pinctrl: Add one-register-per-pin type device tree based pinctrl driver

Add one-register-per-pin type device tree based pinctrl driver.

This driver has been tested on omap2+ series of processors,
where there is either an 8 or 16-bit padconf register for each pin.
Support for other similar pinmux controllers can be added.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt

+One-register-per-pin type device tree based pinctrl driver
+
+Required properties:
+- compatible : "pinctrl-single"
+
+- reg : offset and length of the register set for the mux registers
+
+- pinctrl-single,register-width : pinmux register access width in bits
+
+- pinctrl-single,function-mask : mask of allowed pinmux function bits
+  in the pinmux register
+
+Optional properties:
+- pinctrl-single,function-off : function off mode for disabled state if
+  available and same for all registers; if not specified, disabling of
+  pin functions is ignored
+
+This driver assumes that there is only one register for each pin,
+and uses the common pinctrl bindings as specified in the pinctrl-bindings.txt
+document in this directory.
+
+The pin configuration nodes for pinctrl-single are specified as pinctrl
+register offset and value pairs using pinctrl-single,pins. Only the bits
+specified in pinctrl-single,function-mask are updated. For example, setting
+a pin for a device could be done with:
+
+	pinctrl-single,pins = <0xdc 0x118>;
+
+Where 0xdc is the offset from the pinctrl register base address for the
+device pinctrl register, and 0x118 contains the desired value of the
+pinctrl register. See the device example and static board pins example
+below for more information.
+
+Example:
+
+/* SoC common file */
+
+/* first controller instance for pins in core domain */
+pmx_core: pinmux@4a100040 {
+	compatible = "pinctrl-single";
+	reg = <0x4a100040 0x0196>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	pinctrl-single,register-width = <16>;
+	pinctrl-single,function-mask = <0xffff>;
+};
+
+/* second controller instance for pins in wkup domain */
+pmx_wkup: pinmux@4a31e040 {
+	compatible = "pinctrl-single;
+	reg = <0x4a31e040 0x0038>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+	pinctrl-single,register-width = <16>;
+	pinctrl-single,function-mask = <0xffff>;
+};
+
+
+/* board specific .dts file */
+
+&pmx_core {
+
+	/*
+	 * map all board specific static pins enabled by the pinctrl driver
+	 * itself during the boot (or just set them up in the bootloader)
+	 */
+	pinctrl-names = "default";
+	pinctrl-0 = <&board_pins>;
+
+	board_pins: pinmux_board_pins {
+		pinctrl-single,pins = <
+			0x6c 0xf
+			0x6e 0xf
+			0x70 0xf
+			0x72 0xf
+		>;
+	};
+
+	/* map uart2 pins */
+	uart2_pins: pinmux_uart2_pins {
+		pinctrl-single,pins = <
+			0xd8 0x118
+			0xda 0
+			0xdc 0x118
+			0xde 0
+		>;
+	};
+};
+
+&uart2 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&uart2_pins>;
+};

drivers/pinctrl/Kconfig

@@ -102,6 +102,14 @@ config PINCTRL_PXA910
 	select PINCTRL_PXA3xx
 	select PINCONF
 
+config PINCTRL_SINGLE
+	tristate "One-register-per-pin type device tree based pinctrl driver"
+	depends on OF
+	select PINMUX
+	select PINCONF
+	help
+	  This selects the device tree based generic pinctrl driver.
+
 config PINCTRL_SIRF
 	bool "CSR SiRFprimaII pin controller driver"
 	depends on ARCH_PRIMA2

drivers/pinctrl/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_PINCTRL_NOMADIK)	+= pinctrl-nomadik.o
 obj-$(CONFIG_PINCTRL_DB8500)	+= pinctrl-nomadik-db8500.o
 obj-$(CONFIG_PINCTRL_PXA168)	+= pinctrl-pxa168.o
 obj-$(CONFIG_PINCTRL_PXA910)	+= pinctrl-pxa910.o
+obj-$(CONFIG_PINCTRL_SINGLE)	+= pinctrl-single.o
 obj-$(CONFIG_PINCTRL_SIRF)	+= pinctrl-sirf.o
 obj-$(CONFIG_PINCTRL_TEGRA)	+= pinctrl-tegra.o
 obj-$(CONFIG_PINCTRL_TEGRA20)	+= pinctrl-tegra20.o