mmc: host: sdhci-s3c: Add support for pinctrl

This patch adds support for pin configuration using pinctrl subsystem
to the sdhci-s3c driver.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

Documentation/devicetree/bindings/mmc/samsung-sdhci.txt

@@ -12,10 +12,6 @@ is used. The Samsung's SDHCI controller bindings extends this as listed below.
 [A] The property "samsung,cd-pinmux-gpio" can be used as stated in the
     "Optional Board Specific Properties" section below.
 
-[B] If core card-detect bindings and "samsung,cd-pinmux-gpio" property
-    is not specified, it is assumed that there is no card detection
-    mechanism used.
-
 Required SoC Specific Properties:
 - compatible: should be one of the following
   - "samsung,s3c6410-sdhci": For controllers compatible with s3c6410 sdhci
@@ -24,14 +20,18 @@ Required SoC Specific Properties:
     controller.
 
 Required Board Specific Properties:
-- gpios: Should specify the gpios used for clock, command and data lines. The
-  gpio specifier format depends on the gpio controller.
+- Samsung GPIO variant (will be completely replaced by pinctrl):
+  - gpios: Should specify the gpios used for clock, command and data lines. The
+    gpio specifier format depends on the gpio controller.
+- Pinctrl variant (preferred if available):
+  - pinctrl-0: Should specify pin control groups used for this controller.
+  - pinctrl-names: Should contain only one value - "default".
 
 Optional Board Specific Properties:
 - samsung,cd-pinmux-gpio: Specifies the card detect line that is routed
   through a pinmux to the card-detect pin of the card slot. This property
   should be used only if none of the mmc core card-detect properties are
-  used.
+  used. Only for Samsung GPIO variant.
 
 Example:
 	sdhci@12530000 {
@@ -40,12 +40,18 @@ Example:
 		interrupts = <0 75 0>;
 		bus-width = <4>;
 		cd-gpios = <&gpk2 2 2 3 3>;
+
+		/* Samsung GPIO variant */
 		gpios = <&gpk2 0 2 0 3>,  /* clock line */
 			<&gpk2 1 2 0 3>,  /* command line */
 			<&gpk2 3 2 3 3>,  /* data line 0 */
 			<&gpk2 4 2 3 3>,  /* data line 1 */
 			<&gpk2 5 2 3 3>,  /* data line 2 */
 			<&gpk2 6 2 3 3>;  /* data line 3 */
+
+		/* Pinctrl variant */
+		pinctrl-0 = <&sd0_clk &sd0_cmd &sd0_bus4>;
+		pinctrl-names = "default";
 	};
 
 	Note: This example shows both SoC specific and board specific properties

drivers/mmc/host/sdhci-s3c.c

@@ -24,6 +24,7 @@
 #include <linux/of_gpio.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/pinctrl/consumer.h>
 
 #include <linux/mmc/host.h>
 
@@ -57,6 +58,7 @@ struct sdhci_s3c {
 	int			ext_cd_irq;
 	int			ext_cd_gpio;
 	int			*gpios;
+	struct pinctrl          *pctrl;
 
 	struct clk		*clk_io;
 	struct clk		*clk_bus[MAX_BUS_CLK];
@@ -484,8 +486,9 @@ static int __devinit sdhci_s3c_parse_dt(struct device *dev,
 		return -EINVAL;
 	}
 
-	dev_info(dev, "assuming no card detect line available\n");
-	pdata->cd_type = S3C_SDHCI_CD_NONE;
+	/* assuming internal card detect that will be configured by pinctrl */
+	pdata->cd_type = S3C_SDHCI_CD_INTERNAL;
+	goto setup_bus;
 
  found_cd:
 	if (pdata->cd_type == S3C_SDHCI_CD_GPIO) {
@@ -503,6 +506,9 @@ static int __devinit sdhci_s3c_parse_dt(struct device *dev,
 	}
 
  setup_bus:
+	if (!IS_ERR(ourhost->pctrl))
+		return 0;
+
 	/* get the gpios for command, clock and data lines */
 	for (cnt = 0; cnt < NUM_GPIOS(pdata->max_width); cnt++) {
 		gpio = of_get_gpio(node, cnt);
@@ -581,6 +587,8 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
 		goto err_pdata_io_clk;
 	}
 
+	sc->pctrl = devm_pinctrl_get_select_default(&pdev->dev);
+
 	if (pdev->dev.of_node) {
 		ret = sdhci_s3c_parse_dt(&pdev->dev, host, pdata);
 		if (ret)