdhc-imx.h b/include/linux/platform_data/mmc-esdhc-imx.h
index 95ccab3..7daa78a 100644 (file)
--- a/include/linux/platform_data/mmc-esdhc-imx.h
+++ b/include/linux/platform_data/mmc-esdhc-imx.h
@@ -46,5 +46,6 @@ struct esdhc_platform_data {
        bool support_vsel;
        unsigned int delay_line;
        unsigned int tuning_step;       /* The delay cell steps in tuning procedure */
+       unsigned int tuning_start_tap;  /* The start delay cell point in tuning procedure */
 };
 #endif /* __ASM_ARCH_IMX_ESDHC_H */