MLK-10237-4 mmc: sdhci-esdhc-imx: add tuning-step setting support

tuning-step is the delay cell steps in tuning procedure. This patch
add the tuning-step setting in driver, so that user can set the
tuning-step value in dts.

e.g.
tuning-step = <2>;

this example set the tuning-step as value 2.

This patch also set the tuning-step of i.MX7D as 2, so that the tuning
procedure can execute successfully.

Signed-off-by: Haibo Chen <haibo.chen@freescale.com>

4 files changed, 15 insertions, 4 deletions

diff --git a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt
index 9046ba06c47a..aa470163902c 100644
--- a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt
+++ b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt
@@ -17,6 +17,8 @@ Optional properties:
   to select a proper data sampling window in case the clock quality is not good
   due to signal path is too long on the board. Please refer to eSDHC/uSDHC
   chapter, DLL (Delay Line) section in RM for details.
+- tuning-step : The delay cell steps in tuning procedure.
+  Some boards need to set the tuning-step to make sure it can pass tuning procedure.
 
 Examples:
 
@@ -26,6 +28,7 @@ esdhc@70004000 {
 	interrupts = <1>;
 	fsl,cd-controller;
 	fsl,wp-controller;
+	tuning-step = <2>;
 };
 
 esdhc@70008000 {
diff --git a/arch/arm/boot/dts/imx7d-12x12-arm2.dts b/arch/arm/boot/dts/imx7d-12x12-arm2.dts
index 06325ecb342a..6209482c4820 100644
--- a/arch/arm/boot/dts/imx7d-12x12-arm2.dts
+++ b/arch/arm/boot/dts/imx7d-12x12-arm2.dts
@@ -257,6 +257,7 @@
 	wp-gpios = <&gpio5 10 0>;
 	keep-power-in-suspend;
 	enable-sdio-wakeup;
+	tuning-step = <2>;
 	vmmc-supply = <&reg_sd2_vmmc>;
 	status = "okay";
 };
@@ -267,6 +268,7 @@
 	pinctrl-1 = <&pinctrl_usdhc3_1_100mhz>;
 	pinctrl-2 = <&pinctrl_usdhc3_1_200mhz>;
 	bus-width = <8>;
+	tuning-step = <2>;
 	non-removable;
 	keep-power-in-suspend;
 	status = "okay";
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 10d3a1561b1e..7628c0b7be46 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -76,6 +76,7 @@
 #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
 
 #define ESDHC_TUNING_BLOCK_PATTERN_LEN	64
 
@@ -479,6 +480,7 @@ 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 tmp;
 			if (val & SDHCI_CTRL_TUNED_CLK) {
 				v |= ESDHC_MIX_CTRL_SMPCLK_SEL;
 			} else {
@@ -489,10 +491,11 @@ 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;
-				writel(readl(host->ioaddr + ESDHC_TUNING_CTRL) |
-					ESDHC_STD_TUNING_EN |
-					ESDHC_TUNING_START_TAP,
-					host->ioaddr + ESDHC_TUNING_CTRL);
+				tmp = readl(host->ioaddr + ESDHC_TUNING_CTRL);
+				tmp |= ESDHC_STD_TUNING_EN | ESDHC_TUNING_START_TAP;
+				if (imx_data->boarddata.tuning_step)
+					tmp |= imx_data->boarddata.tuning_step << ESDHC_TUNING_STEP_SHIFT;
+				writel(tmp, host->ioaddr + ESDHC_TUNING_CTRL);
 			} else {
 				v &= ~ESDHC_MIX_CTRL_EXE_TUNE;
 			}
@@ -1011,6 +1014,8 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
 
 	of_property_read_u32(np, "max-frequency", &boarddata->f_max);
 
+	of_property_read_u32(np, "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 75f70f6ac137..cedbf8e63e09 100644
--- 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 {
 	unsigned int f_max;
 	bool support_vsel;
 	unsigned int delay_line;
+	unsigned int tuning_step;	/* The delay cell steps in tuning procedure */
 };
 #endif /* __ASM_ARCH_IMX_ESDHC_H */