1 files changed, 760 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
new file mode 100644
index 000000000000..c43b8ff626a7
--- /dev/null
+++ b/drivers/gpio/gpio-pca953x.c
@@ -0,0 +1,760 @@
+/*
+ *  PCA953x 4/8/16 bit I/O ports
+ *
+ *  Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
+ *  Copyright (C) 2007 Marvell International Ltd.
+ *
+ *  Derived from drivers/i2c/chips/pca9539.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/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/i2c.h>
+#include <linux/i2c/pca953x.h>
+#include <linux/slab.h>
+#ifdef CONFIG_OF_GPIO
+#include <linux/of_platform.h>
+#endif
+
+#define PCA953X_INPUT		0
+#define PCA953X_OUTPUT		1
+#define PCA953X_INVERT		2
+#define PCA953X_DIRECTION	3
+
+#define PCA957X_IN		0
+#define PCA957X_INVRT		1
+#define PCA957X_BKEN		2
+#define PCA957X_PUPD		3
+#define PCA957X_CFG		4
+#define PCA957X_OUT		5
+#define PCA957X_MSK		6
+#define PCA957X_INTS		7
+
+#define PCA_GPIO_MASK		0x00FF
+#define PCA_INT			0x0100
+#define PCA953X_TYPE		0x1000
+#define PCA957X_TYPE		0x2000
+
+static const struct i2c_device_id pca953x_id[] = {
+	{ "pca9534", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "pca9535", 16 | PCA953X_TYPE | PCA_INT, },
+	{ "pca9536", 4  | PCA953X_TYPE, },
+	{ "pca9537", 4  | PCA953X_TYPE | PCA_INT, },
+	{ "pca9538", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "pca9539", 16 | PCA953X_TYPE | PCA_INT, },
+	{ "pca9554", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "pca9555", 16 | PCA953X_TYPE | PCA_INT, },
+	{ "pca9556", 8  | PCA953X_TYPE, },
+	{ "pca9557", 8  | PCA953X_TYPE, },
+	{ "pca9574", 8  | PCA957X_TYPE | PCA_INT, },
+	{ "pca9575", 16 | PCA957X_TYPE | PCA_INT, },
+
+	{ "max7310", 8  | PCA953X_TYPE, },
+	{ "max7312", 16 | PCA953X_TYPE | PCA_INT, },
+	{ "max7313", 16 | PCA953X_TYPE | PCA_INT, },
+	{ "max7315", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "pca6107", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "tca6408", 8  | PCA953X_TYPE | PCA_INT, },
+	{ "tca6416", 16 | PCA953X_TYPE | PCA_INT, },
+	/* NYET:  { "tca6424", 24, }, */
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, pca953x_id);
+
+struct pca953x_chip {
+	unsigned gpio_start;
+	uint16_t reg_output;
+	uint16_t reg_direction;
+	struct mutex i2c_lock;
+
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+	struct mutex irq_lock;
+	uint16_t irq_mask;
+	uint16_t irq_stat;
+	uint16_t irq_trig_raise;
+	uint16_t irq_trig_fall;
+	int	 irq_base;
+#endif
+
+	struct i2c_client *client;
+	struct gpio_chip gpio_chip;
+	const char *const *names;
+	int	chip_type;
+};
+
+static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
+{
+	int ret = 0;
+
+	if (chip->gpio_chip.ngpio <= 8)
+		ret = i2c_smbus_write_byte_data(chip->client, reg, val);
+	else {
+		switch (chip->chip_type) {
+		case PCA953X_TYPE:
+			ret = i2c_smbus_write_word_data(chip->client,
+							reg << 1, val);
+			break;
+		case PCA957X_TYPE:
+			ret = i2c_smbus_write_byte_data(chip->client, reg << 1,
+							val & 0xff);
+			if (ret < 0)
+				break;
+			ret = i2c_smbus_write_byte_data(chip->client,
+							(reg << 1) + 1,
+							(val & 0xff00) >> 8);
+			break;
+		}
+	}
+
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "failed writing register\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
+{
+	int ret;
+
+	if (chip->gpio_chip.ngpio <= 8)
+		ret = i2c_smbus_read_byte_data(chip->client, reg);
+	else
+		ret = i2c_smbus_read_word_data(chip->client, reg << 1);
+
+	if (ret < 0) {
+		dev_err(&chip->client->dev, "failed reading register\n");
+		return ret;
+	}
+
+	*val = (uint16_t)ret;
+	return 0;
+}
+
+static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
+{
+	struct pca953x_chip *chip;
+	uint16_t reg_val;
+	int ret, offset = 0;
+
+	chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+	mutex_lock(&chip->i2c_lock);
+	reg_val = chip->reg_direction | (1u << off);
+
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_DIRECTION;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_CFG;
+		break;
+	}
+	ret = pca953x_write_reg(chip, offset, reg_val);
+	if (ret)
+		goto exit;
+
+	chip->reg_direction = reg_val;
+	ret = 0;
+exit:
+	mutex_unlock(&chip->i2c_lock);
+	return ret;
+}
+
+static int pca953x_gpio_direction_output(struct gpio_chip *gc,
+		unsigned off, int val)
+{
+	struct pca953x_chip *chip;
+	uint16_t reg_val;
+	int ret, offset = 0;
+
+	chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+	mutex_lock(&chip->i2c_lock);
+	/* set output level */
+	if (val)
+		reg_val = chip->reg_output | (1u << off);
+	else
+		reg_val = chip->reg_output & ~(1u << off);
+
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_OUTPUT;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_OUT;
+		break;
+	}
+	ret = pca953x_write_reg(chip, offset, reg_val);
+	if (ret)
+		goto exit;
+
+	chip->reg_output = reg_val;
+
+	/* then direction */
+	reg_val = chip->reg_direction & ~(1u << off);
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_DIRECTION;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_CFG;
+		break;
+	}
+	ret = pca953x_write_reg(chip, offset, reg_val);
+	if (ret)
+		goto exit;
+
+	chip->reg_direction = reg_val;
+	ret = 0;
+exit:
+	mutex_unlock(&chip->i2c_lock);
+	return ret;
+}
+
+static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
+{
+	struct pca953x_chip *chip;
+	uint16_t reg_val;
+	int ret, offset = 0;
+
+	chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+	mutex_lock(&chip->i2c_lock);
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_INPUT;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_IN;
+		break;
+	}
+	ret = pca953x_read_reg(chip, offset, &reg_val);
+	mutex_unlock(&chip->i2c_lock);
+	if (ret < 0) {
+		/* NOTE:  diagnostic already emitted; that's all we should
+		 * do unless gpio_*_value_cansleep() calls become different
+		 * from their nonsleeping siblings (and report faults).
+		 */
+		return 0;
+	}
+
+	return (reg_val & (1u << off)) ? 1 : 0;
+}
+
+static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
+{
+	struct pca953x_chip *chip;
+	uint16_t reg_val;
+	int ret, offset = 0;
+
+	chip = container_of(gc, struct pca953x_chip, gpio_chip);
+
+	mutex_lock(&chip->i2c_lock);
+	if (val)
+		reg_val = chip->reg_output | (1u << off);
+	else
+		reg_val = chip->reg_output & ~(1u << off);
+
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_OUTPUT;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_OUT;
+		break;
+	}
+	ret = pca953x_write_reg(chip, offset, reg_val);
+	if (ret)
+		goto exit;
+
+	chip->reg_output = reg_val;
+exit:
+	mutex_unlock(&chip->i2c_lock);
+}
+
+static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
+{
+	struct gpio_chip *gc;
+
+	gc = &chip->gpio_chip;
+
+	gc->direction_input  = pca953x_gpio_direction_input;
+	gc->direction_output = pca953x_gpio_direction_output;
+	gc->get = pca953x_gpio_get_value;
+	gc->set = pca953x_gpio_set_value;
+	gc->can_sleep = 1;
+
+	gc->base = chip->gpio_start;
+	gc->ngpio = gpios;
+	gc->label = chip->client->name;
+	gc->dev = &chip->client->dev;
+	gc->owner = THIS_MODULE;
+	gc->names = chip->names;
+}
+
+#ifdef CONFIG_GPIO_PCA953X_IRQ
+static int pca953x_gpio_to_irq(struct gpio_chip *gc, unsigned off)
+{
+	struct pca953x_chip *chip;
+
+	chip = container_of(gc, struct pca953x_chip, gpio_chip);
+	return chip->irq_base + off;
+}
+
+static void pca953x_irq_mask(struct irq_data *d)
+{
+	struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
+
+	chip->irq_mask &= ~(1 << (d->irq - chip->irq_base));
+}
+
+static void pca953x_irq_unmask(struct irq_data *d)
+{
+	struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
+
+	chip->irq_mask |= 1 << (d->irq - chip->irq_base);
+}
+
+static void pca953x_irq_bus_lock(struct irq_data *d)
+{
+	struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
+
+	mutex_lock(&chip->irq_lock);
+}
+
+static void pca953x_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
+	uint16_t new_irqs;
+	uint16_t level;
+
+	/* Look for any newly setup interrupt */
+	new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
+	new_irqs &= ~chip->reg_direction;
+
+	while (new_irqs) {
+		level = __ffs(new_irqs);
+		pca953x_gpio_direction_input(&chip->gpio_chip, level);
+		new_irqs &= ~(1 << level);
+	}
+
+	mutex_unlock(&chip->irq_lock);
+}
+
+static int pca953x_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
+	uint16_t level = d->irq - chip->irq_base;
+	uint16_t mask = 1 << level;
+
+	if (!(type & IRQ_TYPE_EDGE_BOTH)) {
+		dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
+			d->irq, type);
+		return -EINVAL;
+	}
+
+	if (type & IRQ_TYPE_EDGE_FALLING)
+		chip->irq_trig_fall |= mask;
+	else
+		chip->irq_trig_fall &= ~mask;
+
+	if (type & IRQ_TYPE_EDGE_RISING)
+		chip->irq_trig_raise |= mask;
+	else
+		chip->irq_trig_raise &= ~mask;
+
+	return 0;
+}
+
+static struct irq_chip pca953x_irq_chip = {
+	.name			= "pca953x",
+	.irq_mask		= pca953x_irq_mask,
+	.irq_unmask		= pca953x_irq_unmask,
+	.irq_bus_lock		= pca953x_irq_bus_lock,
+	.irq_bus_sync_unlock	= pca953x_irq_bus_sync_unlock,
+	.irq_set_type		= pca953x_irq_set_type,
+};
+
+static uint16_t pca953x_irq_pending(struct pca953x_chip *chip)
+{
+	uint16_t cur_stat;
+	uint16_t old_stat;
+	uint16_t pending;
+	uint16_t trigger;
+	int ret, offset = 0;
+
+	switch (chip->chip_type) {
+	case PCA953X_TYPE:
+		offset = PCA953X_INPUT;
+		break;
+	case PCA957X_TYPE:
+		offset = PCA957X_IN;
+		break;
+	}
+	ret = pca953x_read_reg(chip, offset, &cur_stat);
+	if (ret)
+		return 0;
+
+	/* Remove output pins from the equation */
+	cur_stat &= chip->reg_direction;
+
+	old_stat = chip->irq_stat;
+	trigger = (cur_stat ^ old_stat) & chip->irq_mask;
+
+	if (!trigger)
+		return 0;
+
+	chip->irq_stat = cur_stat;
+
+	pending = (old_stat & chip->irq_trig_fall) |
+		  (cur_stat & chip->irq_trig_raise);
+	pending &= trigger;
+
+	return pending;
+}
+
+static irqreturn_t pca953x_irq_handler(int irq, void *devid)
+{
+	struct pca953x_chip *chip = devid;
+	uint16_t pending;
+	uint16_t level;
+
+	pending = pca953x_irq_pending(chip);
+
+	if (!pending)
+		return IRQ_HANDLED;
+
+	do {
+		level = __ffs(pending);
+		handle_nested_irq(level + chip->irq_base);
+
+		pending &= ~(1 << level);
+	} while (pending);
+
+	return IRQ_HANDLED;
+}
+
+static int pca953x_irq_setup(struct pca953x_chip *chip,
+			     const struct i2c_device_id *id,
+			     int irq_base)
+{
+	struct i2c_client *client = chip->client;
+	int ret, offset = 0;
+
+	if (irq_base != -1
+			&& (id->driver_data & PCA_INT)) {
+		int lvl;
+
+		switch (chip->chip_type) {
+		case PCA953X_TYPE:
+			offset = PCA953X_INPUT;
+			break;
+		case PCA957X_TYPE:
+			offset = PCA957X_IN;
+			break;
+		}
+		ret = pca953x_read_reg(chip, offset, &chip->irq_stat);
+		if (ret)
+			goto out_failed;
+
+		/*
+		 * There is no way to know which GPIO line generated the
+		 * interrupt.  We have to rely on the previous read for
+		 * this purpose.
+		 */
+		chip->irq_stat &= chip->reg_direction;
+		mutex_init(&chip->irq_lock);
+
+		chip->irq_base = irq_alloc_descs(-1, irq_base, chip->gpio_chip.ngpio, -1);
+		if (chip->irq_base < 0)
+			goto out_failed;
+
+		for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
+			int irq = lvl + chip->irq_base;
+
+			irq_clear_status_flags(irq, IRQ_NOREQUEST);
+			irq_set_chip_data(irq, chip);
+			irq_set_chip(irq, &pca953x_irq_chip);
+			irq_set_nested_thread(irq, true);
+#ifdef CONFIG_ARM
+			set_irq_flags(irq, IRQF_VALID);
+#else
+			irq_set_noprobe(irq);
+#endif
+		}
+
+		ret = request_threaded_irq(client->irq,
+					   NULL,
+					   pca953x_irq_handler,
+					   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+					   dev_name(&client->dev), chip);
+		if (ret) {
+			dev_err(&client->dev, "failed to request irq %d\n",
+				client->irq);
+			goto out_failed;
+		}
+
+		chip->gpio_chip.to_irq = pca953x_gpio_to_irq;
+	}
+
+	return 0;
+
+out_failed:
+	chip->irq_base = -1;
+	return ret;
+}
+
+static void pca953x_irq_teardown(struct pca953x_chip *chip)
+{
+	if (chip->irq_base != -1) {
+		irq_free_descs(chip->irq_base, chip->gpio_chip.ngpio);
+		free_irq(chip->client->irq, chip);
+	}
+}
+#else /* CONFIG_GPIO_PCA953X_IRQ */
+static int pca953x_irq_setup(struct pca953x_chip *chip,
+			     const struct i2c_device_id *id,
+			     int irq_base)
+{
+	struct i2c_client *client = chip->client;
+
+	if (irq_base != -1 && (id->driver_data & PCA_INT))
+		dev_warn(&client->dev, "interrupt support not compiled in\n");
+
+	return 0;
+}
+
+static void pca953x_irq_teardown(struct pca953x_chip *chip)
+{
+}
+#endif
+
+/*
+ * Handlers for alternative sources of platform_data
+ */
+#ifdef CONFIG_OF_GPIO
+/*
+ * Translate OpenFirmware node properties into platform_data
+ * WARNING: This is DEPRECATED and will be removed eventually!
+ */
+void
+pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
+{
+	struct device_node *node;
+	const __be32 *val;
+	int size;
+
+	node = client->dev.of_node;
+	if (node == NULL)
+		return;
+
+	*gpio_base = -1;
+	val = of_get_property(node, "linux,gpio-base", &size);
+	WARN(val, "%s: device-tree property 'linux,gpio-base' is deprecated!", __func__);
+	if (val) {
+		if (size != sizeof(*val))
+			dev_warn(&client->dev, "%s: wrong linux,gpio-base\n",
+				 node->full_name);
+		else
+			*gpio_base = be32_to_cpup(val);
+	}
+
+	val = of_get_property(node, "polarity", NULL);
+	WARN(val, "%s: device-tree property 'polarity' is deprecated!", __func__);
+	if (val)
+		*invert = *val;
+}
+#else
+void
+pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
+{
+}
+#endif
+
+static int __devinit device_pca953x_init(struct pca953x_chip *chip, int invert)
+{
+	int ret;
+
+	ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
+	if (ret)
+		goto out;
+
+	ret = pca953x_read_reg(chip, PCA953X_DIRECTION,
+			       &chip->reg_direction);
+	if (ret)
+		goto out;
+
+	/* set platform specific polarity inversion */
+	ret = pca953x_write_reg(chip, PCA953X_INVERT, invert);
+	if (ret)
+		goto out;
+	return 0;
+out:
+	return ret;
+}
+
+static int __devinit device_pca957x_init(struct pca953x_chip *chip, int invert)
+{
+	int ret;
+	uint16_t val = 0;
+
+	/* Let every port in proper state, that could save power */
+	pca953x_write_reg(chip, PCA957X_PUPD, 0x0);
+	pca953x_write_reg(chip, PCA957X_CFG, 0xffff);
+	pca953x_write_reg(chip, PCA957X_OUT, 0x0);
+
+	ret = pca953x_read_reg(chip, PCA957X_IN, &val);
+	if (ret)
+		goto out;
+	ret = pca953x_read_reg(chip, PCA957X_OUT, &chip->reg_output);
+	if (ret)
+		goto out;
+	ret = pca953x_read_reg(chip, PCA957X_CFG, &chip->reg_direction);
+	if (ret)
+		goto out;
+
+	/* set platform specific polarity inversion */
+	pca953x_write_reg(chip, PCA957X_INVRT, invert);
+
+	/* To enable register 6, 7 to controll pull up and pull down */
+	pca953x_write_reg(chip, PCA957X_BKEN, 0x202);
+
+	return 0;
+out:
+	return ret;
+}
+
+static int __devinit pca953x_probe(struct i2c_client *client,
+				   const struct i2c_device_id *id)
+{
+	struct pca953x_platform_data *pdata;
+	struct pca953x_chip *chip;
+	int irq_base=0, invert=0;
+	int ret = 0;
+
+	chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
+	if (chip == NULL)
+		return -ENOMEM;
+
+	pdata = client->dev.platform_data;
+	if (pdata) {
+		irq_base = pdata->irq_base;
+		chip->gpio_start = pdata->gpio_base;
+		invert = pdata->invert;
+		chip->names = pdata->names;
+	} else {
+		pca953x_get_alt_pdata(client, &chip->gpio_start, &invert);
+#ifdef CONFIG_OF_GPIO
+		/* If I2C node has no interrupts property, disable GPIO interrupts */
+		if (of_find_property(client->dev.of_node, "interrupts", NULL) == NULL)
+			irq_base = -1;
+#endif
+	}
+
+	chip->client = client;
+
+	chip->chip_type = id->driver_data & (PCA953X_TYPE | PCA957X_TYPE);
+
+	mutex_init(&chip->i2c_lock);
+
+	/* initialize cached registers from their original values.
+	 * we can't share this chip with another i2c master.
+	 */
+	pca953x_setup_gpio(chip, id->driver_data & PCA_GPIO_MASK);
+
+	if (chip->chip_type == PCA953X_TYPE)
+		device_pca953x_init(chip, invert);
+	else if (chip->chip_type == PCA957X_TYPE)
+		device_pca957x_init(chip, invert);
+	else
+		goto out_failed;
+
+	ret = pca953x_irq_setup(chip, id, irq_base);
+	if (ret)
+		goto out_failed;
+
+	ret = gpiochip_add(&chip->gpio_chip);
+	if (ret)
+		goto out_failed_irq;
+
+	if (pdata && 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_irq:
+	pca953x_irq_teardown(chip);
+out_failed:
+	kfree(chip);
+	return ret;
+}
+
+static int pca953x_remove(struct i2c_client *client)
+{
+	struct pca953x_platform_data *pdata = client->dev.platform_data;
+	struct pca953x_chip *chip = i2c_get_clientdata(client);
+	int ret = 0;
+
+	if (pdata && 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;
+	}
+
+	pca953x_irq_teardown(chip);
+	kfree(chip);
+	return 0;
+}
+
+static struct i2c_driver pca953x_driver = {
+	.driver = {
+		.name	= "pca953x",
+	},
+	.probe		= pca953x_probe,
+	.remove		= pca953x_remove,
+	.id_table	= pca953x_id,
+};
+
+static int __init pca953x_init(void)
+{
+	return i2c_add_driver(&pca953x_driver);
+}
+/* register after i2c postcore initcall and before
+ * subsys initcalls that may rely on these GPIOs
+ */
+subsys_initcall(pca953x_init);
+
+static void __exit pca953x_exit(void)
+{
+	i2c_del_driver(&pca953x_driver);
+}
+module_exit(pca953x_exit);
+
+MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
+MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
+MODULE_LICENSE("GPL");