Add bcm2708_gpio driver

Signed-off-by: popcornmix <[email protected]>

bcm2708: Add extension to configure internal pulls

The bcm2708 gpio controller supports internal pulls to be used as pull-up,
pull-down or being entirely disabled. As it can be useful for a driver to
change the pull configuration from it's default pull-down state, add an
extension which allows configuring the pull per gpio.

Signed-off-by: Julian Scheel <[email protected]>

bcm2708-gpio: Revert the use of pinctrl_request_gpio

In non-DT systems, pinctrl_request_gpio always fails causing
"requests probe deferral" messages. In DT systems, it isn't useful
because the reference counting is independent of the normal pinctrl
pin reservations.

gpio: Only clear the currently occurring interrupt. Avoids losing interrupts

See: linux #760

bcm2708_gpio: Avoid calling irq_unmask for all interrupts

When setting up the interrupts, specify that the handle_simple_irq
handler should be used. This leaves interrupt acknowledgement to
the caller, and prevents irq_unmask from being called for all
interrupts.

Issue: linux #760

arch/arm/mach-bcm2708/Kconfig

@@ -20,6 +20,14 @@ config BCM2708_DT
 	help
 	  Enable Device Tree support for BCM2708
 
+config BCM2708_GPIO
+	bool "BCM2708 gpio support"
+	depends on MACH_BCM2708
+	select ARCH_REQUIRE_GPIOLIB
+        default y
+	help
+	  Include support for the Broadcom(R) BCM2708 gpio.
+
 config BCM2708_NOL2CACHE
 	bool "Videocore L2 cache disable"
 	depends on MACH_BCM2708

arch/arm/mach-bcm2708/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_MACH_BCM2708) 	+= bcm2708.o armctrl.o
+obj-$(CONFIG_BCM2708_GPIO)	+= bcm2708_gpio.o

arch/arm/mach-bcm2708/bcm2708.c

@@ -287,6 +287,31 @@ static struct platform_device bcm2708_rpifw_device = {
 	},
 };
 
+#ifdef CONFIG_BCM2708_GPIO
+#define BCM_GPIO_DRIVER_NAME "bcm2708_gpio"
+
+static struct resource bcm2708_gpio_resources[] = {
+	[0] = {			/* general purpose I/O */
+	       .start = GPIO_BASE,
+	       .end = GPIO_BASE + SZ_4K - 1,
+	       .flags = IORESOURCE_MEM,
+	       },
+};
+
+static u64 gpio_dmamask = DMA_BIT_MASK(DMA_MASK_BITS_COMMON);
+
+static struct platform_device bcm2708_gpio_device = {
+	.name = BCM_GPIO_DRIVER_NAME,
+	.id = -1,		/* only one VideoCore I/O area */
+	.resource = bcm2708_gpio_resources,
+	.num_resources = ARRAY_SIZE(bcm2708_gpio_resources),
+	.dev = {
+		.dma_mask = &gpio_dmamask,
+		.coherent_dma_mask = DMA_BIT_MASK(DMA_MASK_BITS_COMMON),
+		},
+};
+#endif
+
 int __init bcm_register_device(struct platform_device *pdev)
 {
 	int ret;