pinctrl: add pinctrl driver for imx6sl

Add a pinctrl driver for i.MX6 SoloLite based on pinctrl-imx core
driver.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/fsl,imx6sl-pinctrl.txt

+* Freescale IMX6 SoloLite IOMUX Controller
+
+Please refer to fsl,imx-pinctrl.txt in this directory for common binding part
+and usage.
+
+Required properties:
+- compatible: "fsl,imx6sl-iomuxc"
+- fsl,pins: two integers array, represents a group of pins mux and config
+  setting. The format is fsl,pins = <PIN_FUNC_ID CONFIG>, PIN_FUNC_ID is a
+  pin working on a specific function, CONFIG is the pad setting value like
+  pull-up for this pin. Please refer to imx6sl datasheet for the valid pad
+  config settings.
+
+CONFIG bits definition:
+PAD_CTL_LVE                     (1 << 22)
+PAD_CTL_HYS                     (1 << 16)
+PAD_CTL_PUS_100K_DOWN           (0 << 14)
+PAD_CTL_PUS_47K_UP              (1 << 14)
+PAD_CTL_PUS_100K_UP             (2 << 14)
+PAD_CTL_PUS_22K_UP              (3 << 14)
+PAD_CTL_PUE                     (1 << 13)
+PAD_CTL_PKE                     (1 << 12)
+PAD_CTL_ODE                     (1 << 11)
+PAD_CTL_SPEED_LOW               (1 << 6)
+PAD_CTL_SPEED_MED               (2 << 6)
+PAD_CTL_SPEED_HIGH              (3 << 6)
+PAD_CTL_DSE_DISABLE             (0 << 3)
+PAD_CTL_DSE_240ohm              (1 << 3)
+PAD_CTL_DSE_120ohm              (2 << 3)
+PAD_CTL_DSE_80ohm               (3 << 3)
+PAD_CTL_DSE_60ohm               (4 << 3)
+PAD_CTL_DSE_48ohm               (5 << 3)
+PAD_CTL_DSE_40ohm               (6 << 3)
+PAD_CTL_DSE_34ohm               (7 << 3)
+PAD_CTL_SRE_FAST                (1 << 0)
+PAD_CTL_SRE_SLOW                (0 << 0)
+
+Refer to imx6sl-pinfunc.h in device tree source folder for all available
+imx6sl PIN_FUNC_ID.

drivers/pinctrl/Kconfig

@@ -100,6 +100,14 @@ config PINCTRL_IMX6Q
 	help
 	  Say Y here to enable the imx6q/dl pinctrl driver
 
+config PINCTRL_IMX6SL
+	bool "IMX6SL pinctrl driver"
+	depends on OF
+	depends on SOC_IMX6SL
+	select PINCTRL_IMX
+	help
+	  Say Y here to enable the imx6sl pinctrl driver
+
 config PINCTRL_LANTIQ
 	bool
 	depends on LANTIQ