arch/arm/plat-nomadik/gpio.c - kernel/msm-4.19 - Gitiles

 /*
  * Generic GPIO driver for logic cells found in the Nomadik SoC
  *
  * Copyright (C) 2008,2009 STMicroelectronics
  * Copyright (C) 2009 Alessandro Rubini <rubini@unipv.it>
  *   Rewritten based on work by Prafulla WADASKAR <prafulla.wadaskar@st.com>
  *
  * 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/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/gpio.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>

 #include <mach/hardware.h>
 #include <mach/gpio.h>

 /*
  * The GPIO module in the Nomadik family of Systems-on-Chip is an
  * AMBA device, managing 32 pins and alternate functions.  The logic block
  * is currently only used in the Nomadik.
  *
  * Symbols in this file are called "nmk_gpio" for "nomadik gpio"
  */

 #define NMK_GPIO_PER_CHIP 32
 struct nmk_gpio_chip {
 	struct gpio_chip chip;
 	void __iomem *addr;
 	unsigned int parent_irq;
 	spinlock_t lock;
 	/* Keep track of configured edges */
 	u32 edge_rising;
 	u32 edge_falling;
 };

 /* Mode functions */
 int nmk_gpio_set_mode(int gpio, int gpio_mode)
 {
 	struct nmk_gpio_chip *nmk_chip;
 	unsigned long flags;
 	u32 afunc, bfunc, bit;

 	nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
 	if (!nmk_chip)
 		return -EINVAL;

 	bit = 1 << (gpio - nmk_chip->chip.base);

 	spin_lock_irqsave(&nmk_chip->lock, flags);
 	afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & ~bit;
 	bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & ~bit;
 	if (gpio_mode & NMK_GPIO_ALT_A)
 		afunc |= bit;
 	if (gpio_mode & NMK_GPIO_ALT_B)
 		bfunc |= bit;
 	writel(afunc, nmk_chip->addr + NMK_GPIO_AFSLA);
 	writel(bfunc, nmk_chip->addr + NMK_GPIO_AFSLB);
 	spin_unlock_irqrestore(&nmk_chip->lock, flags);

 	return 0;
 }
 EXPORT_SYMBOL(nmk_gpio_set_mode);

 int nmk_gpio_get_mode(int gpio)
 {
 	struct nmk_gpio_chip *nmk_chip;
 	u32 afunc, bfunc, bit;

 	nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
 	if (!nmk_chip)
 		return -EINVAL;

 	bit = 1 << (gpio - nmk_chip->chip.base);

 	afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & bit;
 	bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & bit;

 	return (afunc ? NMK_GPIO_ALT_A : 0) | (bfunc ? NMK_GPIO_ALT_B : 0);
 }
 EXPORT_SYMBOL(nmk_gpio_get_mode);


 /* IRQ functions */
 static inline int nmk_gpio_get_bitmask(int gpio)
 {
 	return 1 << (gpio % 32);
 }

 static void nmk_gpio_irq_ack(unsigned int irq)
 {
 	int gpio;
 	struct nmk_gpio_chip *nmk_chip;

 	gpio = NOMADIK_IRQ_TO_GPIO(irq);
 	nmk_chip = get_irq_chip_data(irq);
 	if (!nmk_chip)
 		return;
 	writel(nmk_gpio_get_bitmask(gpio), nmk_chip->addr + NMK_GPIO_IC);
 }

 static void nmk_gpio_irq_mask(unsigned int irq)
 {
 	int gpio;
 	struct nmk_gpio_chip *nmk_chip;
 	unsigned long flags;
 	u32 bitmask, reg;

 	gpio = NOMADIK_IRQ_TO_GPIO(irq);
 	nmk_chip = get_irq_chip_data(irq);
 	bitmask = nmk_gpio_get_bitmask(gpio);
 	if (!nmk_chip)
 		return;

 	/* we must individually clear the two edges */
 	spin_lock_irqsave(&nmk_chip->lock, flags);
 	if (nmk_chip->edge_rising & bitmask) {
 		reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
 		reg &= ~bitmask;
 		writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
 	}
 	if (nmk_chip->edge_falling & bitmask) {
 		reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
 		reg &= ~bitmask;
 		writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
 	}
 	spin_unlock_irqrestore(&nmk_chip->lock, flags);
 };

 static void nmk_gpio_irq_unmask(unsigned int irq)
 {
 	int gpio;
 	struct nmk_gpio_chip *nmk_chip;
 	unsigned long flags;
 	u32 bitmask, reg;

 	gpio = NOMADIK_IRQ_TO_GPIO(irq);
 	nmk_chip = get_irq_chip_data(irq);
 	bitmask = nmk_gpio_get_bitmask(gpio);
 	if (!nmk_chip)
 		return;

 	/* we must individually set the two edges */
 	spin_lock_irqsave(&nmk_chip->lock, flags);
 	if (nmk_chip->edge_rising & bitmask) {
 		reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
 		reg |= bitmask;
 		writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
 	}
 	if (nmk_chip->edge_falling & bitmask) {
 		reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
 		reg |= bitmask;
 		writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
 	}
 	spin_unlock_irqrestore(&nmk_chip->lock, flags);
 }

 static int nmk_gpio_irq_set_type(unsigned int irq, unsigned int type)
 {
 	int gpio;
 	struct nmk_gpio_chip *nmk_chip;
 	unsigned long flags;
 	u32 bitmask;

 	gpio = NOMADIK_IRQ_TO_GPIO(irq);
 	nmk_chip = get_irq_chip_data(irq);
 	bitmask = nmk_gpio_get_bitmask(gpio);
 	if (!nmk_chip)
 		return -EINVAL;

 	if (type & IRQ_TYPE_LEVEL_HIGH)
 		return -EINVAL;
 	if (type & IRQ_TYPE_LEVEL_LOW)
 		return -EINVAL;

 	spin_lock_irqsave(&nmk_chip->lock, flags);

 	nmk_chip->edge_rising &= ~bitmask;
 	if (type & IRQ_TYPE_EDGE_RISING)
 		nmk_chip->edge_rising |= bitmask;
 	writel(nmk_chip->edge_rising, nmk_chip->addr + NMK_GPIO_RIMSC);

 	nmk_chip->edge_falling &= ~bitmask;
 	if (type & IRQ_TYPE_EDGE_FALLING)
 		nmk_chip->edge_falling |= bitmask;
 	writel(nmk_chip->edge_falling, nmk_chip->addr + NMK_GPIO_FIMSC);

 	spin_unlock_irqrestore(&nmk_chip->lock, flags);

 	nmk_gpio_irq_unmask(irq);

 	return 0;
 }

 static struct irq_chip nmk_gpio_irq_chip = {
 	.name		= "Nomadik-GPIO",
 	.ack		= nmk_gpio_irq_ack,
 	.mask		= nmk_gpio_irq_mask,
 	.unmask		= nmk_gpio_irq_unmask,
 	.set_type	= nmk_gpio_irq_set_type,
 };

 static void nmk_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 {
 	struct nmk_gpio_chip *nmk_chip;
 	struct irq_chip *host_chip = get_irq_chip(irq);
 	unsigned int gpio_irq;
 	u32 pending;
 	unsigned int first_irq;

 	if (host_chip->mask_ack)
 		host_chip->mask_ack(irq);
 	else {
 		host_chip->mask(irq);
 		if (host_chip->ack)
 			host_chip->ack(irq);
 	}

 	nmk_chip = get_irq_data(irq);
 	first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
 	while ( (pending = readl(nmk_chip->addr + NMK_GPIO_IS)) ) {
 		gpio_irq = first_irq + __ffs(pending);
 		generic_handle_irq(gpio_irq);
 	}

 	host_chip->unmask(irq);
 }

 static int nmk_gpio_init_irq(struct nmk_gpio_chip *nmk_chip)
 {
 	unsigned int first_irq;
 	int i;

 	first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
 	for (i = first_irq; i < first_irq + NMK_GPIO_PER_CHIP; i++) {
 		set_irq_chip(i, &nmk_gpio_irq_chip);
 		set_irq_handler(i, handle_edge_irq);
 		set_irq_flags(i, IRQF_VALID);
 		set_irq_chip_data(i, nmk_chip);
 	}
 	set_irq_chained_handler(nmk_chip->parent_irq, nmk_gpio_irq_handler);
 	set_irq_data(nmk_chip->parent_irq, nmk_chip);
 	return 0;
 }

 /* I/O Functions */
 static int nmk_gpio_make_input(struct gpio_chip *chip, unsigned offset)
 {
 	struct nmk_gpio_chip *nmk_chip =
 		container_of(chip, struct nmk_gpio_chip, chip);

 	writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRC);
 	return 0;
 }

 static int nmk_gpio_make_output(struct gpio_chip *chip, unsigned offset,
 				int val)
 {
 	struct nmk_gpio_chip *nmk_chip =
 		container_of(chip, struct nmk_gpio_chip, chip);

 	writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRS);
 	return 0;
 }

 static int nmk_gpio_get_input(struct gpio_chip *chip, unsigned offset)
 {
 	struct nmk_gpio_chip *nmk_chip =
 		container_of(chip, struct nmk_gpio_chip, chip);
 	u32 bit = 1 << offset;

 	return (readl(nmk_chip->addr + NMK_GPIO_DAT) & bit) != 0;
 }

 static void nmk_gpio_set_output(struct gpio_chip *chip, unsigned offset,
 				int val)
 {
 	struct nmk_gpio_chip *nmk_chip =
 		container_of(chip, struct nmk_gpio_chip, chip);
 	u32 bit = 1 << offset;

 	if (val)
 		writel(bit, nmk_chip->addr + NMK_GPIO_DATS);
 	else
 		writel(bit, nmk_chip->addr + NMK_GPIO_DATC);
 }

 /* This structure is replicated for each GPIO block allocated at probe time */
 static struct gpio_chip nmk_gpio_template = {
 	.direction_input	= nmk_gpio_make_input,
 	.get			= nmk_gpio_get_input,
 	.direction_output	= nmk_gpio_make_output,
 	.set			= nmk_gpio_set_output,
 	.ngpio			= NMK_GPIO_PER_CHIP,
 	.can_sleep		= 0,
 };

 static int __init nmk_gpio_probe(struct platform_device *dev)
 {
 	struct nmk_gpio_platform_data *pdata = dev->dev.platform_data;
 	struct nmk_gpio_chip *nmk_chip;
 	struct gpio_chip *chip;
 	struct resource *res;
 	int irq;
 	int ret;

 	if (!pdata)
 		return -ENODEV;

 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (!res) {
 		ret = -ENOENT;
 		goto out;
 	}

 	irq = platform_get_irq(dev, 0);
 	if (irq < 0) {
 		ret = irq;
 		goto out;
 	}

 	if (request_mem_region(res->start, resource_size(res),
 			       dev_name(&dev->dev)) == NULL) {
 		ret = -EBUSY;
 		goto out;
 	}

 	nmk_chip = kzalloc(sizeof(*nmk_chip), GFP_KERNEL);
 	if (!nmk_chip) {
 		ret = -ENOMEM;
 		goto out_release;
 	}
 	/*
 	 * The virt address in nmk_chip->addr is in the nomadik register space,
 	 * so we can simply convert the resource address, without remapping
 	 */
 	nmk_chip->addr = io_p2v(res->start);
 	nmk_chip->chip = nmk_gpio_template;
 	nmk_chip->parent_irq = irq;
 	spin_lock_init(&nmk_chip->lock);

 	chip = &nmk_chip->chip;
 	chip->base = pdata->first_gpio;
 	chip->label = pdata->name;
 	chip->dev = &dev->dev;
 	chip->owner = THIS_MODULE;

 	ret = gpiochip_add(&nmk_chip->chip);
 	if (ret)
 		goto out_free;

 	platform_set_drvdata(dev, nmk_chip);

 	nmk_gpio_init_irq(nmk_chip);

 	dev_info(&dev->dev, "Bits %i-%i at address %p\n",
 		 nmk_chip->chip.base, nmk_chip->chip.base+31, nmk_chip->addr);
 	return 0;

 out_free:
 	kfree(nmk_chip);
 out_release:
 	release_mem_region(res->start, resource_size(res));
 out:
 	dev_err(&dev->dev, "Failure %i for GPIO %i-%i\n", ret,
 		  pdata->first_gpio, pdata->first_gpio+31);
 	return ret;
 }

 static int __exit nmk_gpio_remove(struct platform_device *dev)
 {
 	struct nmk_gpio_chip *nmk_chip;
 	struct resource *res;

 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);

 	nmk_chip = platform_get_drvdata(dev);
 	gpiochip_remove(&nmk_chip->chip);
 	kfree(nmk_chip);
 	release_mem_region(res->start, resource_size(res));
 	return 0;
 }


 static struct platform_driver nmk_gpio_driver = {
 	.driver = {
 		.owner = THIS_MODULE,
 		.name = "gpio",
 		},
 	.probe = nmk_gpio_probe,
 	.remove = __exit_p(nmk_gpio_remove),
 	.suspend = NULL, /* to be done */
 	.resume = NULL,
 };

 static int __init nmk_gpio_init(void)
 {
 	return platform_driver_register(&nmk_gpio_driver);
 }

 arch_initcall(nmk_gpio_init);

 MODULE_AUTHOR("Prafulla WADASKAR and Alessandro Rubini");
 MODULE_DESCRIPTION("Nomadik GPIO Driver");
 MODULE_LICENSE("GPL");
	/*
	* Generic GPIO driver for logic cells found in the Nomadik SoC
	*
	* Copyright (C) 2008,2009 STMicroelectronics
	* Copyright (C) 2009 Alessandro Rubini <rubini@unipv.it>
	* Rewritten based on work by Prafulla WADASKAR <prafulla.wadaskar@st.com>
	*
	* 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/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/device.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <linux/gpio.h>
	#include <linux/spinlock.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>

	#include <mach/hardware.h>
	#include <mach/gpio.h>

	/*
	* The GPIO module in the Nomadik family of Systems-on-Chip is an
	* AMBA device, managing 32 pins and alternate functions. The logic block
	* is currently only used in the Nomadik.
	*
	* Symbols in this file are called "nmk_gpio" for "nomadik gpio"
	*/

	#define NMK_GPIO_PER_CHIP 32
	struct nmk_gpio_chip {
	struct gpio_chip chip;
	void __iomem *addr;
	unsigned int parent_irq;
	spinlock_t lock;
	/* Keep track of configured edges */
	u32 edge_rising;
	u32 edge_falling;
	};

	/* Mode functions */
	int nmk_gpio_set_mode(int gpio, int gpio_mode)
	{
	struct nmk_gpio_chip *nmk_chip;
	unsigned long flags;
	u32 afunc, bfunc, bit;

	nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
	if (!nmk_chip)
	return -EINVAL;

	bit = 1 << (gpio - nmk_chip->chip.base);

	spin_lock_irqsave(&nmk_chip->lock, flags);
	afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & ~bit;
	bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & ~bit;
	if (gpio_mode & NMK_GPIO_ALT_A)
	afunc \|= bit;
	if (gpio_mode & NMK_GPIO_ALT_B)
	bfunc \|= bit;
	writel(afunc, nmk_chip->addr + NMK_GPIO_AFSLA);
	writel(bfunc, nmk_chip->addr + NMK_GPIO_AFSLB);
	spin_unlock_irqrestore(&nmk_chip->lock, flags);

	return 0;
	}
	EXPORT_SYMBOL(nmk_gpio_set_mode);

	int nmk_gpio_get_mode(int gpio)
	{
	struct nmk_gpio_chip *nmk_chip;
	u32 afunc, bfunc, bit;

	nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
	if (!nmk_chip)
	return -EINVAL;

	bit = 1 << (gpio - nmk_chip->chip.base);

	afunc = readl(nmk_chip->addr + NMK_GPIO_AFSLA) & bit;
	bfunc = readl(nmk_chip->addr + NMK_GPIO_AFSLB) & bit;

	return (afunc ? NMK_GPIO_ALT_A : 0) \| (bfunc ? NMK_GPIO_ALT_B : 0);
	}
	EXPORT_SYMBOL(nmk_gpio_get_mode);


	/* IRQ functions */
	static inline int nmk_gpio_get_bitmask(int gpio)
	{
	return 1 << (gpio % 32);
	}

	static void nmk_gpio_irq_ack(unsigned int irq)
	{
	int gpio;
	struct nmk_gpio_chip *nmk_chip;

	gpio = NOMADIK_IRQ_TO_GPIO(irq);
	nmk_chip = get_irq_chip_data(irq);
	if (!nmk_chip)
	return;
	writel(nmk_gpio_get_bitmask(gpio), nmk_chip->addr + NMK_GPIO_IC);
	}

	static void nmk_gpio_irq_mask(unsigned int irq)
	{
	int gpio;
	struct nmk_gpio_chip *nmk_chip;
	unsigned long flags;
	u32 bitmask, reg;

	gpio = NOMADIK_IRQ_TO_GPIO(irq);
	nmk_chip = get_irq_chip_data(irq);
	bitmask = nmk_gpio_get_bitmask(gpio);
	if (!nmk_chip)
	return;

	/* we must individually clear the two edges */
	spin_lock_irqsave(&nmk_chip->lock, flags);
	if (nmk_chip->edge_rising & bitmask) {
	reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
	reg &= ~bitmask;
	writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
	}
	if (nmk_chip->edge_falling & bitmask) {
	reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
	reg &= ~bitmask;
	writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
	}
	spin_unlock_irqrestore(&nmk_chip->lock, flags);
	};

	static void nmk_gpio_irq_unmask(unsigned int irq)
	{
	int gpio;
	struct nmk_gpio_chip *nmk_chip;
	unsigned long flags;
	u32 bitmask, reg;

	gpio = NOMADIK_IRQ_TO_GPIO(irq);
	nmk_chip = get_irq_chip_data(irq);
	bitmask = nmk_gpio_get_bitmask(gpio);
	if (!nmk_chip)
	return;

	/* we must individually set the two edges */
	spin_lock_irqsave(&nmk_chip->lock, flags);
	if (nmk_chip->edge_rising & bitmask) {
	reg = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
	reg \|= bitmask;
	writel(reg, nmk_chip->addr + NMK_GPIO_RWIMSC);
	}
	if (nmk_chip->edge_falling & bitmask) {
	reg = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
	reg \|= bitmask;
	writel(reg, nmk_chip->addr + NMK_GPIO_FWIMSC);
	}
	spin_unlock_irqrestore(&nmk_chip->lock, flags);
	}

	static int nmk_gpio_irq_set_type(unsigned int irq, unsigned int type)
	{
	int gpio;
	struct nmk_gpio_chip *nmk_chip;
	unsigned long flags;
	u32 bitmask;

	gpio = NOMADIK_IRQ_TO_GPIO(irq);
	nmk_chip = get_irq_chip_data(irq);
	bitmask = nmk_gpio_get_bitmask(gpio);
	if (!nmk_chip)
	return -EINVAL;

	if (type & IRQ_TYPE_LEVEL_HIGH)
	return -EINVAL;
	if (type & IRQ_TYPE_LEVEL_LOW)
	return -EINVAL;

	spin_lock_irqsave(&nmk_chip->lock, flags);

	nmk_chip->edge_rising &= ~bitmask;
	if (type & IRQ_TYPE_EDGE_RISING)
	nmk_chip->edge_rising \|= bitmask;
	writel(nmk_chip->edge_rising, nmk_chip->addr + NMK_GPIO_RIMSC);

	nmk_chip->edge_falling &= ~bitmask;
	if (type & IRQ_TYPE_EDGE_FALLING)
	nmk_chip->edge_falling \|= bitmask;
	writel(nmk_chip->edge_falling, nmk_chip->addr + NMK_GPIO_FIMSC);

	spin_unlock_irqrestore(&nmk_chip->lock, flags);

	nmk_gpio_irq_unmask(irq);

	return 0;
	}

	static struct irq_chip nmk_gpio_irq_chip = {
	.name = "Nomadik-GPIO",
	.ack = nmk_gpio_irq_ack,
	.mask = nmk_gpio_irq_mask,
	.unmask = nmk_gpio_irq_unmask,
	.set_type = nmk_gpio_irq_set_type,
	};

	static void nmk_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
	{
	struct nmk_gpio_chip *nmk_chip;
	struct irq_chip *host_chip = get_irq_chip(irq);
	unsigned int gpio_irq;
	u32 pending;
	unsigned int first_irq;

	if (host_chip->mask_ack)
	host_chip->mask_ack(irq);
	else {
	host_chip->mask(irq);
	if (host_chip->ack)
	host_chip->ack(irq);
	}

	nmk_chip = get_irq_data(irq);
	first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
	while ( (pending = readl(nmk_chip->addr + NMK_GPIO_IS)) ) {
	gpio_irq = first_irq + __ffs(pending);
	generic_handle_irq(gpio_irq);
	}

	host_chip->unmask(irq);
	}

	static int nmk_gpio_init_irq(struct nmk_gpio_chip *nmk_chip)
	{
	unsigned int first_irq;
	int i;

	first_irq = NOMADIK_GPIO_TO_IRQ(nmk_chip->chip.base);
	for (i = first_irq; i < first_irq + NMK_GPIO_PER_CHIP; i++) {
	set_irq_chip(i, &nmk_gpio_irq_chip);
	set_irq_handler(i, handle_edge_irq);
	set_irq_flags(i, IRQF_VALID);
	set_irq_chip_data(i, nmk_chip);
	}
	set_irq_chained_handler(nmk_chip->parent_irq, nmk_gpio_irq_handler);
	set_irq_data(nmk_chip->parent_irq, nmk_chip);
	return 0;
	}

	/* I/O Functions */
	static int nmk_gpio_make_input(struct gpio_chip *chip, unsigned offset)
	{
	struct nmk_gpio_chip *nmk_chip =
	container_of(chip, struct nmk_gpio_chip, chip);

	writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRC);
	return 0;
	}

	static int nmk_gpio_make_output(struct gpio_chip *chip, unsigned offset,
	int val)
	{
	struct nmk_gpio_chip *nmk_chip =
	container_of(chip, struct nmk_gpio_chip, chip);

	writel(1 << offset, nmk_chip->addr + NMK_GPIO_DIRS);
	return 0;
	}

	static int nmk_gpio_get_input(struct gpio_chip *chip, unsigned offset)
	{
	struct nmk_gpio_chip *nmk_chip =
	container_of(chip, struct nmk_gpio_chip, chip);
	u32 bit = 1 << offset;

	return (readl(nmk_chip->addr + NMK_GPIO_DAT) & bit) != 0;
	}

	static void nmk_gpio_set_output(struct gpio_chip *chip, unsigned offset,
	int val)
	{
	struct nmk_gpio_chip *nmk_chip =
	container_of(chip, struct nmk_gpio_chip, chip);
	u32 bit = 1 << offset;

	if (val)
	writel(bit, nmk_chip->addr + NMK_GPIO_DATS);
	else
	writel(bit, nmk_chip->addr + NMK_GPIO_DATC);
	}

	/* This structure is replicated for each GPIO block allocated at probe time */
	static struct gpio_chip nmk_gpio_template = {
	.direction_input = nmk_gpio_make_input,
	.get = nmk_gpio_get_input,
	.direction_output = nmk_gpio_make_output,
	.set = nmk_gpio_set_output,
	.ngpio = NMK_GPIO_PER_CHIP,
	.can_sleep = 0,
	};

	static int __init nmk_gpio_probe(struct platform_device *dev)
	{
	struct nmk_gpio_platform_data *pdata = dev->dev.platform_data;
	struct nmk_gpio_chip *nmk_chip;
	struct gpio_chip *chip;
	struct resource *res;
	int irq;
	int ret;

	if (!pdata)
	return -ENODEV;

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!res) {
	ret = -ENOENT;
	goto out;
	}

	irq = platform_get_irq(dev, 0);
	if (irq < 0) {
	ret = irq;
	goto out;
	}

	if (request_mem_region(res->start, resource_size(res),
	dev_name(&dev->dev)) == NULL) {
	ret = -EBUSY;
	goto out;
	}

	nmk_chip = kzalloc(sizeof(*nmk_chip), GFP_KERNEL);
	if (!nmk_chip) {
	ret = -ENOMEM;
	goto out_release;
	}
	/*
	* The virt address in nmk_chip->addr is in the nomadik register space,
	* so we can simply convert the resource address, without remapping
	*/
	nmk_chip->addr = io_p2v(res->start);
	nmk_chip->chip = nmk_gpio_template;
	nmk_chip->parent_irq = irq;
	spin_lock_init(&nmk_chip->lock);

	chip = &nmk_chip->chip;
	chip->base = pdata->first_gpio;
	chip->label = pdata->name;
	chip->dev = &dev->dev;
	chip->owner = THIS_MODULE;

	ret = gpiochip_add(&nmk_chip->chip);
	if (ret)
	goto out_free;

	platform_set_drvdata(dev, nmk_chip);

	nmk_gpio_init_irq(nmk_chip);

	dev_info(&dev->dev, "Bits %i-%i at address %p\n",
	nmk_chip->chip.base, nmk_chip->chip.base+31, nmk_chip->addr);
	return 0;

	out_free:
	kfree(nmk_chip);
	out_release:
	release_mem_region(res->start, resource_size(res));
	out:
	dev_err(&dev->dev, "Failure %i for GPIO %i-%i\n", ret,
	pdata->first_gpio, pdata->first_gpio+31);
	return ret;
	}

	static int __exit nmk_gpio_remove(struct platform_device *dev)
	{
	struct nmk_gpio_chip *nmk_chip;
	struct resource *res;

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);

	nmk_chip = platform_get_drvdata(dev);
	gpiochip_remove(&nmk_chip->chip);
	kfree(nmk_chip);
	release_mem_region(res->start, resource_size(res));
	return 0;
	}


	static struct platform_driver nmk_gpio_driver = {
	.driver = {
	.owner = THIS_MODULE,
	.name = "gpio",
	},
	.probe = nmk_gpio_probe,
	.remove = __exit_p(nmk_gpio_remove),
	.suspend = NULL, /* to be done */
	.resume = NULL,
	};

	static int __init nmk_gpio_init(void)
	{
	return platform_driver_register(&nmk_gpio_driver);
	}

	arch_initcall(nmk_gpio_init);

	MODULE_AUTHOR("Prafulla WADASKAR and Alessandro Rubini");
	MODULE_DESCRIPTION("Nomadik GPIO Driver");
	MODULE_LICENSE("GPL");