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 874d5105f83c998bef6c36e88a6d172df2924954..b47dad15fa3ec844479f3dae38521f2a6a9247fd 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 95ccab3f454a9511a27acc7cf351eac52a5dbdb5..7daa78a2f34223948b4a6c47c3f2e10f15ca01ad 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 */