pinctrl: add pinctrl driver for imx6dl

The imx6dl is a derivative of imx6q with very limited difference.  These
two SoCs are so compatible that they can be handled as one platform in
software.  That said, we will not have target SOC_IMX6DL but just
reusing SOC_IMX6Q.   That's why the pinctrl-imx6dl driver is added here
with symbol PINCTRL_IMX6Q controlling the build of it.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/fsl,imx6dl-pinctrl.txt

+* Freescale IMX6 DualLite/Solo IOMUX Controller
+
+Please refer to fsl,imx-pinctrl.txt in this directory for common binding part
+and usage.
+
+Required properties:
+- compatible: "fsl,imx6dl-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 imx6dl datasheet for the valid pad
+  config settings.
+
+CONFIG bits definition:
+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 imx6dl-pinfunc.h in device tree source folder for all available
+imx6dl PIN_FUNC_ID.

drivers/pinctrl/Kconfig

@@ -93,12 +93,12 @@ config PINCTRL_IMX53
 	  Say Y here to enable the imx53 pinctrl driver
 
 config PINCTRL_IMX6Q
-	bool "IMX6Q pinctrl driver"
+	bool "IMX6Q/DL pinctrl driver"
 	depends on OF
 	depends on SOC_IMX6Q
 	select PINCTRL_IMX
 	help
-	  Say Y here to enable the imx6q pinctrl driver
+	  Say Y here to enable the imx6q/dl pinctrl driver
 
 config PINCTRL_LANTIQ
 	bool

drivers/pinctrl/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_PINCTRL_IMX35)	+= pinctrl-imx35.o
 obj-$(CONFIG_PINCTRL_IMX51)	+= pinctrl-imx51.o
 obj-$(CONFIG_PINCTRL_IMX53)	+= pinctrl-imx53.o
 obj-$(CONFIG_PINCTRL_IMX6Q)	+= pinctrl-imx6q.o
+obj-$(CONFIG_PINCTRL_IMX6Q)	+= pinctrl-imx6dl.o
 obj-$(CONFIG_PINCTRL_PXA3xx)	+= pinctrl-pxa3xx.o
 obj-$(CONFIG_PINCTRL_FALCON)	+= pinctrl-falcon.o
 obj-$(CONFIG_PINCTRL_MMP2)	+= pinctrl-mmp2.o