arch/arm/mach-tegra/gpio.c - kernel/msm-4.9 - Gitiles

 /*
  * arch/arm/mach-tegra/gpio.c
  *
  * Copyright (c) 2010 Google, Inc
  *
  * Author:
  *	Erik Gilling <konkers@google.com>
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * 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.
  *
  */

 #include <linux/init.h>
 #include <linux/irq.h>

 #include <linux/io.h>
 #include <linux/gpio.h>

 #include <mach/iomap.h>

 #define GPIO_BANK(x)		((x) >> 5)
 #define GPIO_PORT(x)		(((x) >> 3) & 0x3)
 #define GPIO_BIT(x)		((x) & 0x7)

 #define GPIO_REG(x)		(IO_TO_VIRT(TEGRA_GPIO_BASE) +	\
 				 GPIO_BANK(x) * 0x80 +		\
 				 GPIO_PORT(x) * 4)

 #define GPIO_CNF(x)		(GPIO_REG(x) + 0x00)
 #define GPIO_OE(x)		(GPIO_REG(x) + 0x10)
 #define GPIO_OUT(x)		(GPIO_REG(x) + 0X20)
 #define GPIO_IN(x)		(GPIO_REG(x) + 0x30)
 #define GPIO_INT_STA(x)		(GPIO_REG(x) + 0x40)
 #define GPIO_INT_ENB(x)		(GPIO_REG(x) + 0x50)
 #define GPIO_INT_LVL(x)		(GPIO_REG(x) + 0x60)
 #define GPIO_INT_CLR(x)		(GPIO_REG(x) + 0x70)

 #define GPIO_MSK_CNF(x)		(GPIO_REG(x) + 0x800)
 #define GPIO_MSK_OE(x)		(GPIO_REG(x) + 0x810)
 #define GPIO_MSK_OUT(x)		(GPIO_REG(x) + 0X820)
 #define GPIO_MSK_INT_STA(x)	(GPIO_REG(x) + 0x840)
 #define GPIO_MSK_INT_ENB(x)	(GPIO_REG(x) + 0x850)
 #define GPIO_MSK_INT_LVL(x)	(GPIO_REG(x) + 0x860)

 #define GPIO_INT_LVL_MASK		0x010101
 #define GPIO_INT_LVL_EDGE_RISING	0x000101
 #define GPIO_INT_LVL_EDGE_FALLING	0x000100
 #define GPIO_INT_LVL_EDGE_BOTH		0x010100
 #define GPIO_INT_LVL_LEVEL_HIGH		0x000001
 #define GPIO_INT_LVL_LEVEL_LOW		0x000000

 struct tegra_gpio_bank {
 	int bank;
 	int irq;
 	spinlock_t lvl_lock[4];
 };


 static struct tegra_gpio_bank tegra_gpio_banks[] = {
 	{.bank = 0, .irq = INT_GPIO1},
 	{.bank = 1, .irq = INT_GPIO2},
 	{.bank = 2, .irq = INT_GPIO3},
 	{.bank = 3, .irq = INT_GPIO4},
 	{.bank = 4, .irq = INT_GPIO5},
 	{.bank = 5, .irq = INT_GPIO6},
 	{.bank = 6, .irq = INT_GPIO7},
 };

 static int tegra_gpio_compose(int bank, int port, int bit)
 {
 	return (bank << 5) | ((port & 0x3) << 3) | (bit & 0x7);
 }

 static void tegra_gpio_mask_write(u32 reg, int gpio, int value)
 {
 	u32 val;

 	val = 0x100 << GPIO_BIT(gpio);
 	if (value)
 		val |= 1 << GPIO_BIT(gpio);
 	__raw_writel(val, reg);
 }

 void tegra_gpio_enable(int gpio)
 {
 	tegra_gpio_mask_write(GPIO_MSK_CNF(gpio), gpio, 1);
 }

 void tegra_gpio_disable(int gpio)
 {
 	tegra_gpio_mask_write(GPIO_MSK_CNF(gpio), gpio, 0);
 }

 static void tegra_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	tegra_gpio_mask_write(GPIO_MSK_OUT(offset), offset, value);
 }

 static int tegra_gpio_get(struct gpio_chip *chip, unsigned offset)
 {
 	return (__raw_readl(GPIO_IN(offset)) >> GPIO_BIT(offset)) & 0x1;
 }

 static int tegra_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 {
 	tegra_gpio_mask_write(GPIO_MSK_OE(offset), offset, 0);
 	return 0;
 }

 static int tegra_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 					int value)
 {
 	tegra_gpio_set(chip, offset, value);
 	tegra_gpio_mask_write(GPIO_MSK_OE(offset), offset, 1);
 	return 0;
 }


 static struct gpio_chip tegra_gpio_chip = {
 	.label			= "tegra-gpio",
 	.direction_input	= tegra_gpio_direction_input,
 	.get			= tegra_gpio_get,
 	.direction_output	= tegra_gpio_direction_output,
 	.set			= tegra_gpio_set,
 	.base			= 0,
 	.ngpio			= ARCH_NR_GPIOS,
 };

 static void tegra_gpio_irq_ack(unsigned int irq)
 {
 	int gpio = irq - INT_GPIO_BASE;

 	__raw_writel(1 << GPIO_BIT(gpio), GPIO_INT_CLR(gpio));
 }

 static void tegra_gpio_irq_mask(unsigned int irq)
 {
 	int gpio = irq - INT_GPIO_BASE;

 	tegra_gpio_mask_write(GPIO_MSK_INT_ENB(gpio), gpio, 0);
 }

 static void tegra_gpio_irq_unmask(unsigned int irq)
 {
 	int gpio = irq - INT_GPIO_BASE;

 	tegra_gpio_mask_write(GPIO_MSK_INT_ENB(gpio), gpio, 1);
 }

 static int tegra_gpio_irq_set_type(unsigned int irq, unsigned int type)
 {
 	int gpio = irq - INT_GPIO_BASE;
 	struct tegra_gpio_bank *bank = get_irq_chip_data(irq);
 	int port = GPIO_PORT(gpio);
 	int lvl_type;
 	int val;
 	unsigned long flags;

 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_RISING:
 		lvl_type = GPIO_INT_LVL_EDGE_RISING;
 		break;

 	case IRQ_TYPE_EDGE_FALLING:
 		lvl_type = GPIO_INT_LVL_EDGE_FALLING;
 		break;

 	case IRQ_TYPE_EDGE_BOTH:
 		lvl_type = GPIO_INT_LVL_EDGE_BOTH;
 		break;

 	case IRQ_TYPE_LEVEL_HIGH:
 		lvl_type = GPIO_INT_LVL_LEVEL_HIGH;
 		break;

 	case IRQ_TYPE_LEVEL_LOW:
 		lvl_type = GPIO_INT_LVL_LEVEL_LOW;
 		break;

 	default:
 		return -EINVAL;
 	}

 	spin_lock_irqsave(&bank->lvl_lock[port], flags);

 	val = __raw_readl(GPIO_INT_LVL(gpio));
 	val &= ~(GPIO_INT_LVL_MASK << GPIO_BIT(gpio));
 	val |= lvl_type << GPIO_BIT(gpio);
 	__raw_writel(val, GPIO_INT_LVL(gpio));

 	spin_unlock_irqrestore(&bank->lvl_lock[port], flags);

 	if (type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
 		__set_irq_handler_unlocked(irq, handle_level_irq);
 	else if (type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
 		__set_irq_handler_unlocked(irq, handle_edge_irq);

 	return 0;
 }

 static void tegra_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
 {
 	struct tegra_gpio_bank *bank;
 	int port;
 	int pin;
 	int unmasked = 0;

 	desc->chip->ack(irq);

 	bank = get_irq_data(irq);

 	for (port = 0; port < 4; port++) {
 		int gpio = tegra_gpio_compose(bank->bank, port, 0);
 		unsigned long sta = __raw_readl(GPIO_INT_STA(gpio)) &
 			__raw_readl(GPIO_INT_ENB(gpio));
 		u32 lvl = __raw_readl(GPIO_INT_LVL(gpio));

 		for_each_set_bit(pin, &sta, 8) {
 			__raw_writel(1 << pin, GPIO_INT_CLR(gpio));

 			/* if gpio is edge triggered, clear condition
 			 * before executing the hander so that we don't
 			 * miss edges
 			 */
 			if (lvl & (0x100 << pin)) {
 				unmasked = 1;
 				desc->chip->unmask(irq);
 			}

 			generic_handle_irq(gpio_to_irq(gpio + pin));
 		}
 	}

 	if (!unmasked)
 		desc->chip->unmask(irq);

 }


 static struct irq_chip tegra_gpio_irq_chip = {
 	.name		= "GPIO",
 	.ack		= tegra_gpio_irq_ack,
 	.mask		= tegra_gpio_irq_mask,
 	.unmask		= tegra_gpio_irq_unmask,
 	.set_type	= tegra_gpio_irq_set_type,
 };


 /* This lock class tells lockdep that GPIO irqs are in a different
  * category than their parents, so it won't report false recursion.
  */
 static struct lock_class_key gpio_lock_class;

 static int __init tegra_gpio_init(void)
 {
 	struct tegra_gpio_bank *bank;
 	int i;
 	int j;

 	for (i = 0; i < 7; i++) {
 		for (j = 0; j < 4; j++) {
 			int gpio = tegra_gpio_compose(i, j, 0);
 			__raw_writel(0x00, GPIO_INT_ENB(gpio));
 		}
 	}

 	gpiochip_add(&tegra_gpio_chip);

 	for (i = INT_GPIO_BASE; i < (INT_GPIO_BASE + ARCH_NR_GPIOS); i++) {
 		bank = &tegra_gpio_banks[GPIO_BANK(irq_to_gpio(i))];

 		lockdep_set_class(&irq_desc[i].lock, &gpio_lock_class);
 		set_irq_chip_data(i, bank);
 		set_irq_chip(i, &tegra_gpio_irq_chip);
 		set_irq_handler(i, handle_simple_irq);
 		set_irq_flags(i, IRQF_VALID);
 	}

 	for (i = 0; i < ARRAY_SIZE(tegra_gpio_banks); i++) {
 		bank = &tegra_gpio_banks[i];

 		set_irq_chained_handler(bank->irq, tegra_gpio_irq_handler);
 		set_irq_data(bank->irq, bank);

 		for (j = 0; j < 4; j++)
 			spin_lock_init(&bank->lvl_lock[j]);
 	}

 	return 0;
 }

 postcore_initcall(tegra_gpio_init);

 #ifdef	CONFIG_DEBUG_FS

 #include <linux/debugfs.h>
 #include <linux/seq_file.h>

 static int dbg_gpio_show(struct seq_file *s, void *unused)
 {
 	int i;
 	int j;

 	for (i = 0; i < 7; i++) {
 		for (j = 0; j < 4; j++) {
 			int gpio = tegra_gpio_compose(i, j, 0);
 			seq_printf(s, "%d:%d %02x %02x %02x %02x %02x %02x %06x\n",
 			       i, j,
 			       __raw_readl(GPIO_CNF(gpio)),
 			       __raw_readl(GPIO_OE(gpio)),
 			       __raw_readl(GPIO_OUT(gpio)),
 			       __raw_readl(GPIO_IN(gpio)),
 			       __raw_readl(GPIO_INT_STA(gpio)),
 			       __raw_readl(GPIO_INT_ENB(gpio)),
 			       __raw_readl(GPIO_INT_LVL(gpio)));
 		}
 	}
 	return 0;
 }

 static int dbg_gpio_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, dbg_gpio_show, &inode->i_private);
 }

 static const struct file_operations debug_fops = {
 	.open		= dbg_gpio_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };

 static int __init tegra_gpio_debuginit(void)
 {
 	(void) debugfs_create_file("tegra_gpio", S_IRUGO,
 					NULL, NULL, &debug_fops);
 	return 0;
 }
 late_initcall(tegra_gpio_debuginit);
 #endif
	/*
	* arch/arm/mach-tegra/gpio.c
	*
	* Copyright (c) 2010 Google, Inc
	*
	* Author:
	* Erik Gilling <konkers@google.com>
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* 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.
	*
	*/

	#include <linux/init.h>
	#include <linux/irq.h>

	#include <linux/io.h>
	#include <linux/gpio.h>

	#include <mach/iomap.h>

	#define GPIO_BANK(x) ((x) >> 5)
	#define GPIO_PORT(x) (((x) >> 3) & 0x3)
	#define GPIO_BIT(x) ((x) & 0x7)

	#define GPIO_REG(x) (IO_TO_VIRT(TEGRA_GPIO_BASE) + \
	GPIO_BANK(x) * 0x80 + \
	GPIO_PORT(x) * 4)

	#define GPIO_CNF(x) (GPIO_REG(x) + 0x00)
	#define GPIO_OE(x) (GPIO_REG(x) + 0x10)
	#define GPIO_OUT(x) (GPIO_REG(x) + 0X20)
	#define GPIO_IN(x) (GPIO_REG(x) + 0x30)
	#define GPIO_INT_STA(x) (GPIO_REG(x) + 0x40)
	#define GPIO_INT_ENB(x) (GPIO_REG(x) + 0x50)
	#define GPIO_INT_LVL(x) (GPIO_REG(x) + 0x60)
	#define GPIO_INT_CLR(x) (GPIO_REG(x) + 0x70)

	#define GPIO_MSK_CNF(x) (GPIO_REG(x) + 0x800)
	#define GPIO_MSK_OE(x) (GPIO_REG(x) + 0x810)
	#define GPIO_MSK_OUT(x) (GPIO_REG(x) + 0X820)
	#define GPIO_MSK_INT_STA(x) (GPIO_REG(x) + 0x840)
	#define GPIO_MSK_INT_ENB(x) (GPIO_REG(x) + 0x850)
	#define GPIO_MSK_INT_LVL(x) (GPIO_REG(x) + 0x860)

	#define GPIO_INT_LVL_MASK 0x010101
	#define GPIO_INT_LVL_EDGE_RISING 0x000101
	#define GPIO_INT_LVL_EDGE_FALLING 0x000100
	#define GPIO_INT_LVL_EDGE_BOTH 0x010100
	#define GPIO_INT_LVL_LEVEL_HIGH 0x000001
	#define GPIO_INT_LVL_LEVEL_LOW 0x000000

	struct tegra_gpio_bank {
	int bank;
	int irq;
	spinlock_t lvl_lock[4];
	};


	static struct tegra_gpio_bank tegra_gpio_banks[] = {
	{.bank = 0, .irq = INT_GPIO1},
	{.bank = 1, .irq = INT_GPIO2},
	{.bank = 2, .irq = INT_GPIO3},
	{.bank = 3, .irq = INT_GPIO4},
	{.bank = 4, .irq = INT_GPIO5},
	{.bank = 5, .irq = INT_GPIO6},
	{.bank = 6, .irq = INT_GPIO7},
	};

	static int tegra_gpio_compose(int bank, int port, int bit)
	{
	return (bank << 5) \| ((port & 0x3) << 3) \| (bit & 0x7);
	}

	static void tegra_gpio_mask_write(u32 reg, int gpio, int value)
	{
	u32 val;

	val = 0x100 << GPIO_BIT(gpio);
	if (value)
	val \|= 1 << GPIO_BIT(gpio);
	__raw_writel(val, reg);
	}

	void tegra_gpio_enable(int gpio)
	{
	tegra_gpio_mask_write(GPIO_MSK_CNF(gpio), gpio, 1);
	}

	void tegra_gpio_disable(int gpio)
	{
	tegra_gpio_mask_write(GPIO_MSK_CNF(gpio), gpio, 0);
	}

	static void tegra_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
	{
	tegra_gpio_mask_write(GPIO_MSK_OUT(offset), offset, value);
	}

	static int tegra_gpio_get(struct gpio_chip *chip, unsigned offset)
	{
	return (__raw_readl(GPIO_IN(offset)) >> GPIO_BIT(offset)) & 0x1;
	}

	static int tegra_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
	{
	tegra_gpio_mask_write(GPIO_MSK_OE(offset), offset, 0);
	return 0;
	}

	static int tegra_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
	int value)
	{
	tegra_gpio_set(chip, offset, value);
	tegra_gpio_mask_write(GPIO_MSK_OE(offset), offset, 1);
	return 0;
	}



	static struct gpio_chip tegra_gpio_chip = {
	.label = "tegra-gpio",
	.direction_input = tegra_gpio_direction_input,
	.get = tegra_gpio_get,
	.direction_output = tegra_gpio_direction_output,
	.set = tegra_gpio_set,
	.base = 0,
	.ngpio = ARCH_NR_GPIOS,
	};

	static void tegra_gpio_irq_ack(unsigned int irq)
	{
	int gpio = irq - INT_GPIO_BASE;

	__raw_writel(1 << GPIO_BIT(gpio), GPIO_INT_CLR(gpio));
	}

	static void tegra_gpio_irq_mask(unsigned int irq)
	{
	int gpio = irq - INT_GPIO_BASE;

	tegra_gpio_mask_write(GPIO_MSK_INT_ENB(gpio), gpio, 0);
	}

	static void tegra_gpio_irq_unmask(unsigned int irq)
	{
	int gpio = irq - INT_GPIO_BASE;

	tegra_gpio_mask_write(GPIO_MSK_INT_ENB(gpio), gpio, 1);
	}

	static int tegra_gpio_irq_set_type(unsigned int irq, unsigned int type)
	{
	int gpio = irq - INT_GPIO_BASE;
	struct tegra_gpio_bank *bank = get_irq_chip_data(irq);
	int port = GPIO_PORT(gpio);
	int lvl_type;
	int val;
	unsigned long flags;

	switch (type & IRQ_TYPE_SENSE_MASK) {
	case IRQ_TYPE_EDGE_RISING:
	lvl_type = GPIO_INT_LVL_EDGE_RISING;
	break;

	case IRQ_TYPE_EDGE_FALLING:
	lvl_type = GPIO_INT_LVL_EDGE_FALLING;
	break;

	case IRQ_TYPE_EDGE_BOTH:
	lvl_type = GPIO_INT_LVL_EDGE_BOTH;
	break;

	case IRQ_TYPE_LEVEL_HIGH:
	lvl_type = GPIO_INT_LVL_LEVEL_HIGH;
	break;

	case IRQ_TYPE_LEVEL_LOW:
	lvl_type = GPIO_INT_LVL_LEVEL_LOW;
	break;

	default:
	return -EINVAL;
	}

	spin_lock_irqsave(&bank->lvl_lock[port], flags);

	val = __raw_readl(GPIO_INT_LVL(gpio));
	val &= ~(GPIO_INT_LVL_MASK << GPIO_BIT(gpio));
	val \|= lvl_type << GPIO_BIT(gpio);
	__raw_writel(val, GPIO_INT_LVL(gpio));

	spin_unlock_irqrestore(&bank->lvl_lock[port], flags);

	if (type & (IRQ_TYPE_LEVEL_LOW \| IRQ_TYPE_LEVEL_HIGH))
	__set_irq_handler_unlocked(irq, handle_level_irq);
	else if (type & (IRQ_TYPE_EDGE_FALLING \| IRQ_TYPE_EDGE_RISING))
	__set_irq_handler_unlocked(irq, handle_edge_irq);

	return 0;
	}

	static void tegra_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
	{
	struct tegra_gpio_bank *bank;
	int port;
	int pin;
	int unmasked = 0;

	desc->chip->ack(irq);

	bank = get_irq_data(irq);

	for (port = 0; port < 4; port++) {
	int gpio = tegra_gpio_compose(bank->bank, port, 0);
	unsigned long sta = __raw_readl(GPIO_INT_STA(gpio)) &
	__raw_readl(GPIO_INT_ENB(gpio));
	u32 lvl = __raw_readl(GPIO_INT_LVL(gpio));

	for_each_set_bit(pin, &sta, 8) {
	__raw_writel(1 << pin, GPIO_INT_CLR(gpio));

	/* if gpio is edge triggered, clear condition
	* before executing the hander so that we don't
	* miss edges
	*/
	if (lvl & (0x100 << pin)) {
	unmasked = 1;
	desc->chip->unmask(irq);
	}

	generic_handle_irq(gpio_to_irq(gpio + pin));
	}
	}

	if (!unmasked)
	desc->chip->unmask(irq);

	}


	static struct irq_chip tegra_gpio_irq_chip = {
	.name = "GPIO",
	.ack = tegra_gpio_irq_ack,
	.mask = tegra_gpio_irq_mask,
	.unmask = tegra_gpio_irq_unmask,
	.set_type = tegra_gpio_irq_set_type,
	};


	/* This lock class tells lockdep that GPIO irqs are in a different
	* category than their parents, so it won't report false recursion.
	*/
	static struct lock_class_key gpio_lock_class;

	static int __init tegra_gpio_init(void)
	{
	struct tegra_gpio_bank *bank;
	int i;
	int j;

	for (i = 0; i < 7; i++) {
	for (j = 0; j < 4; j++) {
	int gpio = tegra_gpio_compose(i, j, 0);
	__raw_writel(0x00, GPIO_INT_ENB(gpio));
	}
	}

	gpiochip_add(&tegra_gpio_chip);

	for (i = INT_GPIO_BASE; i < (INT_GPIO_BASE + ARCH_NR_GPIOS); i++) {
	bank = &tegra_gpio_banks[GPIO_BANK(irq_to_gpio(i))];

	lockdep_set_class(&irq_desc[i].lock, &gpio_lock_class);
	set_irq_chip_data(i, bank);
	set_irq_chip(i, &tegra_gpio_irq_chip);
	set_irq_handler(i, handle_simple_irq);
	set_irq_flags(i, IRQF_VALID);
	}

	for (i = 0; i < ARRAY_SIZE(tegra_gpio_banks); i++) {
	bank = &tegra_gpio_banks[i];

	set_irq_chained_handler(bank->irq, tegra_gpio_irq_handler);
	set_irq_data(bank->irq, bank);

	for (j = 0; j < 4; j++)
	spin_lock_init(&bank->lvl_lock[j]);
	}

	return 0;
	}

	postcore_initcall(tegra_gpio_init);

	#ifdef CONFIG_DEBUG_FS

	#include <linux/debugfs.h>
	#include <linux/seq_file.h>

	static int dbg_gpio_show(struct seq_file s, void unused)
	{
	int i;
	int j;

	for (i = 0; i < 7; i++) {
	for (j = 0; j < 4; j++) {
	int gpio = tegra_gpio_compose(i, j, 0);
	seq_printf(s, "%d:%d %02x %02x %02x %02x %02x %02x %06x\n",
	i, j,
	__raw_readl(GPIO_CNF(gpio)),
	__raw_readl(GPIO_OE(gpio)),
	__raw_readl(GPIO_OUT(gpio)),
	__raw_readl(GPIO_IN(gpio)),
	__raw_readl(GPIO_INT_STA(gpio)),
	__raw_readl(GPIO_INT_ENB(gpio)),
	__raw_readl(GPIO_INT_LVL(gpio)));
	}
	}
	return 0;
	}

	static int dbg_gpio_open(struct inode inode, struct file file)
	{
	return single_open(file, dbg_gpio_show, &inode->i_private);
	}

	static const struct file_operations debug_fops = {
	.open = dbg_gpio_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	};

	static int __init tegra_gpio_debuginit(void)
	{
	(void) debugfs_create_file("tegra_gpio", S_IRUGO,
	NULL, NULL, &debug_fops);
	return 0;
	}
	late_initcall(tegra_gpio_debuginit);
	#endif