Message-Id: <1301665638-29841-1-git-send-email-jamie@jamieiles.com>
Date:	Fri,  1 Apr 2011 14:47:18 +0100
From:	Jamie Iles <jamie@...ieiles.com>
To:	linux-kernel@...r.kernel.org
Cc:	Jamie Iles <jamie@...ieiles.com>,
	Grant Likely <grant.likely@...retlab.ca>
Subject: [PATCH] gpio: support for Synopsys DesignWare APB GPIO

This patch adds support for the Synopsys DesignWare APB GPIO controller
that can be found in some ARM systems.  The controller supports up to
4x32 bit ports and port A is capable of raising interrupts.

Cc: Grant Likely <grant.likely@...retlab.ca>
Signed-off-by: Jamie Iles <jamie@...ieiles.com>
---
 drivers/gpio/Kconfig                  |    8 +
 drivers/gpio/Makefile                 |    1 +
 drivers/gpio/dw_gpio.c                |  573 +++++++++++++++++++++++++++++++++
 include/linux/platform_data/dw_gpio.h |   24 ++
 4 files changed, 606 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/dw_gpio.c
 create mode 100644 include/linux/platform_data/dw_gpio.h

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d3b2953..135d996 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -131,6 +131,14 @@ config GPIO_VX855
 	  additional drivers must be enabled in order to use the
 	  functionality of the device.
 
+config GPIO_DW
+	bool "Synopsys DesignWare APB GPIO controller"
+	depends on GPIOLIB
+	help
+	  Say M here to build support for the Synopsys DesignWare APB
+	  GPIO controller found in some ARM systems.  This GPIO controller
+	  supports upto 4 ports of GPIO and GPIO interrupts on port A.
+
 comment "I2C GPIO expanders:"
 
 config GPIO_MAX7300
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index becef59..377d8b9 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -43,3 +43,4 @@ obj-$(CONFIG_GPIO_SX150X)	+= sx150x.o
 obj-$(CONFIG_GPIO_VX855)	+= vx855_gpio.o
 obj-$(CONFIG_GPIO_ML_IOH)	+= ml_ioh_gpio.o
 obj-$(CONFIG_AB8500_GPIO)       += ab8500-gpio.o
+obj-$(CONFIG_GPIO_DW)		+= dw_gpio.o
diff --git a/drivers/gpio/dw_gpio.c b/drivers/gpio/dw_gpio.c
new file mode 100644
index 0000000..1a474df
--- /dev/null
+++ b/drivers/gpio/dw_gpio.c
@@ -0,0 +1,573 @@
+/*
+ * Driver for the Synopsys DesignWare GPIO Controller.
+ *
+ * Copyright (C) 2011 Picochip Ltd, Jamie Iles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/dw_gpio.h>
+
+struct dw_gpio_chip {
+	struct gpio_chip	chip;
+	void __iomem		*iobase;
+	int			porta_end;
+	int			portb_end;
+	int			portc_end;
+	int			portd_end;
+	int			irq_base;
+	int			nr_irq;
+	spinlock_t		lock;
+};
+
+static inline struct dw_gpio_chip *to_dw_gpio_chip(struct gpio_chip *chip)
+{
+	return container_of(chip, struct dw_gpio_chip, chip);
+}
+
+#define GPIO_SW_PORT_A_DR_REG_OFFSET		0x00
+#define GPIO_SW_PORT_A_DDR_REG_OFFSET		0x04
+#define GPIO_SW_PORT_A_CTL_REG_OFFSET		0x08
+#define GPIO_SW_PORT_B_DR_REG_OFFSET		0x0C
+#define GPIO_SW_PORT_B_DDR_REG_OFFSET		0x10
+#define GPIO_SW_PORT_B_CTL_REG_OFFSET		0x14
+#define GPIO_SW_PORT_C_DR_REG_OFFSET		0x18
+#define GPIO_SW_PORT_C_DDR_REG_OFFSET		0x1C
+#define GPIO_SW_PORT_C_CTL_REG_OFFSET		0x20
+#define GPIO_SW_PORT_D_DR_REG_OFFSET		0x24
+#define GPIO_SW_PORT_D_DDR_REG_OFFSET		0x28
+#define GPIO_SW_PORT_D_CTL_REG_OFFSET		0x2C
+
+#define GPIO_INT_EN_REG_OFFSET			0x30
+#define GPIO_INT_MASK_REG_OFFSET		0x34
+#define GPIO_INT_TYPE_LEVEL_REG_OFFSET		0x38
+#define GPIO_INT_POLARITY_REG_OFFSET		0x3c
+#define GPIO_INT_STATUS_REG_OFFSET		0x40
+#define GPIO_PORT_A_EOI_REG_OFFSET		0x4c
+
+#define GPIO_SW_PORT_A_EXT_REG_OFFSET		0x50
+#define GPIO_SW_PORT_B_EXT_REG_OFFSET		0x54
+#define GPIO_SW_PORT_C_EXT_REG_OFFSET		0x58
+#define GPIO_SW_PORT_D_EXT_REG_OFFSET		0x5C
+
+#define GPIO_CFG1_REG_OFFSET		0x74
+#define GPIO_NR_PORTS_SHIFT		2
+#define GPIO_NR_PORTS_MASK		(0x3 << GPIO_NR_PORTS_SHIFT)
+
+#define GPIO_CFG2_REG_OFFSET		0x70
+#define GPIO_PORTA_WIDTH_SHIFT		0
+#define GPIO_PORTA_WIDTH_MASK		(0x1F << GPIO_PORTA_WIDTH_SHIFT)
+#define GPIO_PORTB_WIDTH_SHIFT		5
+#define GPIO_PORTB_WIDTH_MASK		(0x1F << GPIO_PORTB_WIDTH_SHIFT)
+#define GPIO_PORTC_WIDTH_SHIFT		10
+#define GPIO_PORTC_WIDTH_MASK		(0x1F << GPIO_PORTC_WIDTH_SHIFT)
+#define GPIO_PORTD_WIDTH_SHIFT		15
+#define GPIO_PORTD_WIDTH_MASK		(0x1F << GPIO_PORTD_WIDTH_SHIFT)
+
+/*
+ * Get the port mapping for the controller.  There are 4 possible ports that
+ * we can use but some platforms may reserve ports for hardware purposes that
+ * cannot be used as GPIO so we allow these to be masked off.
+ */
+static void dw_gpio_configure_ports(struct dw_gpio_chip *dw,
+				    unsigned long port_mask)
+{
+	unsigned long cfg1, cfg2;
+	int nr_ports;
+
+	cfg1 = readl(dw->iobase + GPIO_CFG1_REG_OFFSET);
+	cfg2 = readl(dw->iobase + GPIO_CFG2_REG_OFFSET);
+
+	nr_ports = (cfg1 & GPIO_NR_PORTS_MASK) >> GPIO_NR_PORTS_SHIFT;
+
+	if (port_mask & DW_GPIO_PORTA_MASK) {
+		dw->porta_end = ((cfg2 & GPIO_PORTA_WIDTH_MASK) >>
+				 GPIO_PORTA_WIDTH_SHIFT) + 1;
+		if (nr_ports == 1)
+			return;
+	} else
+		dw->porta_end = 0;
+
+	if (port_mask & DW_GPIO_PORTB_MASK) {
+		dw->portb_end = ((cfg2 & GPIO_PORTB_WIDTH_MASK) >>
+				 GPIO_PORTB_WIDTH_SHIFT) + 1 + dw->porta_end;
+		if (nr_ports == 2)
+			return;
+	} else
+		dw->portb_end = dw->porta_end;
+
+	if (port_mask & DW_GPIO_PORTC_MASK) {
+		dw->portc_end = ((cfg2 & GPIO_PORTC_WIDTH_MASK) >>
+				 GPIO_PORTC_WIDTH_SHIFT) + 1 + dw->portb_end;
+		if (nr_ports == 3)
+			return;
+	} else
+		dw->portc_end = dw->portb_end;
+
+	if (port_mask & DW_GPIO_PORTD_MASK)
+		dw->portd_end = ((cfg2 & GPIO_PORTD_WIDTH_MASK) >>
+				 GPIO_PORTD_WIDTH_SHIFT) + 1 + dw->portc_end;
+	else
+		dw->portd_end = dw->portb_end;
+}
+
+#define __DWGPIO_REG(__chip, __gpio_nr, __reg)				\
+	({								\
+		void __iomem *ret = NULL;				\
+		if ((__gpio_nr) <= (__chip)->porta_end)			\
+			ret = ((__chip)->iobase +			\
+				GPIO_SW_PORT_A_##__reg##_REG_OFFSET);	\
+		else if ((__gpio_nr) <= (__chip)->portb_end)		\
+			ret = ((__chip)->iobase +			\
+				GPIO_SW_PORT_B_##__reg##_REG_OFFSET);	\
+		else if ((__gpio_nr) <= (__chip)->portc_end)		\
+			ret = ((__chip)->iobase +			\
+				GPIO_SW_PORT_C_##__reg##_REG_OFFSET);	\
+		else							\
+			ret = ((__chip)->iobase +			\
+				GPIO_SW_PORT_D_##__reg##_REG_OFFSET);	\
+		ret;							\
+	})
+
+#define DWGPIO_DR(__chip, __gpio_nr)	__DWGPIO_REG((__chip), \
+						     (__gpio_nr), DR)
+#define DWGPIO_DDR(__chip, __gpio_nr)	__DWGPIO_REG((__chip), \
+						     (__gpio_nr), DDR)
+#define DWGPIO_CTL(__chip, __gpio_nr)	__DWGPIO_REG((__chip), \
+						     (__gpio_nr), CTL)
+#define DWGPIO_EXT(__chip, __gpio_nr)	__DWGPIO_REG((__chip), \
+						     (__gpio_nr), EXT)
+#define INT_EN_REG(__chip)		((__chip)->iobase + \
+					 GPIO_INT_EN_REG_OFFSET)
+#define INT_MASK_REG(__chip)		((__chip)->iobase + \
+					 GPIO_INT_MASK_REG_OFFSET)
+#define INT_TYPE_REG(__chip)		((__chip)->iobase + \
+					 GPIO_INT_TYPE_LEVEL_REG_OFFSET)
+#define INT_POLARITY_REG(__chip)	((__chip)->iobase + \
+					 GPIO_INT_POLARITY_REG_OFFSET)
+#define INT_STATUS_REG(__chip)		((__chip)->iobase + \
+					 GPIO_INT_STATUS_REG_OFFSET)
+#define EOI_REG(__chip)			((__chip)->iobase + \
+					 GPIO_PORT_A_EOI_REG_OFFSET)
+
+static inline unsigned dw_gpio_bit_offs(struct dw_gpio_chip *dw,
+					unsigned offset)
+{
+	/*
+	 * The gpios are controlled via three sets of registers. The register
+	 * addressing is already taken care of by the __DWGPIO_REG macro,
+	 * this takes care of the bit offsets within each register.
+	 */
+	if (offset <= dw->porta_end)
+		return offset;
+	else if (offset <= dw->portb_end)
+		return offset - dw->porta_end;
+	else if (offset <= dw->portc_end)
+		return offset - dw->portb_end;
+	else
+		return offset - dw->portc_end;
+}
+
+static int dwgpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct dw_gpio_chip *dw = to_dw_gpio_chip(chip);
+	void __iomem *ddr = DWGPIO_DDR(dw, offset);
+	void __iomem *cr = DWGPIO_CTL(dw, offset);
+	unsigned long flags, val, bit_offset = dw_gpio_bit_offs(dw, offset);
+
+	spin_lock_irqsave(&dw->lock, flags);
+	/* Mark the pin as an output. */
+	val = readl(ddr);
+	val &= ~(1 << bit_offset);
+	writel(val, ddr);
+
+	/* Set the pin as software controlled. */
+	val = readl(cr);
+	val &= ~(1 << bit_offset);
+	writel(val, cr);
+	spin_unlock_irqrestore(&dw->lock, flags);
+
+	return 0;
+}
+
+static int dwgpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct dw_gpio_chip *dw = to_dw_gpio_chip(chip);
+	void __iomem *ext = DWGPIO_EXT(dw, offset);
+	unsigned long bit_offset = dw_gpio_bit_offs(dw, offset);
+
+	return !!(readl(ext) & (1 << bit_offset));
+}
+
+static void dwgpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct dw_gpio_chip *dw = to_dw_gpio_chip(chip);
+	void __iomem *dr = DWGPIO_DR(dw, offset);
+	unsigned long val, flags, bit_offset = dw_gpio_bit_offs(dw, offset);
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(dr);
+	val &= ~(1 << bit_offset);
+	val |= (!!value << bit_offset);
+	writel(val, dr);
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static int dwgpio_direction_output(struct gpio_chip *chip, unsigned offset,
+				    int value)
+{
+	struct dw_gpio_chip *dw = to_dw_gpio_chip(chip);
+	void __iomem *ddr = DWGPIO_DDR(dw, offset);
+	void __iomem *cr = DWGPIO_CTL(dw, offset);
+	unsigned long flags, val, bit_offset = dw_gpio_bit_offs(dw, offset);
+
+	/* Set the value first so we don't glitch. */
+	dwgpio_set(chip, offset, value);
+
+	spin_lock_irqsave(&dw->lock, flags);
+	/* Mark the pin as an output. */
+	val = readl(ddr);
+	val |= (1 << bit_offset);
+	writel(val, ddr);
+
+	/* Set the pin as software controlled. */
+	val = readl(cr);
+	val &= ~(1 << bit_offset);
+	writel(val, cr);
+	spin_unlock_irqrestore(&dw->lock, flags);
+
+	return 0;
+}
+
+static int dwgpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct dw_gpio_chip *dw = to_dw_gpio_chip(chip);
+
+	return dw->nr_irq && offset < dw->nr_irq ? dw->irq_base + offset :
+		-EINVAL;
+}
+
+static void dwgpio_irq_enable(struct irq_data *d)
+{
+	int gpio = irq_to_gpio(d->irq);
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	void *port_inten = INT_EN_REG(dw);
+	unsigned long val, flags;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(port_inten);
+	val |= (1 << gpio);
+	writel(val, port_inten);
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static void dwgpio_irq_disable(struct irq_data *d)
+{
+	int gpio = irq_to_gpio(d->irq);
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	void __iomem *port_inten = INT_EN_REG(dw);
+	unsigned long val, flags;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(port_inten);
+	val &= ~(1 << gpio);
+	writel(val, port_inten);
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static void dwgpio_irq_mask(struct irq_data *d)
+{
+	int gpio = irq_to_gpio(d->irq);
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	void __iomem *port_mask = INT_MASK_REG(dw);
+	unsigned long val, flags;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(port_mask);
+	val |= (1 << gpio);
+	writel(val, port_mask);
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static void dwgpio_irq_ack(struct irq_data *d)
+{
+	int gpio = irq_to_gpio(d->irq);
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	void __iomem *port_intmask = INT_MASK_REG(dw);
+	void __iomem *port_eoi = EOI_REG(dw);
+	void __iomem *port_inttype_level = INT_TYPE_REG(dw);
+	unsigned long val, flags;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(port_inttype_level);
+	if (val & (1 << gpio)) {
+		/* Edge-sensitive */
+		val = readl(port_eoi);
+		val |= (1 << gpio);
+		writel(val, port_eoi);
+	} else {
+		/* Level-sensitive */
+		val = readl(port_intmask);
+		val |= (1 << gpio);
+		writel(val, port_intmask);
+	}
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static void dwgpio_irq_unmask(struct irq_data *d)
+{
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	int gpio = irq_to_gpio(d->irq);
+	void __iomem *port_intmask = INT_MASK_REG(dw);
+	unsigned long val, flags;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	val = readl(port_intmask);
+	val &= ~(1 << gpio);
+	writel(val, port_intmask);
+	spin_unlock_irqrestore(&dw->lock, flags);
+}
+
+static int dwgpio_irq_set_type(struct irq_data *d,
+			       unsigned int trigger)
+{
+	int gpio = irq_to_gpio(d->irq);
+	struct dw_gpio_chip *dw = irq_data_get_irq_chip_data(d);
+	void __iomem *port_inttype_level = INT_TYPE_REG(dw);
+	void __iomem *port_int_polarity = INT_POLARITY_REG(dw);
+	unsigned long level, polarity, flags;
+
+	if (trigger & ~(IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING |
+			IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		return -EINVAL;
+
+	spin_lock_irqsave(&dw->lock, flags);
+	level = readl(port_inttype_level);
+	polarity = readl(port_int_polarity);
+
+	if (trigger & IRQ_TYPE_EDGE_RISING) {
+		level	    |= (1 << gpio);
+		polarity    |= (1 << gpio);
+	} else if (trigger & IRQ_TYPE_EDGE_FALLING) {
+		level	    |= (1 << gpio);
+		polarity    &= ~(1 << gpio);
+	} else if (trigger & IRQ_TYPE_LEVEL_HIGH) {
+		level	    &= ~(1 << gpio);
+		polarity    |= (1 << gpio);
+	} else if (trigger & IRQ_TYPE_LEVEL_LOW) {
+		level	    &= ~(1 << gpio);
+		polarity    &= ~(1 << gpio);
+	}
+
+	writel(level, port_inttype_level);
+	writel(polarity, port_int_polarity);
+	spin_unlock_irqrestore(&dw->lock, flags);
+
+	return 0;
+}
+
+static struct irq_chip dwgpio_irqchip = {
+	.name		= "dwgpio",
+	.irq_ack	= dwgpio_irq_ack,
+	.irq_mask	= dwgpio_irq_mask,
+	.irq_unmask	= dwgpio_irq_unmask,
+	.irq_enable	= dwgpio_irq_enable,
+	.irq_disable	= dwgpio_irq_disable,
+	.irq_set_type	= dwgpio_irq_set_type,
+};
+
+static void dw_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct dw_gpio_chip *dw = irq_get_handler_data(irq);
+	int i;
+
+	/*
+	 * Mask and ack the interrupt in the parent interrupt controller
+	 * before handling it.
+	 */
+	desc->irq_data.chip->irq_mask(&desc->irq_data);
+	desc->irq_data.chip->irq_ack(&desc->irq_data);
+	for (;;) {
+		unsigned long status = readl(INT_STATUS_REG(dw));
+
+		if (!status)
+			break;
+		writel(status, EOI_REG(dw));
+
+		for_each_set_bit(i, &status, 8)
+			generic_handle_irq(dw->irq_base + i);
+	}
+	desc->irq_data.chip->irq_unmask(&desc->irq_data);
+}
+
+/*
+ * We want to enable/disable interrupts for the GPIO pins through the GPIO
+ * block itself.  The current configuration assumes a 1-to-1 mapping of GPIO
+ * interrupt sources to IRQ numbers.  We use a chained handler as the GPIO
+ * IRQ's may pass through a separate VIC on some systems so need to be
+ * enabled/disabled there too.
+ *
+ * The chained handler simply converts from the virtual IRQ handler to the
+ * real interrupt source and calls the GPIO IRQ handler.
+ */
+static void dwgpio_irq_init(struct dw_gpio_chip *dw,
+			    struct resource *demux_irqs,
+			    struct resource *irqs)
+{
+	int i;
+
+	if (!demux_irqs && !irqs)
+		return;
+
+	if (!demux_irqs || !irqs ||
+	    resource_size(demux_irqs) != resource_size(irqs)) {
+		dev_warn(dw->chip.dev, "unsupported IRQ demuxing configuration, continuing without GPIO IRQ support\n");
+		return;
+	}
+
+	dw->irq_base = irqs->start;
+
+	writel(0, INT_EN_REG(dw));
+	writel(~0, EOI_REG(dw));
+	for (i = irqs->start; i <= irqs->end; ++i) {
+		irq_set_chip_and_handler_name(i, &dwgpio_irqchip,
+					      handle_simple_irq, "demux");
+		irq_set_chip_data(i, dw);
+		irq_set_status_flags(i, IRQ_TYPE_EDGE_BOTH |
+					IRQ_TYPE_LEVEL_HIGH |
+					IRQ_TYPE_LEVEL_LOW);
+		set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
+	}
+
+	for (i = demux_irqs->start; i <= demux_irqs->end; ++i) {
+		irq_set_handler_data(i, dw);
+		irq_set_chained_handler(i, dw_gpio_irq_handler);
+		set_irq_flags(i, IRQF_VALID);
+	}
+}
+
+static int __devinit dwgpio_probe(struct platform_device *pdev)
+{
+	struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	struct resource *demux_irqs, *irqs;
+	struct dw_gpio_chip *dw = devm_kzalloc(&pdev->dev, sizeof(*dw),
+					       GFP_KERNEL);
+	int err;
+	struct dw_gpio_pdata *pdata = pdev->dev.platform_data;
+
+	if (!dw)
+		return -ENOMEM;
+
+	if (!mem || !pdata)
+		return -ENODEV;
+
+	if (!devm_request_mem_region(&pdev->dev, mem->start, resource_size(mem),
+				     "dwgpio"))
+		return -EBUSY;
+
+	dw->iobase = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
+	if (!dw->iobase)
+		return -ENOMEM;
+
+	dw_gpio_configure_ports(dw, pdata->port_mask);
+
+	dw->chip.direction_input	= dwgpio_direction_input;
+	dw->chip.direction_output	= dwgpio_direction_output;
+	dw->chip.get			= dwgpio_get;
+	dw->chip.set			= dwgpio_set;
+	dw->chip.to_irq			= dwgpio_to_irq;
+	dw->chip.owner			= THIS_MODULE;
+	dw->chip.base			= pdata->gpio_base;
+	dw->chip.ngpio			= pdata->ngpio;
+	dw->chip.dev			= &pdev->dev;
+	spin_lock_init(&dw->lock);
+
+	err = gpiochip_add(&dw->chip);
+	if (err) {
+		dev_err(&pdev->dev, "failed to register dwgpio chip\n");
+		return err;
+	}
+
+	demux_irqs = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irqs = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
+	dwgpio_irq_init(dw, demux_irqs, irqs);
+	platform_set_drvdata(pdev, dw);
+
+	return 0;
+}
+
+static void dwgpio_irq_stop(struct dw_gpio_chip *dw,
+			    struct resource *demux_irqs,
+			    struct resource *irqs)
+{
+	int i;
+
+	if (!demux_irqs || !irqs ||
+	    resource_size(demux_irqs) != resource_size(irqs))
+		return;
+
+	for (i = irqs->start; i < irqs->end; ++i) {
+		irq_set_chip(i, NULL);
+		irq_set_chip_data(i, NULL);
+	}
+
+	for (i = demux_irqs->start; i < demux_irqs->end; ++i) {
+		irq_set_chip(i, NULL);
+		irq_set_chip_data(i, NULL);
+	}
+}
+
+static int __devexit dwgpio_remove(struct platform_device *pdev)
+{
+	struct resource *irqs, *demux_irqs;
+	struct dw_gpio_chip *dw = platform_get_drvdata(pdev);
+	int err;
+
+	demux_irqs = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irqs = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
+	dwgpio_irq_stop(dw, demux_irqs, irqs);
+
+	err = gpiochip_remove(&dw->chip);
+	if (err) {
+		dev_err(&pdev->dev, "failed to remove gpio_chip\n");
+		goto out;
+	}
+
+	platform_set_drvdata(pdev, NULL);
+
+out:
+	return err;
+}
+
+static struct platform_driver dwgpio_driver = {
+	.probe		= dwgpio_probe,
+	.remove		= __devexit_p(dwgpio_remove),
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "dwgpio",
+	},
+};
+
+static int __init dwgpio_init(void)
+{
+	return platform_driver_register(&dwgpio_driver);
+}
+module_init(dwgpio_init);
+
+static void __exit dwgpio_exit(void)
+{
+	platform_driver_unregister(&dwgpio_driver);
+}
+module_exit(dwgpio_exit);
+
+MODULE_AUTHOR("Jamie Iles");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Synopsys DesignWare GPIO driver");
diff --git a/include/linux/platform_data/dw_gpio.h b/include/linux/platform_data/dw_gpio.h
new file mode 100644
index 0000000..1ec64c5
--- /dev/null
+++ b/include/linux/platform_data/dw_gpio.h
@@ -0,0 +1,24 @@
+/*
+ * Platform data for the Synopsys DesignWare GPIO Controller.
+ *
+ * Copyright (C) 2011 Picochip Ltd, Jamie Iles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __DW_GPIO_PDATA_H__
+#define __DW_GPIO_PDATA_H__
+
+#define DW_GPIO_PORTA_MASK	(1 << 0)
+#define DW_GPIO_PORTB_MASK	(1 << 1)
+#define DW_GPIO_PORTC_MASK	(1 << 2)
+#define DW_GPIO_PORTD_MASK	(1 << 3)
+
+struct dw_gpio_pdata {
+	int		gpio_base;	/* First GPIO in the chip. */
+	int		ngpio;		/* Number of GPIO pins. */
+	unsigned long	port_mask;	/* Mask of ports to use for GPIO. */
+};
+
+#endif /* __DW_GPIO_PDATA_H__ */
-- 
1.7.4

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