arch/arm/plat-mxc/gpio.c - maze/linux - Git at Google

 /*
  * MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
  * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
  *
  * Based on code from Freescale,
  * Copyright (C) 2004-2010 Freescale Semiconductor, Inc. All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version 2
  * of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */

 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/gpio.h>
 #include <mach/hardware.h>
 #include <asm-generic/bug.h>

 static struct mxc_gpio_port *mxc_gpio_ports;
 static int gpio_table_size;

 #define cpu_is_mx1_mx2()	(cpu_is_mx1() || cpu_is_mx2())

 #define GPIO_DR		(cpu_is_mx1_mx2() ? 0x1c : 0x00)
 #define GPIO_GDIR	(cpu_is_mx1_mx2() ? 0x00 : 0x04)
 #define GPIO_PSR	(cpu_is_mx1_mx2() ? 0x24 : 0x08)
 #define GPIO_ICR1	(cpu_is_mx1_mx2() ? 0x28 : 0x0C)
 #define GPIO_ICR2	(cpu_is_mx1_mx2() ? 0x2C : 0x10)
 #define GPIO_IMR	(cpu_is_mx1_mx2() ? 0x30 : 0x14)
 #define GPIO_ISR	(cpu_is_mx1_mx2() ? 0x34 : 0x18)

 #define GPIO_INT_LOW_LEV	(cpu_is_mx1_mx2() ? 0x3 : 0x0)
 #define GPIO_INT_HIGH_LEV	(cpu_is_mx1_mx2() ? 0x2 : 0x1)
 #define GPIO_INT_RISE_EDGE	(cpu_is_mx1_mx2() ? 0x0 : 0x2)
 #define GPIO_INT_FALL_EDGE	(cpu_is_mx1_mx2() ? 0x1 : 0x3)
 #define GPIO_INT_NONE		0x4

 /* Note: This driver assumes 32 GPIOs are handled in one register */

 static void _clear_gpio_irqstatus(struct mxc_gpio_port *port, u32 index)
 {
 	__raw_writel(1 << index, port->base + GPIO_ISR);
 }

 static void _set_gpio_irqenable(struct mxc_gpio_port *port, u32 index,
 				int enable)
 {
 	u32 l;

 	l = __raw_readl(port->base + GPIO_IMR);
 	l = (l & (~(1 << index))) | (!!enable << index);
 	__raw_writel(l, port->base + GPIO_IMR);
 }

 static void gpio_ack_irq(struct irq_data *d)
 {
 	u32 gpio = irq_to_gpio(d->irq);
 	_clear_gpio_irqstatus(&mxc_gpio_ports[gpio / 32], gpio & 0x1f);
 }

 static void gpio_mask_irq(struct irq_data *d)
 {
 	u32 gpio = irq_to_gpio(d->irq);
 	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 0);
 }

 static void gpio_unmask_irq(struct irq_data *d)
 {
 	u32 gpio = irq_to_gpio(d->irq);
 	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 1);
 }

 static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset);

 static int gpio_set_irq_type(struct irq_data *d, u32 type)
 {
 	u32 gpio = irq_to_gpio(d->irq);
 	struct mxc_gpio_port *port = &mxc_gpio_ports[gpio / 32];
 	u32 bit, val;
 	int edge;
 	void __iomem *reg = port->base;

 	port->both_edges &= ~(1 << (gpio & 31));
 	switch (type) {
 	case IRQ_TYPE_EDGE_RISING:
 		edge = GPIO_INT_RISE_EDGE;
 		break;
 	case IRQ_TYPE_EDGE_FALLING:
 		edge = GPIO_INT_FALL_EDGE;
 		break;
 	case IRQ_TYPE_EDGE_BOTH:
 		val = mxc_gpio_get(&port->chip, gpio & 31);
 		if (val) {
 			edge = GPIO_INT_LOW_LEV;
 			pr_debug("mxc: set GPIO %d to low trigger\n", gpio);
 		} else {
 			edge = GPIO_INT_HIGH_LEV;
 			pr_debug("mxc: set GPIO %d to high trigger\n", gpio);
 		}
 		port->both_edges |= 1 << (gpio & 31);
 		break;
 	case IRQ_TYPE_LEVEL_LOW:
 		edge = GPIO_INT_LOW_LEV;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
 		edge = GPIO_INT_HIGH_LEV;
 		break;
 	default:
 		return -EINVAL;
 	}

 	reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
 	bit = gpio & 0xf;
 	val = __raw_readl(reg) & ~(0x3 << (bit << 1));
 	__raw_writel(val | (edge << (bit << 1)), reg);
 	_clear_gpio_irqstatus(port, gpio & 0x1f);

 	return 0;
 }

 static void mxc_flip_edge(struct mxc_gpio_port *port, u32 gpio)
 {
 	void __iomem *reg = port->base;
 	u32 bit, val;
 	int edge;

 	reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
 	bit = gpio & 0xf;
 	val = __raw_readl(reg);
 	edge = (val >> (bit << 1)) & 3;
 	val &= ~(0x3 << (bit << 1));
 	if (edge == GPIO_INT_HIGH_LEV) {
 		edge = GPIO_INT_LOW_LEV;
 		pr_debug("mxc: switch GPIO %d to low trigger\n", gpio);
 	} else if (edge == GPIO_INT_LOW_LEV) {
 		edge = GPIO_INT_HIGH_LEV;
 		pr_debug("mxc: switch GPIO %d to high trigger\n", gpio);
 	} else {
 		pr_err("mxc: invalid configuration for GPIO %d: %x\n",
 		       gpio, edge);
 		return;
 	}
 	__raw_writel(val | (edge << (bit << 1)), reg);
 }

 /* handle 32 interrupts in one status register */
 static void mxc_gpio_irq_handler(struct mxc_gpio_port *port, u32 irq_stat)
 {
 	u32 gpio_irq_no_base = port->virtual_irq_start;

 	while (irq_stat != 0) {
 		int irqoffset = fls(irq_stat) - 1;

 		if (port->both_edges & (1 << irqoffset))
 			mxc_flip_edge(port, irqoffset);

 		generic_handle_irq(gpio_irq_no_base + irqoffset);

 		irq_stat &= ~(1 << irqoffset);
 	}
 }

 /* MX1 and MX3 has one interrupt *per* gpio port */
 static void mx3_gpio_irq_handler(u32 irq, struct irq_desc *desc)
 {
 	u32 irq_stat;
 	struct mxc_gpio_port *port = irq_get_handler_data(irq);

 	irq_stat = __raw_readl(port->base + GPIO_ISR) &
 			__raw_readl(port->base + GPIO_IMR);

 	mxc_gpio_irq_handler(port, irq_stat);
 }

 /* MX2 has one interrupt *for all* gpio ports */
 static void mx2_gpio_irq_handler(u32 irq, struct irq_desc *desc)
 {
 	int i;
 	u32 irq_msk, irq_stat;
 	struct mxc_gpio_port *port = irq_get_handler_data(irq);

 	/* walk through all interrupt status registers */
 	for (i = 0; i < gpio_table_size; i++) {
 		irq_msk = __raw_readl(port[i].base + GPIO_IMR);
 		if (!irq_msk)
 			continue;

 		irq_stat = __raw_readl(port[i].base + GPIO_ISR) & irq_msk;
 		if (irq_stat)
 			mxc_gpio_irq_handler(&port[i], irq_stat);
 	}
 }

 /*
  * Set interrupt number "irq" in the GPIO as a wake-up source.
  * While system is running, all registered GPIO interrupts need to have
  * wake-up enabled. When system is suspended, only selected GPIO interrupts
  * need to have wake-up enabled.
  * @param  irq          interrupt source number
  * @param  enable       enable as wake-up if equal to non-zero
  * @return       This function returns 0 on success.
  */
 static int gpio_set_wake_irq(struct irq_data *d, u32 enable)
 {
 	u32 gpio = irq_to_gpio(d->irq);
 	u32 gpio_idx = gpio & 0x1F;
 	struct mxc_gpio_port *port = &mxc_gpio_ports[gpio / 32];

 	if (enable) {
 		if (port->irq_high && (gpio_idx >= 16))
 			enable_irq_wake(port->irq_high);
 		else
 			enable_irq_wake(port->irq);
 	} else {
 		if (port->irq_high && (gpio_idx >= 16))
 			disable_irq_wake(port->irq_high);
 		else
 			disable_irq_wake(port->irq);
 	}

 	return 0;
 }

 static struct irq_chip gpio_irq_chip = {
 	.name = "GPIO",
 	.irq_ack = gpio_ack_irq,
 	.irq_mask = gpio_mask_irq,
 	.irq_unmask = gpio_unmask_irq,
 	.irq_set_type = gpio_set_irq_type,
 	.irq_set_wake = gpio_set_wake_irq,
 };

 static void _set_gpio_direction(struct gpio_chip *chip, unsigned offset,
 				int dir)
 {
 	struct mxc_gpio_port *port =
 		container_of(chip, struct mxc_gpio_port, chip);
 	u32 l;
 	unsigned long flags;

 	spin_lock_irqsave(&port->lock, flags);
 	l = __raw_readl(port->base + GPIO_GDIR);
 	if (dir)
 		l |= 1 << offset;
 	else
 		l &= ~(1 << offset);
 	__raw_writel(l, port->base + GPIO_GDIR);
 	spin_unlock_irqrestore(&port->lock, flags);
 }

 static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct mxc_gpio_port *port =
 		container_of(chip, struct mxc_gpio_port, chip);
 	void __iomem *reg = port->base + GPIO_DR;
 	u32 l;
 	unsigned long flags;

 	spin_lock_irqsave(&port->lock, flags);
 	l = (__raw_readl(reg) & (~(1 << offset))) | (!!value << offset);
 	__raw_writel(l, reg);
 	spin_unlock_irqrestore(&port->lock, flags);
 }

 static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	struct mxc_gpio_port *port =
 		container_of(chip, struct mxc_gpio_port, chip);

 	return (__raw_readl(port->base + GPIO_PSR) >> offset) & 1;
 }

 static int mxc_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 {
 	_set_gpio_direction(chip, offset, 0);
 	return 0;
 }

 static int mxc_gpio_direction_output(struct gpio_chip *chip,
 				     unsigned offset, int value)
 {
 	mxc_gpio_set(chip, offset, value);
 	_set_gpio_direction(chip, offset, 1);
 	return 0;
 }

 int __init mxc_gpio_init(struct mxc_gpio_port *port, int cnt)
 {
 	int i, j;

 	/* save for local usage */
 	mxc_gpio_ports = port;
 	gpio_table_size = cnt;

 	printk(KERN_INFO "MXC GPIO hardware\n");

 	for (i = 0; i < cnt; i++) {
 		/* disable the interrupt and clear the status */
 		__raw_writel(0, port[i].base + GPIO_IMR);
 		__raw_writel(~0, port[i].base + GPIO_ISR);
 		for (j = port[i].virtual_irq_start;
 			j < port[i].virtual_irq_start + 32; j++) {
 			irq_set_chip(j, &gpio_irq_chip);
 			irq_set_handler(j, handle_level_irq);
 			set_irq_flags(j, IRQF_VALID);
 		}

 		/* register gpio chip */
 		port[i].chip.direction_input = mxc_gpio_direction_input;
 		port[i].chip.direction_output = mxc_gpio_direction_output;
 		port[i].chip.get = mxc_gpio_get;
 		port[i].chip.set = mxc_gpio_set;
 		port[i].chip.base = i * 32;
 		port[i].chip.ngpio = 32;

 		spin_lock_init(&port[i].lock);

 		/* its a serious configuration bug when it fails */
 		BUG_ON( gpiochip_add(&port[i].chip) < 0 );

 		if (cpu_is_mx1() || cpu_is_mx3() || cpu_is_mx25() || cpu_is_mx51()) {
 			/* setup one handler for each entry */
 			irq_set_chained_handler(port[i].irq,
 						mx3_gpio_irq_handler);
 			irq_set_handler_data(port[i].irq, &port[i]);
 			if (port[i].irq_high) {
 				/* setup handler for GPIO 16 to 31 */
 				irq_set_chained_handler(port[i].irq_high,
 							mx3_gpio_irq_handler);
 				irq_set_handler_data(port[i].irq_high,
 						     &port[i]);
 			}
 		}
 	}

 	if (cpu_is_mx2()) {
 		/* setup one handler for all GPIO interrupts */
 		irq_set_chained_handler(port[0].irq, mx2_gpio_irq_handler);
 		irq_set_handler_data(port[0].irq, port);
 	}

 	return 0;
 }
	/*
	* MXC GPIO support. (c) 2008 Daniel Mack <daniel@caiaq.de>
	* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
	*
	* Based on code from Freescale,
	* Copyright (C) 2004-2010 Freescale Semiconductor, Inc. All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version 2
	* of the License, or (at your option) any later version.
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	*/

	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/irq.h>
	#include <linux/gpio.h>
	#include <mach/hardware.h>
	#include <asm-generic/bug.h>

	static struct mxc_gpio_port *mxc_gpio_ports;
	static int gpio_table_size;

	#define cpu_is_mx1_mx2() (cpu_is_mx1() \|\| cpu_is_mx2())

	#define GPIO_DR (cpu_is_mx1_mx2() ? 0x1c : 0x00)
	#define GPIO_GDIR (cpu_is_mx1_mx2() ? 0x00 : 0x04)
	#define GPIO_PSR (cpu_is_mx1_mx2() ? 0x24 : 0x08)
	#define GPIO_ICR1 (cpu_is_mx1_mx2() ? 0x28 : 0x0C)
	#define GPIO_ICR2 (cpu_is_mx1_mx2() ? 0x2C : 0x10)
	#define GPIO_IMR (cpu_is_mx1_mx2() ? 0x30 : 0x14)
	#define GPIO_ISR (cpu_is_mx1_mx2() ? 0x34 : 0x18)

	#define GPIO_INT_LOW_LEV (cpu_is_mx1_mx2() ? 0x3 : 0x0)
	#define GPIO_INT_HIGH_LEV (cpu_is_mx1_mx2() ? 0x2 : 0x1)
	#define GPIO_INT_RISE_EDGE (cpu_is_mx1_mx2() ? 0x0 : 0x2)
	#define GPIO_INT_FALL_EDGE (cpu_is_mx1_mx2() ? 0x1 : 0x3)
	#define GPIO_INT_NONE 0x4

	/* Note: This driver assumes 32 GPIOs are handled in one register */

	static void _clear_gpio_irqstatus(struct mxc_gpio_port *port, u32 index)
	{
	__raw_writel(1 << index, port->base + GPIO_ISR);
	}

	static void _set_gpio_irqenable(struct mxc_gpio_port *port, u32 index,
	int enable)
	{
	u32 l;

	l = __raw_readl(port->base + GPIO_IMR);
	l = (l & (~(1 << index))) \| (!!enable << index);
	__raw_writel(l, port->base + GPIO_IMR);
	}

	static void gpio_ack_irq(struct irq_data *d)
	{
	u32 gpio = irq_to_gpio(d->irq);
	_clear_gpio_irqstatus(&mxc_gpio_ports[gpio / 32], gpio & 0x1f);
	}

	static void gpio_mask_irq(struct irq_data *d)
	{
	u32 gpio = irq_to_gpio(d->irq);
	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 0);
	}

	static void gpio_unmask_irq(struct irq_data *d)
	{
	u32 gpio = irq_to_gpio(d->irq);
	_set_gpio_irqenable(&mxc_gpio_ports[gpio / 32], gpio & 0x1f, 1);
	}

	static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset);

	static int gpio_set_irq_type(struct irq_data *d, u32 type)
	{
	u32 gpio = irq_to_gpio(d->irq);
	struct mxc_gpio_port *port = &mxc_gpio_ports[gpio / 32];
	u32 bit, val;
	int edge;
	void __iomem *reg = port->base;

	port->both_edges &= ~(1 << (gpio & 31));
	switch (type) {
	case IRQ_TYPE_EDGE_RISING:
	edge = GPIO_INT_RISE_EDGE;
	break;
	case IRQ_TYPE_EDGE_FALLING:
	edge = GPIO_INT_FALL_EDGE;
	break;
	case IRQ_TYPE_EDGE_BOTH:
	val = mxc_gpio_get(&port->chip, gpio & 31);
	if (val) {
	edge = GPIO_INT_LOW_LEV;
	pr_debug("mxc: set GPIO %d to low trigger\n", gpio);
	} else {
	edge = GPIO_INT_HIGH_LEV;
	pr_debug("mxc: set GPIO %d to high trigger\n", gpio);
	}
	port->both_edges \|= 1 << (gpio & 31);
	break;
	case IRQ_TYPE_LEVEL_LOW:
	edge = GPIO_INT_LOW_LEV;
	break;
	case IRQ_TYPE_LEVEL_HIGH:
	edge = GPIO_INT_HIGH_LEV;
	break;
	default:
	return -EINVAL;
	}

	reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
	bit = gpio & 0xf;
	val = __raw_readl(reg) & ~(0x3 << (bit << 1));
	__raw_writel(val \| (edge << (bit << 1)), reg);
	_clear_gpio_irqstatus(port, gpio & 0x1f);

	return 0;
	}

	static void mxc_flip_edge(struct mxc_gpio_port *port, u32 gpio)
	{
	void __iomem *reg = port->base;
	u32 bit, val;
	int edge;

	reg += GPIO_ICR1 + ((gpio & 0x10) >> 2); /* lower or upper register */
	bit = gpio & 0xf;
	val = __raw_readl(reg);
	edge = (val >> (bit << 1)) & 3;
	val &= ~(0x3 << (bit << 1));
	if (edge == GPIO_INT_HIGH_LEV) {
	edge = GPIO_INT_LOW_LEV;
	pr_debug("mxc: switch GPIO %d to low trigger\n", gpio);
	} else if (edge == GPIO_INT_LOW_LEV) {
	edge = GPIO_INT_HIGH_LEV;
	pr_debug("mxc: switch GPIO %d to high trigger\n", gpio);
	} else {
	pr_err("mxc: invalid configuration for GPIO %d: %x\n",
	gpio, edge);
	return;
	}
	__raw_writel(val \| (edge << (bit << 1)), reg);
	}

	/* handle 32 interrupts in one status register */
	static void mxc_gpio_irq_handler(struct mxc_gpio_port *port, u32 irq_stat)
	{
	u32 gpio_irq_no_base = port->virtual_irq_start;

	while (irq_stat != 0) {
	int irqoffset = fls(irq_stat) - 1;

	if (port->both_edges & (1 << irqoffset))
	mxc_flip_edge(port, irqoffset);

	generic_handle_irq(gpio_irq_no_base + irqoffset);

	irq_stat &= ~(1 << irqoffset);
	}
	}

	/* MX1 and MX3 has one interrupt per gpio port */
	static void mx3_gpio_irq_handler(u32 irq, struct irq_desc *desc)
	{
	u32 irq_stat;
	struct mxc_gpio_port *port = irq_get_handler_data(irq);

	irq_stat = __raw_readl(port->base + GPIO_ISR) &
	__raw_readl(port->base + GPIO_IMR);

	mxc_gpio_irq_handler(port, irq_stat);
	}

	/* MX2 has one interrupt for all gpio ports */
	static void mx2_gpio_irq_handler(u32 irq, struct irq_desc *desc)
	{
	int i;
	u32 irq_msk, irq_stat;
	struct mxc_gpio_port *port = irq_get_handler_data(irq);

	/* walk through all interrupt status registers */
	for (i = 0; i < gpio_table_size; i++) {
	irq_msk = __raw_readl(port[i].base + GPIO_IMR);
	if (!irq_msk)
	continue;

	irq_stat = __raw_readl(port[i].base + GPIO_ISR) & irq_msk;
	if (irq_stat)
	mxc_gpio_irq_handler(&port[i], irq_stat);
	}
	}

	/*
	* Set interrupt number "irq" in the GPIO as a wake-up source.
	* While system is running, all registered GPIO interrupts need to have
	* wake-up enabled. When system is suspended, only selected GPIO interrupts
	* need to have wake-up enabled.
	* @param irq interrupt source number
	* @param enable enable as wake-up if equal to non-zero
	* @return This function returns 0 on success.
	*/
	static int gpio_set_wake_irq(struct irq_data *d, u32 enable)
	{
	u32 gpio = irq_to_gpio(d->irq);
	u32 gpio_idx = gpio & 0x1F;
	struct mxc_gpio_port *port = &mxc_gpio_ports[gpio / 32];

	if (enable) {
	if (port->irq_high && (gpio_idx >= 16))
	enable_irq_wake(port->irq_high);
	else
	enable_irq_wake(port->irq);
	} else {
	if (port->irq_high && (gpio_idx >= 16))
	disable_irq_wake(port->irq_high);
	else
	disable_irq_wake(port->irq);
	}

	return 0;
	}

	static struct irq_chip gpio_irq_chip = {
	.name = "GPIO",
	.irq_ack = gpio_ack_irq,
	.irq_mask = gpio_mask_irq,
	.irq_unmask = gpio_unmask_irq,
	.irq_set_type = gpio_set_irq_type,
	.irq_set_wake = gpio_set_wake_irq,
	};

	static void _set_gpio_direction(struct gpio_chip *chip, unsigned offset,
	int dir)
	{
	struct mxc_gpio_port *port =
	container_of(chip, struct mxc_gpio_port, chip);
	u32 l;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	l = __raw_readl(port->base + GPIO_GDIR);
	if (dir)
	l \|= 1 << offset;
	else
	l &= ~(1 << offset);
	__raw_writel(l, port->base + GPIO_GDIR);
	spin_unlock_irqrestore(&port->lock, flags);
	}

	static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
	{
	struct mxc_gpio_port *port =
	container_of(chip, struct mxc_gpio_port, chip);
	void __iomem *reg = port->base + GPIO_DR;
	u32 l;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);
	l = (__raw_readl(reg) & (~(1 << offset))) \| (!!value << offset);
	__raw_writel(l, reg);
	spin_unlock_irqrestore(&port->lock, flags);
	}

	static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset)
	{
	struct mxc_gpio_port *port =
	container_of(chip, struct mxc_gpio_port, chip);

	return (__raw_readl(port->base + GPIO_PSR) >> offset) & 1;
	}

	static int mxc_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
	{
	_set_gpio_direction(chip, offset, 0);
	return 0;
	}

	static int mxc_gpio_direction_output(struct gpio_chip *chip,
	unsigned offset, int value)
	{
	mxc_gpio_set(chip, offset, value);
	_set_gpio_direction(chip, offset, 1);
	return 0;
	}

	int __init mxc_gpio_init(struct mxc_gpio_port *port, int cnt)
	{
	int i, j;

	/* save for local usage */
	mxc_gpio_ports = port;
	gpio_table_size = cnt;

	printk(KERN_INFO "MXC GPIO hardware\n");

	for (i = 0; i < cnt; i++) {
	/* disable the interrupt and clear the status */
	__raw_writel(0, port[i].base + GPIO_IMR);
	__raw_writel(~0, port[i].base + GPIO_ISR);
	for (j = port[i].virtual_irq_start;
	j < port[i].virtual_irq_start + 32; j++) {
	irq_set_chip(j, &gpio_irq_chip);
	irq_set_handler(j, handle_level_irq);
	set_irq_flags(j, IRQF_VALID);
	}

	/* register gpio chip */
	port[i].chip.direction_input = mxc_gpio_direction_input;
	port[i].chip.direction_output = mxc_gpio_direction_output;
	port[i].chip.get = mxc_gpio_get;
	port[i].chip.set = mxc_gpio_set;
	port[i].chip.base = i * 32;
	port[i].chip.ngpio = 32;

	spin_lock_init(&port[i].lock);

	/* its a serious configuration bug when it fails */
	BUG_ON( gpiochip_add(&port[i].chip) < 0 );

	if (cpu_is_mx1() \|\| cpu_is_mx3() \|\| cpu_is_mx25() \|\| cpu_is_mx51()) {
	/* setup one handler for each entry */
	irq_set_chained_handler(port[i].irq,
	mx3_gpio_irq_handler);
	irq_set_handler_data(port[i].irq, &port[i]);
	if (port[i].irq_high) {
	/* setup handler for GPIO 16 to 31 */
	irq_set_chained_handler(port[i].irq_high,
	mx3_gpio_irq_handler);
	irq_set_handler_data(port[i].irq_high,
	&port[i]);
	}
	}
	}

	if (cpu_is_mx2()) {
	/* setup one handler for all GPIO interrupts */
	irq_set_chained_handler(port[0].irq, mx2_gpio_irq_handler);
	irq_set_handler_data(port[0].irq, port);
	}

	return 0;
	}