ARM: sunxi: Add pinctrl driver for Allwinner SoCs

The Allwinner SoCs have an IP module that handle both the muxing and the
GPIOs.

This IP has 8 banks of 32 bits, with a number of pins actually useful
for each of these banks varying from one to another, and depending on
the SoC used on the board.

This driver only implements the pinctrl part, the gpio part will come
eventually.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt

+* Allwinner A1X Pin Controller
+
+The pins controlled by sunXi pin controller are organized in banks,
+each bank has 32 pins.  Each pin has 7 multiplexing functions, with
+the first two functions being GPIO in and out. The configuration on
+the pins includes drive strength and pull-up.
+
+Required properties:
+- compatible: "allwinner,<soc>-pinctrl". Supported SoCs for now are:
+  sun5i-a13.
+- reg: Should contain the register physical address and length for the
+  pin controller.
+
+Please refer to pinctrl-bindings.txt in this directory for details of the
+common pinctrl bindings used by client devices.
+
+A pinctrl node should contain at least one subnodes representing the
+pinctrl groups available on the machine. Each subnode will list the
+pins it needs, and how they should be configured, with regard to muxer
+configuration, drive strength and pullups. If one of these options is
+not set, its actual value will be unspecified.
+
+Required subnode-properties:
+
+- allwinner,pins: List of strings containing the pin name.
+- allwinner,function: Function to mux the pins listed above to.
+
+Optional subnode-properties:
+- allwinner,drive: Integer. Represents the current sent to the pin
+    0: 10 mA
+    1: 20 mA
+    2: 30 mA
+    3: 40 mA
+- allwinner,pull: Integer.
+    0: No resistor
+    1: Pull-up resistor
+    2: Pull-down resistor
+
+Examples:
+
+pinctrl@01c20800 {
+	compatible = "allwinner,sun5i-a13-pinctrl";
+	reg = <0x01c20800 0x400>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	uart1_pins_a: uart1@0 {
+		allwinner,pins = "PE10", "PE11";
+		allwinner,function = "uart1";
+		allwinner,drive = <0>;
+		allwinner,pull = <0>;
+	};
+
+	uart1_pins_b: uart1@1 {
+		allwinner,pins = "PG3", "PG4";
+		allwinner,function = "uart1";
+		allwinner,drive = <0>;
+		allwinner,pull = <0>;
+	};
+};

arch/arm/mach-sunxi/Kconfig

@@ -7,3 +7,4 @@ config ARCH_SUNXI
 	select PINCTRL
 	select SPARSE_IRQ
 	select SUNXI_TIMER
+	select PINCTRL_SUNXI
\ No newline at end of file

drivers/pinctrl/Kconfig

@@ -151,6 +151,11 @@ config PINCTRL_SIRF
 	depends on ARCH_SIRF
 	select PINMUX
 
+config PINCTRL_SUNXI
+	bool
+	select PINMUX
+	select GENERIC_PINCONF
+
 config PINCTRL_TEGRA
 	bool
 	select PINMUX

drivers/pinctrl/Makefile

@@ -30,6 +30,7 @@ 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-$(CONFIG_PINCTRL_SUNXI)	+= pinctrl-sunxi.o
 obj-$(CONFIG_PINCTRL_TEGRA)	+= pinctrl-tegra.o
 obj-$(CONFIG_PINCTRL_TEGRA20)	+= pinctrl-tegra20.o
 obj-$(CONFIG_PINCTRL_TEGRA30)	+= pinctrl-tegra30.o