drivers/gpio/pca953x.c - kernel/msm-4.19 - Gitiles

 /*
  *  pca953x.c - 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>
 #include <linux/of_gpio.h>
 #endif

 #define PCA953X_INPUT          0
 #define PCA953X_OUTPUT         1
 #define PCA953X_INVERT         2
 #define PCA953X_DIRECTION      3

 #define PCA953X_GPIOS	       0x00FF
 #define PCA953X_INT	       0x0100

 static const struct i2c_device_id pca953x_id[] = {
 	{ "pca9534", 8  | PCA953X_INT, },
 	{ "pca9535", 16 | PCA953X_INT, },
 	{ "pca9536", 4, },
 	{ "pca9537", 4  | PCA953X_INT, },
 	{ "pca9538", 8  | PCA953X_INT, },
 	{ "pca9539", 16 | PCA953X_INT, },
 	{ "pca9554", 8  | PCA953X_INT, },
 	{ "pca9555", 16 | PCA953X_INT, },
 	{ "pca9556", 8, },
 	{ "pca9557", 8, },

 	{ "max7310", 8, },
 	{ "max7312", 16 | PCA953X_INT, },
 	{ "max7313", 16 | PCA953X_INT, },
 	{ "max7315", 8  | PCA953X_INT, },
 	{ "pca6107", 8  | PCA953X_INT, },
 	{ "tca6408", 8  | PCA953X_INT, },
 	{ "tca6416", 16 | PCA953X_INT, },
 	/* NYET:  { "tca6424", 24, }, */
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pca953x_id);

 struct pca953x_chip {
 	unsigned gpio_start;
 	uint16_t reg_output;
 	uint16_t reg_direction;

 #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 pca953x_platform_data *dyn_pdata;
 	struct gpio_chip gpio_chip;
 	char **names;
 };

 static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
 {
 	int ret;

 	if (chip->gpio_chip.ngpio <= 8)
 		ret = i2c_smbus_write_byte_data(chip->client, reg, val);
 	else
 		ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);

 	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;

 	chip = container_of(gc, struct pca953x_chip, gpio_chip);

 	reg_val = chip->reg_direction | (1u << off);
 	ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
 	if (ret)
 		return ret;

 	chip->reg_direction = reg_val;
 	return 0;
 }

 static int pca953x_gpio_direction_output(struct gpio_chip *gc,
 		unsigned off, int val)
 {
 	struct pca953x_chip *chip;
 	uint16_t reg_val;
 	int ret;

 	chip = container_of(gc, struct pca953x_chip, gpio_chip);

 	/* set output level */
 	if (val)
 		reg_val = chip->reg_output | (1u << off);
 	else
 		reg_val = chip->reg_output & ~(1u << off);

 	ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 	if (ret)
 		return ret;

 	chip->reg_output = reg_val;

 	/* then direction */
 	reg_val = chip->reg_direction & ~(1u << off);
 	ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
 	if (ret)
 		return ret;

 	chip->reg_direction = reg_val;
 	return 0;
 }

 static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
 {
 	struct pca953x_chip *chip;
 	uint16_t reg_val;
 	int ret;

 	chip = container_of(gc, struct pca953x_chip, gpio_chip);

 	ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
 	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;

 	chip = container_of(gc, struct pca953x_chip, gpio_chip);

 	if (val)
 		reg_val = chip->reg_output | (1u << off);
 	else
 		reg_val = chip->reg_output & ~(1u << off);

 	ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
 	if (ret)
 		return;

 	chip->reg_output = reg_val;
 }

 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(unsigned int irq)
 {
 	struct pca953x_chip *chip = get_irq_chip_data(irq);

 	chip->irq_mask &= ~(1 << (irq - chip->irq_base));
 }

 static void pca953x_irq_unmask(unsigned int irq)
 {
 	struct pca953x_chip *chip = get_irq_chip_data(irq);

 	chip->irq_mask |= 1 << (irq - chip->irq_base);
 }

 static void pca953x_irq_bus_lock(unsigned int irq)
 {
 	struct pca953x_chip *chip = get_irq_chip_data(irq);

 	mutex_lock(&chip->irq_lock);
 }

 static void pca953x_irq_bus_sync_unlock(unsigned int irq)
 {
 	struct pca953x_chip *chip = get_irq_chip_data(irq);

 	mutex_unlock(&chip->irq_lock);
 }

 static int pca953x_irq_set_type(unsigned int irq, unsigned int type)
 {
 	struct pca953x_chip *chip = get_irq_chip_data(irq);
 	uint16_t level = 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",
 			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 pca953x_gpio_direction_input(&chip->gpio_chip, level);
 }

 static struct irq_chip pca953x_irq_chip = {
 	.name			= "pca953x",
 	.mask			= pca953x_irq_mask,
 	.unmask			= pca953x_irq_unmask,
 	.bus_lock		= pca953x_irq_bus_lock,
 	.bus_sync_unlock	= pca953x_irq_bus_sync_unlock,
 	.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;

 	ret = pca953x_read_reg(chip, PCA953X_INPUT, &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)
 {
 	struct i2c_client *client = chip->client;
 	struct pca953x_platform_data *pdata = client->dev.platform_data;
 	int ret;

 	if (pdata->irq_base && (id->driver_data & PCA953X_INT)) {
 		int lvl;

 		ret = pca953x_read_reg(chip, PCA953X_INPUT,
 				       &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;
 		chip->irq_base = pdata->irq_base;
 		mutex_init(&chip->irq_lock);

 		for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
 			int irq = lvl + chip->irq_base;

 			set_irq_chip_data(irq, chip);
 			set_irq_chip_and_handler(irq, &pca953x_irq_chip,
 						 handle_edge_irq);
 			set_irq_nested_thread(irq, 1);
 #ifdef CONFIG_ARM
 			set_irq_flags(irq, IRQF_VALID);
 #else
 			set_irq_noprobe(irq);
 #endif
 		}

 		ret = request_threaded_irq(client->irq,
 					   NULL,
 					   pca953x_irq_handler,
 					   IRQF_TRIGGER_FALLING | 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 = 0;
 	return ret;
 }

 static void pca953x_irq_teardown(struct pca953x_chip *chip)
 {
 	if (chip->irq_base)
 		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)
 {
 	struct i2c_client *client = chip->client;
 	struct pca953x_platform_data *pdata = client->dev.platform_data;

 	if (pdata->irq_base && (id->driver_data & PCA953X_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
  */
 static struct pca953x_platform_data *
 pca953x_get_alt_pdata(struct i2c_client *client)
 {
 	struct pca953x_platform_data *pdata;
 	struct device_node *node;
 	const uint16_t *val;

 	node = dev_archdata_get_node(&client->dev.archdata);
 	if (node == NULL)
 		return NULL;

 	pdata = kzalloc(sizeof(struct pca953x_platform_data), GFP_KERNEL);
 	if (pdata == NULL) {
 		dev_err(&client->dev, "Unable to allocate platform_data\n");
 		return NULL;
 	}

 	pdata->gpio_base = -1;
 	val = of_get_property(node, "linux,gpio-base", NULL);
 	if (val) {
 		if (*val < 0)
 			dev_warn(&client->dev,
 				 "invalid gpio-base in device tree\n");
 		else
 			pdata->gpio_base = *val;
 	}

 	val = of_get_property(node, "polarity", NULL);
 	if (val)
 		pdata->invert = *val;

 	return pdata;
 }
 #else
 static struct pca953x_platform_data *
 pca953x_get_alt_pdata(struct i2c_client *client)
 {
 	return NULL;
 }
 #endif

 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 ret;

 	chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
 	if (chip == NULL)
 		return -ENOMEM;

 	pdata = client->dev.platform_data;
 	if (pdata == NULL) {
 		pdata = pca953x_get_alt_pdata(client);
 		/*
 		 * Unlike normal platform_data, this is allocated
 		 * dynamically and must be freed in the driver
 		 */
 		chip->dyn_pdata = pdata;
 	}

 	if (pdata == NULL) {
 		dev_dbg(&client->dev, "no platform data\n");
 		ret = -EINVAL;
 		goto out_failed;
 	}

 	chip->client = client;

 	chip->gpio_start = pdata->gpio_base;

 	chip->names = pdata->names;

 	/* initialize cached registers from their original values.
 	 * we can't share this chip with another i2c master.
 	 */
 	pca953x_setup_gpio(chip, id->driver_data & PCA953X_GPIOS);

 	ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
 	if (ret)
 		goto out_failed;

 	ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
 	if (ret)
 		goto out_failed;

 	/* set platform specific polarity inversion */
 	ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
 	if (ret)
 		goto out_failed;

 	ret = pca953x_irq_setup(chip, id);
 	if (ret)
 		goto out_failed;

 	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:
 	pca953x_irq_teardown(chip);
 	kfree(chip->dyn_pdata);
 	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->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->dyn_pdata);
 	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");
	/*
	* pca953x.c - 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>
	#include <linux/of_gpio.h>
	#endif

	#define PCA953X_INPUT 0
	#define PCA953X_OUTPUT 1
	#define PCA953X_INVERT 2
	#define PCA953X_DIRECTION 3

	#define PCA953X_GPIOS 0x00FF
	#define PCA953X_INT 0x0100

	static const struct i2c_device_id pca953x_id[] = {
	{ "pca9534", 8 \| PCA953X_INT, },
	{ "pca9535", 16 \| PCA953X_INT, },
	{ "pca9536", 4, },
	{ "pca9537", 4 \| PCA953X_INT, },
	{ "pca9538", 8 \| PCA953X_INT, },
	{ "pca9539", 16 \| PCA953X_INT, },
	{ "pca9554", 8 \| PCA953X_INT, },
	{ "pca9555", 16 \| PCA953X_INT, },
	{ "pca9556", 8, },
	{ "pca9557", 8, },

	{ "max7310", 8, },
	{ "max7312", 16 \| PCA953X_INT, },
	{ "max7313", 16 \| PCA953X_INT, },
	{ "max7315", 8 \| PCA953X_INT, },
	{ "pca6107", 8 \| PCA953X_INT, },
	{ "tca6408", 8 \| PCA953X_INT, },
	{ "tca6416", 16 \| PCA953X_INT, },
	/* NYET: { "tca6424", 24, }, */
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, pca953x_id);

	struct pca953x_chip {
	unsigned gpio_start;
	uint16_t reg_output;
	uint16_t reg_direction;

	#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 pca953x_platform_data *dyn_pdata;
	struct gpio_chip gpio_chip;
	char **names;
	};

	static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
	{
	int ret;

	if (chip->gpio_chip.ngpio <= 8)
	ret = i2c_smbus_write_byte_data(chip->client, reg, val);
	else
	ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);

	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;

	chip = container_of(gc, struct pca953x_chip, gpio_chip);

	reg_val = chip->reg_direction \| (1u << off);
	ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
	if (ret)
	return ret;

	chip->reg_direction = reg_val;
	return 0;
	}

	static int pca953x_gpio_direction_output(struct gpio_chip *gc,
	unsigned off, int val)
	{
	struct pca953x_chip *chip;
	uint16_t reg_val;
	int ret;

	chip = container_of(gc, struct pca953x_chip, gpio_chip);

	/* set output level */
	if (val)
	reg_val = chip->reg_output \| (1u << off);
	else
	reg_val = chip->reg_output & ~(1u << off);

	ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
	if (ret)
	return ret;

	chip->reg_output = reg_val;

	/* then direction */
	reg_val = chip->reg_direction & ~(1u << off);
	ret = pca953x_write_reg(chip, PCA953X_DIRECTION, reg_val);
	if (ret)
	return ret;

	chip->reg_direction = reg_val;
	return 0;
	}

	static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
	{
	struct pca953x_chip *chip;
	uint16_t reg_val;
	int ret;

	chip = container_of(gc, struct pca953x_chip, gpio_chip);

	ret = pca953x_read_reg(chip, PCA953X_INPUT, &reg_val);
	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;

	chip = container_of(gc, struct pca953x_chip, gpio_chip);

	if (val)
	reg_val = chip->reg_output \| (1u << off);
	else
	reg_val = chip->reg_output & ~(1u << off);

	ret = pca953x_write_reg(chip, PCA953X_OUTPUT, reg_val);
	if (ret)
	return;

	chip->reg_output = reg_val;
	}

	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(unsigned int irq)
	{
	struct pca953x_chip *chip = get_irq_chip_data(irq);

	chip->irq_mask &= ~(1 << (irq - chip->irq_base));
	}

	static void pca953x_irq_unmask(unsigned int irq)
	{
	struct pca953x_chip *chip = get_irq_chip_data(irq);

	chip->irq_mask \|= 1 << (irq - chip->irq_base);
	}

	static void pca953x_irq_bus_lock(unsigned int irq)
	{
	struct pca953x_chip *chip = get_irq_chip_data(irq);

	mutex_lock(&chip->irq_lock);
	}

	static void pca953x_irq_bus_sync_unlock(unsigned int irq)
	{
	struct pca953x_chip *chip = get_irq_chip_data(irq);

	mutex_unlock(&chip->irq_lock);
	}

	static int pca953x_irq_set_type(unsigned int irq, unsigned int type)
	{
	struct pca953x_chip *chip = get_irq_chip_data(irq);
	uint16_t level = 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",
	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 pca953x_gpio_direction_input(&chip->gpio_chip, level);
	}

	static struct irq_chip pca953x_irq_chip = {
	.name = "pca953x",
	.mask = pca953x_irq_mask,
	.unmask = pca953x_irq_unmask,
	.bus_lock = pca953x_irq_bus_lock,
	.bus_sync_unlock = pca953x_irq_bus_sync_unlock,
	.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;

	ret = pca953x_read_reg(chip, PCA953X_INPUT, &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)
	{
	struct i2c_client *client = chip->client;
	struct pca953x_platform_data *pdata = client->dev.platform_data;
	int ret;

	if (pdata->irq_base && (id->driver_data & PCA953X_INT)) {
	int lvl;

	ret = pca953x_read_reg(chip, PCA953X_INPUT,
	&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;
	chip->irq_base = pdata->irq_base;
	mutex_init(&chip->irq_lock);

	for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
	int irq = lvl + chip->irq_base;

	set_irq_chip_data(irq, chip);
	set_irq_chip_and_handler(irq, &pca953x_irq_chip,
	handle_edge_irq);
	set_irq_nested_thread(irq, 1);
	#ifdef CONFIG_ARM
	set_irq_flags(irq, IRQF_VALID);
	#else
	set_irq_noprobe(irq);
	#endif
	}

	ret = request_threaded_irq(client->irq,
	NULL,
	pca953x_irq_handler,
	IRQF_TRIGGER_FALLING \| 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 = 0;
	return ret;
	}

	static void pca953x_irq_teardown(struct pca953x_chip *chip)
	{
	if (chip->irq_base)
	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)
	{
	struct i2c_client *client = chip->client;
	struct pca953x_platform_data *pdata = client->dev.platform_data;

	if (pdata->irq_base && (id->driver_data & PCA953X_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
	*/
	static struct pca953x_platform_data *
	pca953x_get_alt_pdata(struct i2c_client *client)
	{
	struct pca953x_platform_data *pdata;
	struct device_node *node;
	const uint16_t *val;

	node = dev_archdata_get_node(&client->dev.archdata);
	if (node == NULL)
	return NULL;

	pdata = kzalloc(sizeof(struct pca953x_platform_data), GFP_KERNEL);
	if (pdata == NULL) {
	dev_err(&client->dev, "Unable to allocate platform_data\n");
	return NULL;
	}

	pdata->gpio_base = -1;
	val = of_get_property(node, "linux,gpio-base", NULL);
	if (val) {
	if (*val < 0)
	dev_warn(&client->dev,
	"invalid gpio-base in device tree\n");
	else
	pdata->gpio_base = *val;
	}

	val = of_get_property(node, "polarity", NULL);
	if (val)
	pdata->invert = *val;

	return pdata;
	}
	#else
	static struct pca953x_platform_data *
	pca953x_get_alt_pdata(struct i2c_client *client)
	{
	return NULL;
	}
	#endif

	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 ret;

	chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
	if (chip == NULL)
	return -ENOMEM;

	pdata = client->dev.platform_data;
	if (pdata == NULL) {
	pdata = pca953x_get_alt_pdata(client);
	/*
	* Unlike normal platform_data, this is allocated
	* dynamically and must be freed in the driver
	*/
	chip->dyn_pdata = pdata;
	}

	if (pdata == NULL) {
	dev_dbg(&client->dev, "no platform data\n");
	ret = -EINVAL;
	goto out_failed;
	}

	chip->client = client;

	chip->gpio_start = pdata->gpio_base;

	chip->names = pdata->names;

	/* initialize cached registers from their original values.
	* we can't share this chip with another i2c master.
	*/
	pca953x_setup_gpio(chip, id->driver_data & PCA953X_GPIOS);

	ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
	if (ret)
	goto out_failed;

	ret = pca953x_read_reg(chip, PCA953X_DIRECTION, &chip->reg_direction);
	if (ret)
	goto out_failed;

	/* set platform specific polarity inversion */
	ret = pca953x_write_reg(chip, PCA953X_INVERT, pdata->invert);
	if (ret)
	goto out_failed;

	ret = pca953x_irq_setup(chip, id);
	if (ret)
	goto out_failed;

	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:
	pca953x_irq_teardown(chip);
	kfree(chip->dyn_pdata);
	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->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->dyn_pdata);
	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");