drivers/gpio/gpio-mockup.c - arm/linux - Git at Google

 /*
  * GPIO Testing Device Driver
  *
  * Copyright (C) 2014  Kamlakant Patel <kamlakant.patel@broadcom.com>
  * Copyright (C) 2015-2016  Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
  *
  * 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.
  *
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/gpio/driver.h>
 #include <linux/gpio/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irq_work.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>

 #include "gpiolib.h"

 #define GPIO_MOCKUP_NAME	"gpio-mockup"
 #define	GPIO_MOCKUP_MAX_GC	10

 enum {
 	DIR_IN = 0,
 	DIR_OUT,
 };

 /*
  * struct gpio_pin_status - structure describing a GPIO status
  * @dir:       Configures direction of gpio as "in" or "out", 0=in, 1=out
  * @value:     Configures status of the gpio as 0(low) or 1(high)
  */
 struct gpio_mockup_line_status {
 	int dir;
 	bool value;
 };

 struct gpio_mockup_irq_context {
 	struct irq_work work;
 	int irq;
 };

 struct gpio_mockup_chip {
 	struct gpio_chip gc;
 	struct gpio_mockup_line_status *lines;
 	struct gpio_mockup_irq_context irq_ctx;
 	struct dentry *dbg_dir;
 };

 struct gpio_mockup_dbgfs_private {
 	struct gpio_mockup_chip *chip;
 	struct gpio_desc *desc;
 	int offset;
 };

 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_GC << 1];
 static int gpio_mockup_params_nr;
 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);

 static bool gpio_mockup_named_lines;
 module_param_named(gpio_mockup_named_lines,
 		   gpio_mockup_named_lines, bool, 0400);

 static const char gpio_mockup_name_start = 'A';
 static struct dentry *gpio_mockup_dbg_dir;

 static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

 	return chip->lines[offset].value;
 }

 static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
 			    int value)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

 	chip->lines[offset].value = !!value;
 }

 static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
 			      int value)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

 	gpio_mockup_set(gc, offset, value);
 	chip->lines[offset].dir = DIR_OUT;

 	return 0;
 }

 static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

 	chip->lines[offset].dir = DIR_IN;

 	return 0;
 }

 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

 	return chip->lines[offset].dir;
 }

 static int gpio_mockup_name_lines(struct device *dev,
 				  struct gpio_mockup_chip *chip)
 {
 	struct gpio_chip *gc = &chip->gc;
 	char **names;
 	int i;

 	names = devm_kzalloc(dev, sizeof(char *) * gc->ngpio, GFP_KERNEL);
 	if (!names)
 		return -ENOMEM;

 	for (i = 0; i < gc->ngpio; i++) {
 		names[i] = devm_kasprintf(dev, GFP_KERNEL,
 					  "%s-%d", gc->label, i);
 		if (!names[i])
 			return -ENOMEM;
 	}

 	gc->names = (const char *const *)names;

 	return 0;
 }

 static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
 {
 	return chip->irq_base + offset;
 }

 /*
  * While we should generally support irqmask and irqunmask, this driver is
  * for testing purposes only so we don't care.
  */
 static void gpio_mockup_irqmask(struct irq_data *d) { }
 static void gpio_mockup_irqunmask(struct irq_data *d) { }

 static struct irq_chip gpio_mockup_irqchip = {
 	.name		= GPIO_MOCKUP_NAME,
 	.irq_mask	= gpio_mockup_irqmask,
 	.irq_unmask	= gpio_mockup_irqunmask,
 };

 static void gpio_mockup_handle_irq(struct irq_work *work)
 {
 	struct gpio_mockup_irq_context *irq_ctx;

 	irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
 	handle_simple_irq(irq_to_desc(irq_ctx->irq));
 }

 static int gpio_mockup_irqchip_setup(struct device *dev,
 				     struct gpio_mockup_chip *chip)
 {
 	struct gpio_chip *gc = &chip->gc;
 	int irq_base, i;

 	irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
 	if (irq_base < 0)
 		return irq_base;

 	gc->irq_base = irq_base;
 	gc->irqchip = &gpio_mockup_irqchip;

 	for (i = 0; i < gc->ngpio; i++) {
 		irq_set_chip(irq_base + i, gc->irqchip);
 		irq_set_handler(irq_base + i, &handle_simple_irq);
 		irq_modify_status(irq_base + i,
 				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
 	}

 	init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);

 	return 0;
 }

 static ssize_t gpio_mockup_event_write(struct file *file,
 				       const char __user *usr_buf,
 				       size_t size, loff_t *ppos)
 {
 	struct gpio_mockup_dbgfs_private *priv;
 	struct gpio_mockup_chip *chip;
 	struct seq_file *sfile;
 	struct gpio_desc *desc;
 	struct gpio_chip *gc;
 	int val;
 	char buf;

 	sfile = file->private_data;
 	priv = sfile->private;
 	desc = priv->desc;
 	chip = priv->chip;
 	gc = &chip->gc;

 	if (copy_from_user(&buf, usr_buf, 1))
 		return -EFAULT;

 	if (buf == '0')
 		val = 0;
 	else if (buf == '1')
 		val = 1;
 	else
 		return -EINVAL;

 	gpiod_set_value_cansleep(desc, val);
 	priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
 	irq_work_queue(&priv->chip->irq_ctx.work);

 	return size;
 }

 static int gpio_mockup_event_open(struct inode *inode, struct file *file)
 {
 	return single_open(file, NULL, inode->i_private);
 }

 static const struct file_operations gpio_mockup_event_ops = {
 	.owner = THIS_MODULE,
 	.open = gpio_mockup_event_open,
 	.write = gpio_mockup_event_write,
 	.llseek = no_llseek,
 };

 static void gpio_mockup_debugfs_setup(struct device *dev,
 				      struct gpio_mockup_chip *chip)
 {
 	struct gpio_mockup_dbgfs_private *priv;
 	struct dentry *evfile;
 	struct gpio_chip *gc;
 	char *name;
 	int i;

 	gc = &chip->gc;

 	chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
 	if (!chip->dbg_dir)
 		goto err;

 	for (i = 0; i < gc->ngpio; i++) {
 		name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
 		if (!name)
 			goto err;

 		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 		if (!priv)
 			goto err;

 		priv->chip = chip;
 		priv->offset = i;
 		priv->desc = &gc->gpiodev->descs[i];

 		evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
 					     &gpio_mockup_event_ops);
 		if (!evfile)
 			goto err;
 	}

 	return;

 err:
 	dev_err(dev, "error creating debugfs directory\n");
 }

 static int gpio_mockup_add(struct device *dev,
 			   struct gpio_mockup_chip *chip,
 			   const char *name, int base, int ngpio)
 {
 	struct gpio_chip *gc = &chip->gc;
 	int ret;

 	gc->base = base;
 	gc->ngpio = ngpio;
 	gc->label = name;
 	gc->owner = THIS_MODULE;
 	gc->parent = dev;
 	gc->get = gpio_mockup_get;
 	gc->set = gpio_mockup_set;
 	gc->direction_output = gpio_mockup_dirout;
 	gc->direction_input = gpio_mockup_dirin;
 	gc->get_direction = gpio_mockup_get_direction;
 	gc->to_irq = gpio_mockup_to_irq;

 	chip->lines = devm_kzalloc(dev, sizeof(*chip->lines) * gc->ngpio,
 				   GFP_KERNEL);
 	if (!chip->lines)
 		return -ENOMEM;

 	if (gpio_mockup_named_lines) {
 		ret = gpio_mockup_name_lines(dev, chip);
 		if (ret)
 			return ret;
 	}

 	ret = gpio_mockup_irqchip_setup(dev, chip);
 	if (ret)
 		return ret;

 	ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
 	if (ret)
 		return ret;

 	if (gpio_mockup_dbg_dir)
 		gpio_mockup_debugfs_setup(dev, chip);

 	return 0;
 }

 static int gpio_mockup_probe(struct platform_device *pdev)
 {
 	struct gpio_mockup_chip *chips;
 	struct device *dev = &pdev->dev;
 	int ret, i, base, ngpio;
 	char *chip_name;

 	if (gpio_mockup_params_nr < 2)
 		return -EINVAL;

 	chips = devm_kzalloc(dev,
 			     sizeof(*chips) * (gpio_mockup_params_nr >> 1),
 			     GFP_KERNEL);
 	if (!chips)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, chips);

 	for (i = 0; i < gpio_mockup_params_nr >> 1; i++) {
 		base = gpio_mockup_ranges[i * 2];

 		if (base == -1)
 			ngpio = gpio_mockup_ranges[i * 2 + 1];
 		else
 			ngpio = gpio_mockup_ranges[i * 2 + 1] - base;

 		if (ngpio >= 0) {
 			chip_name = devm_kasprintf(dev, GFP_KERNEL,
 						   "%s-%c", GPIO_MOCKUP_NAME,
 						   gpio_mockup_name_start + i);
 			if (!chip_name)
 				return -ENOMEM;

 			ret = gpio_mockup_add(dev, &chips[i],
 					      chip_name, base, ngpio);
 		} else {
 			ret = -1;
 		}

 		if (ret) {
 			dev_err(dev, "gpio<%d..%d> add failed\n",
 				base, base < 0 ? ngpio : base + ngpio);

 			return ret;
 		}

 		dev_info(dev, "gpio<%d..%d> add successful!",
 			 base, base + ngpio);
 	}

 	return 0;
 }

 static struct platform_driver gpio_mockup_driver = {
 	.driver = {
 		.name = GPIO_MOCKUP_NAME,
 	},
 	.probe = gpio_mockup_probe,
 };

 static struct platform_device *pdev;
 static int __init mock_device_init(void)
 {
 	int err;

 	gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
 	if (!gpio_mockup_dbg_dir)
 		pr_err("%s: error creating debugfs directory\n",
 		       GPIO_MOCKUP_NAME);

 	pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
 	if (!pdev)
 		return -ENOMEM;

 	err = platform_device_add(pdev);
 	if (err) {
 		platform_device_put(pdev);
 		return err;
 	}

 	err = platform_driver_register(&gpio_mockup_driver);
 	if (err) {
 		platform_device_unregister(pdev);
 		return err;
 	}

 	return 0;
 }

 static void __exit mock_device_exit(void)
 {
 	debugfs_remove_recursive(gpio_mockup_dbg_dir);
 	platform_driver_unregister(&gpio_mockup_driver);
 	platform_device_unregister(pdev);
 }

 module_init(mock_device_init);
 module_exit(mock_device_exit);

 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
 MODULE_DESCRIPTION("GPIO Testing driver");
 MODULE_LICENSE("GPL v2");
	/*
	* GPIO Testing Device Driver
	*
	* Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
	* Copyright (C) 2015-2016 Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
	*
	* 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.
	*
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/gpio/driver.h>
	#include <linux/gpio/consumer.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/irq_work.h>
	#include <linux/debugfs.h>
	#include <linux/uaccess.h>

	#include "gpiolib.h"

	#define GPIO_MOCKUP_NAME "gpio-mockup"
	#define GPIO_MOCKUP_MAX_GC 10

	enum {
	DIR_IN = 0,
	DIR_OUT,
	};

	/*
	* struct gpio_pin_status - structure describing a GPIO status
	* @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
	* @value: Configures status of the gpio as 0(low) or 1(high)
	*/
	struct gpio_mockup_line_status {
	int dir;
	bool value;
	};

	struct gpio_mockup_irq_context {
	struct irq_work work;
	int irq;
	};

	struct gpio_mockup_chip {
	struct gpio_chip gc;
	struct gpio_mockup_line_status *lines;
	struct gpio_mockup_irq_context irq_ctx;
	struct dentry *dbg_dir;
	};

	struct gpio_mockup_dbgfs_private {
	struct gpio_mockup_chip *chip;
	struct gpio_desc *desc;
	int offset;
	};

	static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_GC << 1];
	static int gpio_mockup_params_nr;
	module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);

	static bool gpio_mockup_named_lines;
	module_param_named(gpio_mockup_named_lines,
	gpio_mockup_named_lines, bool, 0400);

	static const char gpio_mockup_name_start = 'A';
	static struct dentry *gpio_mockup_dbg_dir;

	static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
	{
	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

	return chip->lines[offset].value;
	}

	static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
	int value)
	{
	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

	chip->lines[offset].value = !!value;
	}

	static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
	int value)
	{
	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

	gpio_mockup_set(gc, offset, value);
	chip->lines[offset].dir = DIR_OUT;

	return 0;
	}

	static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
	{
	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

	chip->lines[offset].dir = DIR_IN;

	return 0;
	}

	static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
	{
	struct gpio_mockup_chip *chip = gpiochip_get_data(gc);

	return chip->lines[offset].dir;
	}

	static int gpio_mockup_name_lines(struct device *dev,
	struct gpio_mockup_chip *chip)
	{
	struct gpio_chip *gc = &chip->gc;
	char **names;
	int i;

	names = devm_kzalloc(dev, sizeof(char ) gc->ngpio, GFP_KERNEL);
	if (!names)
	return -ENOMEM;

	for (i = 0; i < gc->ngpio; i++) {
	names[i] = devm_kasprintf(dev, GFP_KERNEL,
	"%s-%d", gc->label, i);
	if (!names[i])
	return -ENOMEM;
	}

	gc->names = (const char const )names;

	return 0;
	}

	static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
	{
	return chip->irq_base + offset;
	}

	/*
	* While we should generally support irqmask and irqunmask, this driver is
	* for testing purposes only so we don't care.
	*/
	static void gpio_mockup_irqmask(struct irq_data *d) { }
	static void gpio_mockup_irqunmask(struct irq_data *d) { }

	static struct irq_chip gpio_mockup_irqchip = {
	.name = GPIO_MOCKUP_NAME,
	.irq_mask = gpio_mockup_irqmask,
	.irq_unmask = gpio_mockup_irqunmask,
	};

	static void gpio_mockup_handle_irq(struct irq_work *work)
	{
	struct gpio_mockup_irq_context *irq_ctx;

	irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
	handle_simple_irq(irq_to_desc(irq_ctx->irq));
	}

	static int gpio_mockup_irqchip_setup(struct device *dev,
	struct gpio_mockup_chip *chip)
	{
	struct gpio_chip *gc = &chip->gc;
	int irq_base, i;

	irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
	if (irq_base < 0)
	return irq_base;

	gc->irq_base = irq_base;
	gc->irqchip = &gpio_mockup_irqchip;

	for (i = 0; i < gc->ngpio; i++) {
	irq_set_chip(irq_base + i, gc->irqchip);
	irq_set_handler(irq_base + i, &handle_simple_irq);
	irq_modify_status(irq_base + i,
	IRQ_NOREQUEST \| IRQ_NOAUTOEN, IRQ_NOPROBE);
	}

	init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);

	return 0;
	}

	static ssize_t gpio_mockup_event_write(struct file *file,
	const char __user *usr_buf,
	size_t size, loff_t *ppos)
	{
	struct gpio_mockup_dbgfs_private *priv;
	struct gpio_mockup_chip *chip;
	struct seq_file *sfile;
	struct gpio_desc *desc;
	struct gpio_chip *gc;
	int val;
	char buf;

	sfile = file->private_data;
	priv = sfile->private;
	desc = priv->desc;
	chip = priv->chip;
	gc = &chip->gc;

	if (copy_from_user(&buf, usr_buf, 1))
	return -EFAULT;

	if (buf == '0')
	val = 0;
	else if (buf == '1')
	val = 1;
	else
	return -EINVAL;

	gpiod_set_value_cansleep(desc, val);
	priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
	irq_work_queue(&priv->chip->irq_ctx.work);

	return size;
	}

	static int gpio_mockup_event_open(struct inode inode, struct file file)
	{
	return single_open(file, NULL, inode->i_private);
	}

	static const struct file_operations gpio_mockup_event_ops = {
	.owner = THIS_MODULE,
	.open = gpio_mockup_event_open,
	.write = gpio_mockup_event_write,
	.llseek = no_llseek,
	};

	static void gpio_mockup_debugfs_setup(struct device *dev,
	struct gpio_mockup_chip *chip)
	{
	struct gpio_mockup_dbgfs_private *priv;
	struct dentry *evfile;
	struct gpio_chip *gc;
	char *name;
	int i;

	gc = &chip->gc;

	chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
	if (!chip->dbg_dir)
	goto err;

	for (i = 0; i < gc->ngpio; i++) {
	name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
	if (!name)
	goto err;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	goto err;

	priv->chip = chip;
	priv->offset = i;
	priv->desc = &gc->gpiodev->descs[i];

	evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
	&gpio_mockup_event_ops);
	if (!evfile)
	goto err;
	}

	return;

	err:
	dev_err(dev, "error creating debugfs directory\n");
	}

	static int gpio_mockup_add(struct device *dev,
	struct gpio_mockup_chip *chip,
	const char *name, int base, int ngpio)
	{
	struct gpio_chip *gc = &chip->gc;
	int ret;

	gc->base = base;
	gc->ngpio = ngpio;
	gc->label = name;
	gc->owner = THIS_MODULE;
	gc->parent = dev;
	gc->get = gpio_mockup_get;
	gc->set = gpio_mockup_set;
	gc->direction_output = gpio_mockup_dirout;
	gc->direction_input = gpio_mockup_dirin;
	gc->get_direction = gpio_mockup_get_direction;
	gc->to_irq = gpio_mockup_to_irq;

	chip->lines = devm_kzalloc(dev, sizeof(chip->lines) gc->ngpio,
	GFP_KERNEL);
	if (!chip->lines)
	return -ENOMEM;

	if (gpio_mockup_named_lines) {
	ret = gpio_mockup_name_lines(dev, chip);
	if (ret)
	return ret;
	}

	ret = gpio_mockup_irqchip_setup(dev, chip);
	if (ret)
	return ret;

	ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
	if (ret)
	return ret;

	if (gpio_mockup_dbg_dir)
	gpio_mockup_debugfs_setup(dev, chip);

	return 0;
	}

	static int gpio_mockup_probe(struct platform_device *pdev)
	{
	struct gpio_mockup_chip *chips;
	struct device *dev = &pdev->dev;
	int ret, i, base, ngpio;
	char *chip_name;

	if (gpio_mockup_params_nr < 2)
	return -EINVAL;

	chips = devm_kzalloc(dev,
	sizeof(chips) (gpio_mockup_params_nr >> 1),
	GFP_KERNEL);
	if (!chips)
	return -ENOMEM;

	platform_set_drvdata(pdev, chips);

	for (i = 0; i < gpio_mockup_params_nr >> 1; i++) {
	base = gpio_mockup_ranges[i * 2];

	if (base == -1)
	ngpio = gpio_mockup_ranges[i * 2 + 1];
	else
	ngpio = gpio_mockup_ranges[i * 2 + 1] - base;

	if (ngpio >= 0) {
	chip_name = devm_kasprintf(dev, GFP_KERNEL,
	"%s-%c", GPIO_MOCKUP_NAME,
	gpio_mockup_name_start + i);
	if (!chip_name)
	return -ENOMEM;

	ret = gpio_mockup_add(dev, &chips[i],
	chip_name, base, ngpio);
	} else {
	ret = -1;
	}

	if (ret) {
	dev_err(dev, "gpio<%d..%d> add failed\n",
	base, base < 0 ? ngpio : base + ngpio);

	return ret;
	}

	dev_info(dev, "gpio<%d..%d> add successful!",
	base, base + ngpio);
	}

	return 0;
	}

	static struct platform_driver gpio_mockup_driver = {
	.driver = {
	.name = GPIO_MOCKUP_NAME,
	},
	.probe = gpio_mockup_probe,
	};

	static struct platform_device *pdev;
	static int __init mock_device_init(void)
	{
	int err;

	gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
	if (!gpio_mockup_dbg_dir)
	pr_err("%s: error creating debugfs directory\n",
	GPIO_MOCKUP_NAME);

	pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
	if (!pdev)
	return -ENOMEM;

	err = platform_device_add(pdev);
	if (err) {
	platform_device_put(pdev);
	return err;
	}

	err = platform_driver_register(&gpio_mockup_driver);
	if (err) {
	platform_device_unregister(pdev);
	return err;
	}

	return 0;
	}

	static void __exit mock_device_exit(void)
	{
	debugfs_remove_recursive(gpio_mockup_dbg_dir);
	platform_driver_unregister(&gpio_mockup_driver);
	platform_device_unregister(pdev);
	}

	module_init(mock_device_init);
	module_exit(mock_device_exit);

	MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
	MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
	MODULE_DESCRIPTION("GPIO Testing driver");
	MODULE_LICENSE("GPL v2");