ARM: bcm2835: enable GPIO/pinctrl

Enable GPIO and pinctrl in Kconfig.

Add required <mach/gpio.h> for gpiolib.

Instantiate the BCM2835 GPIO module in bcm2835.dtsi.

Add a pinctrl definition to bcm2835-rpi-b.dts that sets up all of the
board's required pinmux configuration. GPIO aren't specified; that's
left to gpio_request().

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/Kconfig

@@ -336,15 +336,18 @@ config ARCH_AT91
 
 config ARCH_BCM2835
 	bool "Broadcom BCM2835 family"
-	select ARCH_WANT_OPTIONAL_GPIOLIB
+	select ARCH_REQUIRE_GPIOLIB
 	select ARM_AMBA
 	select ARM_ERRATA_411920
 	select ARM_TIMER_SP804
 	select CLKDEV_LOOKUP
 	select COMMON_CLK
 	select CPU_V6
 	select GENERIC_CLOCKEVENTS
+	select GENERIC_GPIO
 	select MULTI_IRQ_HANDLER
+	select PINCTRL
+	select PINCTRL_BCM2835
 	select SPARSE_IRQ
 	select USE_OF
 	help

arch/arm/boot/dts/bcm2835-rpi-b.dts

@@ -10,3 +10,18 @@
 		reg = <0 0x10000000>;
 	};
 };
+
+&gpio {
+	pinctrl-names = "default";
+	pinctrl-0 = <&alt0 &alt3>;
+
+	alt0: alt0 {
+		brcm,pins = <0 1 2 3 4 5 6 7 8 9 10 11 14 15 40 45>;
+		brcm,function = <4>; /* alt0 */
+	};
+
+	alt3: alt3 {
+		brcm,pins = <48 49 50 51 52 53>;
+		brcm,function = <7>; /* alt3 */
+	};
+};

arch/arm/boot/dts/bcm2835.dtsi

@@ -40,5 +40,28 @@
 			interrupts = <2 25>;
 			clock-frequency = <3000000>;
 		};
+
+		gpio: gpio {
+			compatible = "brcm,bcm2835-gpio";
+			reg = <0x7e200000 0xb4>;
+			/*
+			 * The GPIO IP block is designed for 3 banks of GPIOs.
+			 * Each bank has a GPIO interrupt for itself.
+			 * There is an overall "any bank" interrupt.
+			 * In order, these are GIC interrupts 17, 18, 19, 20.
+			 * Since the BCM2835 only has 2 banks, the 2nd bank
+			 * interrupt output appears to be mirrored onto the
+			 * 3rd bank's interrupt signal.
+			 * So, a bank0 interrupt shows up on 17, 20, and
+			 * a bank1 interrupt shows up on 18, 19, 20!
+			 */
+			interrupts = <2 17>, <2 18>, <2 19>, <2 20>;
+
+			gpio-controller;
+			#gpio-cells = <2>;
+
+			interrupt-controller;
+			#interrupt-cells = <2>;
+		};
 	};
 };

arch/arm/mach-bcm2835/include/mach/gpio.h

@@ -0,0 +1 @@
+/* empty */