drivers/gpio/max732x.c - kernel/msm-4.9 - Gitiles

 /*
  *  max732x.c - I2C Port Expander with 8/16 I/O
  *
  *  Copyright (C) 2007 Marvell International Ltd.
  *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
  *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
  *
  *  Derived from drivers/gpio/pca953x.c
  *
  *  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; version 2 of the License.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/gpio.h>

 #include <linux/i2c.h>
 #include <linux/i2c/max732x.h>


 /*
  * Each port of MAX732x (including MAX7319) falls into one of the
  * following three types:
  *
  *   - Push Pull Output
  *   - Input
  *   - Open Drain I/O
  *
  * designated by 'O', 'I' and 'P' individually according to MAXIM's
  * datasheets.
  *
  * There are two groups of I/O ports, each group usually includes
  * up to 8 I/O ports, and is accessed by a specific I2C address:
  *
  *   - Group A : by I2C address 0b'110xxxx
  *   - Group B : by I2C address 0b'101xxxx
  *
  * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
  * address used also affects the initial state of output signals.
  *
  * Within each group of ports, there are five known combinations of
  * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
  * the detailed organization of these ports.
  *
  * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
  * and GPIOs from GROUP_A are numbered before those from GROUP_B
  * (if there are two groups).
  *
  * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
  * they are not supported by this driver.
  */

 #define PORT_NONE	0x0	/* '/' No Port */
 #define PORT_OUTPUT	0x1	/* 'O' Push-Pull, Output Only */
 #define PORT_INPUT	0x2	/* 'I' Input Only */
 #define PORT_OPENDRAIN	0x3	/* 'P' Open-Drain, I/O */

 #define IO_4I4O		0x5AA5	/* O7 O6 I5 I4 I3 I2 O1 O0 */
 #define IO_4P4O		0x5FF5	/* O7 O6 P5 P4 P3 P2 O1 O0 */
 #define IO_8I		0xAAAA	/* I7 I6 I5 I4 I3 I2 I1 I0 */
 #define IO_8P		0xFFFF	/* P7 P6 P5 P4 P3 P2 P1 P0 */
 #define IO_8O		0x5555	/* O7 O6 O5 O4 O3 O2 O1 O0 */

 #define GROUP_A(x)	((x) & 0xffff)	/* I2C Addr: 0b'110xxxx */
 #define GROUP_B(x)	((x) << 16)	/* I2C Addr: 0b'101xxxx */

 static const struct i2c_device_id max732x_id[] = {
 	{ "max7319", GROUP_A(IO_8I) },
 	{ "max7320", GROUP_B(IO_8O) },
 	{ "max7321", GROUP_A(IO_8P) },
 	{ "max7322", GROUP_A(IO_4I4O) },
 	{ "max7323", GROUP_A(IO_4P4O) },
 	{ "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
 	{ "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
 	{ "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
 	{ "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
 	{ },
 };
 MODULE_DEVICE_TABLE(i2c, max732x_id);

 struct max732x_chip {
 	struct gpio_chip gpio_chip;

 	struct i2c_client *client;	/* "main" client */
 	struct i2c_client *client_dummy;
 	struct i2c_client *client_group_a;
 	struct i2c_client *client_group_b;

 	unsigned int	mask_group_a;
 	unsigned int	dir_input;
 	unsigned int	dir_output;

 	struct mutex	lock;
 	uint8_t		reg_out[2];
 };

 static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
 {
 	struct i2c_client *client;
 	int ret;

 	client = group_a ? chip->client_group_a : chip->client_group_b;
 	ret = i2c_smbus_write_byte(client, val);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed writing\n");
 		return ret;
 	}

 	return 0;
 }

 static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
 {
 	struct i2c_client *client;
 	int ret;

 	client = group_a ? chip->client_group_a : chip->client_group_b;
 	ret = i2c_smbus_read_byte(client);
 	if (ret < 0) {
 		dev_err(&client->dev, "failed reading\n");
 		return ret;
 	}

 	*val = (uint8_t)ret;
 	return 0;
 }

 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
 {
 	return (1u << off) & chip->mask_group_a;
 }

 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 {
 	struct max732x_chip *chip;
 	uint8_t reg_val;
 	int ret;

 	chip = container_of(gc, struct max732x_chip, gpio_chip);

 	ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
 	if (ret < 0)
 		return 0;

 	return reg_val & (1u << (off & 0x7));
 }

 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
 {
 	struct max732x_chip *chip;
 	uint8_t reg_out, mask = 1u << (off & 0x7);
 	int ret;

 	chip = container_of(gc, struct max732x_chip, gpio_chip);

 	mutex_lock(&chip->lock);

 	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
 	reg_out = (val) ? reg_out | mask : reg_out & ~mask;

 	ret = max732x_write(chip, is_group_a(chip, off), reg_out);
 	if (ret < 0)
 		goto out;

 	/* update the shadow register then */
 	if (off > 7)
 		chip->reg_out[1] = reg_out;
 	else
 		chip->reg_out[0] = reg_out;
 out:
 	mutex_unlock(&chip->lock);
 }

 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
 {
 	struct max732x_chip *chip;
 	unsigned int mask = 1u << off;

 	chip = container_of(gc, struct max732x_chip, gpio_chip);

 	if ((mask & chip->dir_input) == 0) {
 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
 			chip->client->name, off);
 		return -EACCES;
 	}

 	return 0;
 }

 static int max732x_gpio_direction_output(struct gpio_chip *gc,
 		unsigned off, int val)
 {
 	struct max732x_chip *chip;
 	unsigned int mask = 1u << off;

 	chip = container_of(gc, struct max732x_chip, gpio_chip);

 	if ((mask & chip->dir_output) == 0) {
 		dev_dbg(&chip->client->dev, "%s port %d is input only\n",
 			chip->client->name, off);
 		return -EACCES;
 	}

 	max732x_gpio_set_value(gc, off, val);
 	return 0;
 }

 static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
 					const struct i2c_device_id *id,
 					unsigned gpio_start)
 {
 	struct gpio_chip *gc = &chip->gpio_chip;
 	uint32_t id_data = id->driver_data;
 	int i, port = 0;

 	for (i = 0; i < 16; i++, id_data >>= 2) {
 		unsigned int mask = 1 << port;

 		switch (id_data & 0x3) {
 		case PORT_OUTPUT:
 			chip->dir_output |= mask;
 			break;
 		case PORT_INPUT:
 			chip->dir_input |= mask;
 			break;
 		case PORT_OPENDRAIN:
 			chip->dir_output |= mask;
 			chip->dir_input |= mask;
 			break;
 		default:
 			continue;
 		}

 		if (i < 8)
 			chip->mask_group_a |= mask;
 		port++;
 	}

 	if (chip->dir_input)
 		gc->direction_input = max732x_gpio_direction_input;
 	if (chip->dir_output) {
 		gc->direction_output = max732x_gpio_direction_output;
 		gc->set = max732x_gpio_set_value;
 	}
 	gc->get = max732x_gpio_get_value;
 	gc->can_sleep = 1;

 	gc->base = gpio_start;
 	gc->ngpio = port;
 	gc->label = chip->client->name;
 	gc->owner = THIS_MODULE;

 	return port;
 }

 static int __devinit max732x_probe(struct i2c_client *client,
 				   const struct i2c_device_id *id)
 {
 	struct max732x_platform_data *pdata;
 	struct max732x_chip *chip;
 	struct i2c_client *c;
 	uint16_t addr_a, addr_b;
 	int ret, nr_port;

 	pdata = client->dev.platform_data;
 	if (pdata == NULL) {
 		dev_dbg(&client->dev, "no platform data\n");
 		return -EINVAL;
 	}

 	chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
 	if (chip == NULL)
 		return -ENOMEM;
 	chip->client = client;

 	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);

 	addr_a = (client->addr & 0x0f) | 0x60;
 	addr_b = (client->addr & 0x0f) | 0x50;

 	switch (client->addr & 0x70) {
 	case 0x60:
 		chip->client_group_a = client;
 		if (nr_port > 7) {
 			c = i2c_new_dummy(client->adapter, addr_b);
 			chip->client_group_b = chip->client_dummy = c;
 		}
 		break;
 	case 0x50:
 		chip->client_group_b = client;
 		if (nr_port > 7) {
 			c = i2c_new_dummy(client->adapter, addr_a);
 			chip->client_group_a = chip->client_dummy = c;
 		}
 		break;
 	default:
 		dev_err(&client->dev, "invalid I2C address specified %02x\n",
 				client->addr);
 		ret = -EINVAL;
 		goto out_failed;
 	}

 	mutex_init(&chip->lock);

 	max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
 	if (nr_port > 7)
 		max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);

 	ret = gpiochip_add(&chip->gpio_chip);
 	if (ret)
 		goto out_failed;

 	if (pdata->setup) {
 		ret = pdata->setup(client, chip->gpio_chip.base,
 				chip->gpio_chip.ngpio, pdata->context);
 		if (ret < 0)
 			dev_warn(&client->dev, "setup failed, %d\n", ret);
 	}

 	i2c_set_clientdata(client, chip);
 	return 0;

 out_failed:
 	kfree(chip);
 	return ret;
 }

 static int __devexit max732x_remove(struct i2c_client *client)
 {
 	struct max732x_platform_data *pdata = client->dev.platform_data;
 	struct max732x_chip *chip = i2c_get_clientdata(client);
 	int ret;

 	if (pdata->teardown) {
 		ret = pdata->teardown(client, chip->gpio_chip.base,
 				chip->gpio_chip.ngpio, pdata->context);
 		if (ret < 0) {
 			dev_err(&client->dev, "%s failed, %d\n",
 					"teardown", ret);
 			return ret;
 		}
 	}

 	ret = gpiochip_remove(&chip->gpio_chip);
 	if (ret) {
 		dev_err(&client->dev, "%s failed, %d\n",
 				"gpiochip_remove()", ret);
 		return ret;
 	}

 	/* unregister any dummy i2c_client */
 	if (chip->client_dummy)
 		i2c_unregister_device(chip->client_dummy);

 	kfree(chip);
 	return 0;
 }

 static struct i2c_driver max732x_driver = {
 	.driver = {
 		.name	= "max732x",
 		.owner	= THIS_MODULE,
 	},
 	.probe		= max732x_probe,
 	.remove		= __devexit_p(max732x_remove),
 	.id_table	= max732x_id,
 };

 static int __init max732x_init(void)
 {
 	return i2c_add_driver(&max732x_driver);
 }
 /* register after i2c postcore initcall and before
  * subsys initcalls that may rely on these GPIOs
  */
 subsys_initcall(max732x_init);

 static void __exit max732x_exit(void)
 {
 	i2c_del_driver(&max732x_driver);
 }
 module_exit(max732x_exit);

 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
 MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
 MODULE_LICENSE("GPL");
	/*
	* max732x.c - I2C Port Expander with 8/16 I/O
	*
	* Copyright (C) 2007 Marvell International Ltd.
	* Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
	* Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
	*
	* Derived from drivers/gpio/pca953x.c
	*
	* 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; version 2 of the License.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/string.h>
	#include <linux/gpio.h>

	#include <linux/i2c.h>
	#include <linux/i2c/max732x.h>


	/*
	* Each port of MAX732x (including MAX7319) falls into one of the
	* following three types:
	*
	* - Push Pull Output
	* - Input
	* - Open Drain I/O
	*
	* designated by 'O', 'I' and 'P' individually according to MAXIM's
	* datasheets.
	*
	* There are two groups of I/O ports, each group usually includes
	* up to 8 I/O ports, and is accessed by a specific I2C address:
	*
	* - Group A : by I2C address 0b'110xxxx
	* - Group B : by I2C address 0b'101xxxx
	*
	* where 'xxxx' is decided by the connections of pin AD2/AD0. The
	* address used also affects the initial state of output signals.
	*
	* Within each group of ports, there are five known combinations of
	* I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
	* the detailed organization of these ports.
	*
	* GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
	* and GPIOs from GROUP_A are numbered before those from GROUP_B
	* (if there are two groups).
	*
	* NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
	* they are not supported by this driver.
	*/

	#define PORT_NONE 0x0 /* '/' No Port */
	#define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */
	#define PORT_INPUT 0x2 /* 'I' Input Only */
	#define PORT_OPENDRAIN 0x3 /* 'P' Open-Drain, I/O */

	#define IO_4I4O 0x5AA5 /* O7 O6 I5 I4 I3 I2 O1 O0 */
	#define IO_4P4O 0x5FF5 /* O7 O6 P5 P4 P3 P2 O1 O0 */
	#define IO_8I 0xAAAA /* I7 I6 I5 I4 I3 I2 I1 I0 */
	#define IO_8P 0xFFFF /* P7 P6 P5 P4 P3 P2 P1 P0 */
	#define IO_8O 0x5555 /* O7 O6 O5 O4 O3 O2 O1 O0 */

	#define GROUP_A(x) ((x) & 0xffff) /* I2C Addr: 0b'110xxxx */
	#define GROUP_B(x) ((x) << 16) /* I2C Addr: 0b'101xxxx */

	static const struct i2c_device_id max732x_id[] = {
	{ "max7319", GROUP_A(IO_8I) },
	{ "max7320", GROUP_B(IO_8O) },
	{ "max7321", GROUP_A(IO_8P) },
	{ "max7322", GROUP_A(IO_4I4O) },
	{ "max7323", GROUP_A(IO_4P4O) },
	{ "max7324", GROUP_A(IO_8I) \| GROUP_B(IO_8O) },
	{ "max7325", GROUP_A(IO_8P) \| GROUP_B(IO_8O) },
	{ "max7326", GROUP_A(IO_4I4O) \| GROUP_B(IO_8O) },
	{ "max7327", GROUP_A(IO_4P4O) \| GROUP_B(IO_8O) },
	{ },
	};
	MODULE_DEVICE_TABLE(i2c, max732x_id);

	struct max732x_chip {
	struct gpio_chip gpio_chip;

	struct i2c_client client; / "main" client */
	struct i2c_client *client_dummy;
	struct i2c_client *client_group_a;
	struct i2c_client *client_group_b;

	unsigned int mask_group_a;
	unsigned int dir_input;
	unsigned int dir_output;

	struct mutex lock;
	uint8_t reg_out[2];
	};

	static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
	{
	struct i2c_client *client;
	int ret;

	client = group_a ? chip->client_group_a : chip->client_group_b;
	ret = i2c_smbus_write_byte(client, val);
	if (ret < 0) {
	dev_err(&client->dev, "failed writing\n");
	return ret;
	}

	return 0;
	}

	static int max732x_read(struct max732x_chip chip, int group_a, uint8_t val)
	{
	struct i2c_client *client;
	int ret;

	client = group_a ? chip->client_group_a : chip->client_group_b;
	ret = i2c_smbus_read_byte(client);
	if (ret < 0) {
	dev_err(&client->dev, "failed reading\n");
	return ret;
	}

	*val = (uint8_t)ret;
	return 0;
	}

	static inline int is_group_a(struct max732x_chip *chip, unsigned off)
	{
	return (1u << off) & chip->mask_group_a;
	}

	static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
	{
	struct max732x_chip *chip;
	uint8_t reg_val;
	int ret;

	chip = container_of(gc, struct max732x_chip, gpio_chip);

	ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
	if (ret < 0)
	return 0;

	return reg_val & (1u << (off & 0x7));
	}

	static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
	{
	struct max732x_chip *chip;
	uint8_t reg_out, mask = 1u << (off & 0x7);
	int ret;

	chip = container_of(gc, struct max732x_chip, gpio_chip);

	mutex_lock(&chip->lock);

	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
	reg_out = (val) ? reg_out \| mask : reg_out & ~mask;

	ret = max732x_write(chip, is_group_a(chip, off), reg_out);
	if (ret < 0)
	goto out;

	/* update the shadow register then */
	if (off > 7)
	chip->reg_out[1] = reg_out;
	else
	chip->reg_out[0] = reg_out;
	out:
	mutex_unlock(&chip->lock);
	}

	static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
	{
	struct max732x_chip *chip;
	unsigned int mask = 1u << off;

	chip = container_of(gc, struct max732x_chip, gpio_chip);

	if ((mask & chip->dir_input) == 0) {
	dev_dbg(&chip->client->dev, "%s port %d is output only\n",
	chip->client->name, off);
	return -EACCES;
	}

	return 0;
	}

	static int max732x_gpio_direction_output(struct gpio_chip *gc,
	unsigned off, int val)
	{
	struct max732x_chip *chip;
	unsigned int mask = 1u << off;

	chip = container_of(gc, struct max732x_chip, gpio_chip);

	if ((mask & chip->dir_output) == 0) {
	dev_dbg(&chip->client->dev, "%s port %d is input only\n",
	chip->client->name, off);
	return -EACCES;
	}

	max732x_gpio_set_value(gc, off, val);
	return 0;
	}

	static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
	const struct i2c_device_id *id,
	unsigned gpio_start)
	{
	struct gpio_chip *gc = &chip->gpio_chip;
	uint32_t id_data = id->driver_data;
	int i, port = 0;

	for (i = 0; i < 16; i++, id_data >>= 2) {
	unsigned int mask = 1 << port;

	switch (id_data & 0x3) {
	case PORT_OUTPUT:
	chip->dir_output \|= mask;
	break;
	case PORT_INPUT:
	chip->dir_input \|= mask;
	break;
	case PORT_OPENDRAIN:
	chip->dir_output \|= mask;
	chip->dir_input \|= mask;
	break;
	default:
	continue;
	}

	if (i < 8)
	chip->mask_group_a \|= mask;
	port++;
	}

	if (chip->dir_input)
	gc->direction_input = max732x_gpio_direction_input;
	if (chip->dir_output) {
	gc->direction_output = max732x_gpio_direction_output;
	gc->set = max732x_gpio_set_value;
	}
	gc->get = max732x_gpio_get_value;
	gc->can_sleep = 1;

	gc->base = gpio_start;
	gc->ngpio = port;
	gc->label = chip->client->name;
	gc->owner = THIS_MODULE;

	return port;
	}

	static int __devinit max732x_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct max732x_platform_data *pdata;
	struct max732x_chip *chip;
	struct i2c_client *c;
	uint16_t addr_a, addr_b;
	int ret, nr_port;

	pdata = client->dev.platform_data;
	if (pdata == NULL) {
	dev_dbg(&client->dev, "no platform data\n");
	return -EINVAL;
	}

	chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
	if (chip == NULL)
	return -ENOMEM;
	chip->client = client;

	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);

	addr_a = (client->addr & 0x0f) \| 0x60;
	addr_b = (client->addr & 0x0f) \| 0x50;

	switch (client->addr & 0x70) {
	case 0x60:
	chip->client_group_a = client;
	if (nr_port > 7) {
	c = i2c_new_dummy(client->adapter, addr_b);
	chip->client_group_b = chip->client_dummy = c;
	}
	break;
	case 0x50:
	chip->client_group_b = client;
	if (nr_port > 7) {
	c = i2c_new_dummy(client->adapter, addr_a);
	chip->client_group_a = chip->client_dummy = c;
	}
	break;
	default:
	dev_err(&client->dev, "invalid I2C address specified %02x\n",
	client->addr);
	ret = -EINVAL;
	goto out_failed;
	}

	mutex_init(&chip->lock);

	max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
	if (nr_port > 7)
	max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);

	ret = gpiochip_add(&chip->gpio_chip);
	if (ret)
	goto out_failed;

	if (pdata->setup) {
	ret = pdata->setup(client, chip->gpio_chip.base,
	chip->gpio_chip.ngpio, pdata->context);
	if (ret < 0)
	dev_warn(&client->dev, "setup failed, %d\n", ret);
	}

	i2c_set_clientdata(client, chip);
	return 0;

	out_failed:
	kfree(chip);
	return ret;
	}

	static int __devexit max732x_remove(struct i2c_client *client)
	{
	struct max732x_platform_data *pdata = client->dev.platform_data;
	struct max732x_chip *chip = i2c_get_clientdata(client);
	int ret;

	if (pdata->teardown) {
	ret = pdata->teardown(client, chip->gpio_chip.base,
	chip->gpio_chip.ngpio, pdata->context);
	if (ret < 0) {
	dev_err(&client->dev, "%s failed, %d\n",
	"teardown", ret);
	return ret;
	}
	}

	ret = gpiochip_remove(&chip->gpio_chip);
	if (ret) {
	dev_err(&client->dev, "%s failed, %d\n",
	"gpiochip_remove()", ret);
	return ret;
	}

	/* unregister any dummy i2c_client */
	if (chip->client_dummy)
	i2c_unregister_device(chip->client_dummy);

	kfree(chip);
	return 0;
	}

	static struct i2c_driver max732x_driver = {
	.driver = {
	.name = "max732x",
	.owner = THIS_MODULE,
	},
	.probe = max732x_probe,
	.remove = __devexit_p(max732x_remove),
	.id_table = max732x_id,
	};

	static int __init max732x_init(void)
	{
	return i2c_add_driver(&max732x_driver);
	}
	/* register after i2c postcore initcall and before
	* subsys initcalls that may rely on these GPIOs
	*/
	subsys_initcall(max732x_init);

	static void __exit max732x_exit(void)
	{
	i2c_del_driver(&max732x_driver);
	}
	module_exit(max732x_exit);

	MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
	MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
	MODULE_LICENSE("GPL");