/*

   *  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
  ");

  		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
  ");

  		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
  ",

  			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
  ",
  				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
  ");
  
  	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!

   */

  static 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
  ",
  				 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

  static void

  pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)

  {

  	*gpio_base = -1;

  }
  #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);

  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;

  	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)

  		ret = device_pca953x_init(chip, invert);

  	else

  		ret = device_pca957x_init(chip, invert);
  	if (ret)

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