/*

   *  PCA953x 4/8/16/24/40 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/acpi.h>

  #include <linux/gpio/driver.h>

  #include <linux/gpio/consumer.h>

  #include <linux/i2c.h>

  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/of_platform.h>

  #include <linux/platform_data/pca953x.h>

  #include <linux/regulator/consumer.h>

  #include <linux/reset.h>

  #include <linux/slab.h>

  #include <asm/unaligned.h>

  #define PCA953X_INPUT		0x00
  #define PCA953X_OUTPUT		0x01
  #define PCA953X_INVERT		0x02
  #define PCA953X_DIRECTION	0x03

  #define REG_ADDR_AI		0x80

  #define PCA957X_IN		0x00
  #define PCA957X_INVRT		0x01
  #define PCA957X_BKEN		0x02
  #define PCA957X_PUPD		0x03
  #define PCA957X_CFG		0x04
  #define PCA957X_OUT		0x05
  #define PCA957X_MSK		0x06
  #define PCA957X_INTS		0x07

  #define PCAL953X_OUT_STRENGTH	0x20

  #define PCAL953X_IN_LATCH	0x22

  #define PCAL953X_PULL_EN	0x23
  #define PCAL953X_PULL_SEL	0x24

  #define PCAL953X_INT_MASK	0x25
  #define PCAL953X_INT_STAT	0x26

  #define PCAL953X_OUT_CONF	0x27

  #define PCAL6524_INT_EDGE	0x28
  #define PCAL6524_INT_CLR	0x2a
  #define PCAL6524_IN_STATUS	0x2b
  #define PCAL6524_OUT_INDCONF	0x2c
  #define PCAL6524_DEBOUNCE	0x2d

  #define PCA_GPIO_MASK		0x00FF

  
  #define PCAL_GPIO_MASK		0x1f
  #define PCAL_PINCTRL_MASK	0xe0

  #define PCA_INT			0x0100

  #define PCA_PCAL		0x0200

  #define PCA_LATCH_INT (PCA_PCAL | PCA_INT)

  #define PCA953X_TYPE		0x1000
  #define PCA957X_TYPE		0x2000

  #define PCA_TYPE_MASK		0xF000
  
  #define PCA_CHIP_TYPE(x)	((x) & PCA_TYPE_MASK)

  static const struct i2c_device_id pca953x_id[] = {

  	{ "pca9505", 40 | PCA953X_TYPE | PCA_INT, },

  	{ "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, },

  	{ "pca9698", 40 | PCA953X_TYPE, },

  	{ "pcal6524", 24 | PCA953X_TYPE | PCA_INT | PCA_PCAL, },

  	{ "pcal9555a", 16 | PCA953X_TYPE | PCA_INT | PCA_PCAL, },

  	{ "max7310", 8  | PCA953X_TYPE, },
  	{ "max7312", 16 | PCA953X_TYPE | PCA_INT, },
  	{ "max7313", 16 | PCA953X_TYPE | PCA_INT, },
  	{ "max7315", 8  | PCA953X_TYPE | PCA_INT, },

  	{ "max7318", 16 | PCA953X_TYPE | PCA_INT, },

  	{ "pca6107", 8  | PCA953X_TYPE | PCA_INT, },
  	{ "tca6408", 8  | PCA953X_TYPE | PCA_INT, },
  	{ "tca6416", 16 | PCA953X_TYPE | PCA_INT, },

  	{ "tca6424", 24 | PCA953X_TYPE | PCA_INT, },

  	{ "tca9539", 16 | PCA953X_TYPE | PCA_INT, },

  	{ "tca9554", 8  | PCA953X_TYPE | PCA_INT, },

  	{ "xra1202", 8  | PCA953X_TYPE },

  	{ }

  };

  MODULE_DEVICE_TABLE(i2c, pca953x_id);

  static const struct acpi_device_id pca953x_acpi_ids[] = {

  	{ "INT3491", 16 | PCA953X_TYPE | PCA_INT | PCA_PCAL, },

  	{ }
  };
  MODULE_DEVICE_TABLE(acpi, pca953x_acpi_ids);

  #define MAX_BANK 5
  #define BANK_SZ 8

  #define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)

  struct pca953x_reg_config {
  	int direction;
  	int output;
  	int input;
  };
  
  static const struct pca953x_reg_config pca953x_regs = {
  	.direction = PCA953X_DIRECTION,
  	.output = PCA953X_OUTPUT,
  	.input = PCA953X_INPUT,
  };
  
  static const struct pca953x_reg_config pca957x_regs = {
  	.direction = PCA957X_CFG,
  	.output = PCA957X_OUT,
  	.input = PCA957X_IN,
  };

  struct pca953x_chip {

  	unsigned gpio_start;

  	u8 reg_output[MAX_BANK];
  	u8 reg_direction[MAX_BANK];

  	struct mutex i2c_lock;

  #ifdef CONFIG_GPIO_PCA953X_IRQ
  	struct mutex irq_lock;

  	u8 irq_mask[MAX_BANK];
  	u8 irq_stat[MAX_BANK];
  	u8 irq_trig_raise[MAX_BANK];
  	u8 irq_trig_fall[MAX_BANK];

  #endif

  	struct i2c_client *client;
  	struct gpio_chip gpio_chip;

  	const char *const *names;

  	unsigned long driver_data;

  	struct regulator *regulator;

  
  	const struct pca953x_reg_config *regs;

  
  	int (*write_regs)(struct pca953x_chip *, int, u8 *);

  	int (*read_regs)(struct pca953x_chip *, int, u8 *);

  };

  static int pca953x_read_single(struct pca953x_chip *chip, int reg, u32 *val,
  				int off)
  {
  	int ret;
  	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
  	int offset = off / BANK_SZ;
  
  	ret = i2c_smbus_read_byte_data(chip->client,
  				(reg << bank_shift) + offset);
  	*val = ret;
  
  	if (ret < 0) {
  		dev_err(&chip->client->dev, "failed reading register
  ");
  		return ret;
  	}
  
  	return 0;
  }
  
  static int pca953x_write_single(struct pca953x_chip *chip, int reg, u32 val,
  				int off)
  {

  	int ret;

  	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);
  	int offset = off / BANK_SZ;
  
  	ret = i2c_smbus_write_byte_data(chip->client,
  					(reg << bank_shift) + offset, val);
  
  	if (ret < 0) {
  		dev_err(&chip->client->dev, "failed writing register
  ");
  		return ret;
  	}
  
  	return 0;
  }

  static int pca953x_write_regs_8(struct pca953x_chip *chip, int reg, u8 *val)

  {

  	return i2c_smbus_write_byte_data(chip->client, reg, *val);
  }

  static int pca953x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
  {

  	u16 word = get_unaligned((u16 *)val);

  	return i2c_smbus_write_word_data(chip->client, reg << 1, word);

  }
  
  static int pca957x_write_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int ret;
  
  	ret = i2c_smbus_write_byte_data(chip->client, reg << 1, val[0]);
  	if (ret < 0)
  		return ret;
  
  	return i2c_smbus_write_byte_data(chip->client, (reg << 1) + 1, val[1]);
  }

  static int pca953x_write_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);

  	int addr = (reg & PCAL_GPIO_MASK) << bank_shift;
  	int pinctrl = (reg & PCAL_PINCTRL_MASK) << 1;

  
  	return i2c_smbus_write_i2c_block_data(chip->client,

  					      pinctrl | addr | REG_ADDR_AI,

  					      NBANK(chip), val);
  }
  
  static int pca953x_write_regs(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int ret = 0;
  
  	ret = chip->write_regs(chip, reg, val);

  	if (ret < 0) {
  		dev_err(&chip->client->dev, "failed writing register
  ");

  		return ret;

  	}
  
  	return 0;

  }

  static int pca953x_read_regs_8(struct pca953x_chip *chip, int reg, u8 *val)

  {
  	int ret;

  	ret = i2c_smbus_read_byte_data(chip->client, reg);
  	*val = ret;

  	return ret;
  }
  
  static int pca953x_read_regs_16(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int ret;
  
  	ret = i2c_smbus_read_word_data(chip->client, reg << 1);

  	put_unaligned(ret, (u16 *)val);

  
  	return ret;
  }
  
  static int pca953x_read_regs_24(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);

  	int addr = (reg & PCAL_GPIO_MASK) << bank_shift;
  	int pinctrl = (reg & PCAL_PINCTRL_MASK) << 1;

  
  	return i2c_smbus_read_i2c_block_data(chip->client,

  					     pinctrl | addr | REG_ADDR_AI,

  					     NBANK(chip), val);
  }
  
  static int pca953x_read_regs(struct pca953x_chip *chip, int reg, u8 *val)
  {
  	int ret;
  
  	ret = chip->read_regs(chip, reg, val);

  	if (ret < 0) {
  		dev_err(&chip->client->dev, "failed reading register
  ");

  		return ret;

  	}

  	return 0;
  }

  static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)

  {

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	u8 reg_val;

  	int ret;

  	mutex_lock(&chip->i2c_lock);

  	reg_val = chip->reg_direction[off / BANK_SZ] | (1u << (off % BANK_SZ));

  	ret = pca953x_write_single(chip, chip->regs->direction, reg_val, off);

  	if (ret)

  		goto exit;

  	chip->reg_direction[off / BANK_SZ] = reg_val;

  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 = gpiochip_get_data(gc);

  	u8 reg_val;

  	int ret;

  	mutex_lock(&chip->i2c_lock);

  	/* set output level */
  	if (val)

  		reg_val = chip->reg_output[off / BANK_SZ]
  			| (1u << (off % BANK_SZ));

  	else

  		reg_val = chip->reg_output[off / BANK_SZ]
  			& ~(1u << (off % BANK_SZ));

  	ret = pca953x_write_single(chip, chip->regs->output, reg_val, off);

  	if (ret)

  		goto exit;

  	chip->reg_output[off / BANK_SZ] = reg_val;

  
  	/* then direction */

  	reg_val = chip->reg_direction[off / BANK_SZ] & ~(1u << (off % BANK_SZ));

  	ret = pca953x_write_single(chip, chip->regs->direction, reg_val, off);

  	if (ret)

  		goto exit;

  	chip->reg_direction[off / BANK_SZ] = reg_val;

  exit:
  	mutex_unlock(&chip->i2c_lock);
  	return ret;

  }

  static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)

  {

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	u32 reg_val;

  	int ret;

  	mutex_lock(&chip->i2c_lock);

  	ret = pca953x_read_single(chip, chip->regs->input, &reg_val, off);

  	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 % BANK_SZ))) ? 1 : 0;

  }

  static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)

  {

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	u8 reg_val;

  	int ret;

  	mutex_lock(&chip->i2c_lock);

  	if (val)

  		reg_val = chip->reg_output[off / BANK_SZ]
  			| (1u << (off % BANK_SZ));

  	else

  		reg_val = chip->reg_output[off / BANK_SZ]
  			& ~(1u << (off % BANK_SZ));

  	ret = pca953x_write_single(chip, chip->regs->output, reg_val, off);

  	if (ret)

  		goto exit;

  	chip->reg_output[off / BANK_SZ] = reg_val;

  exit:
  	mutex_unlock(&chip->i2c_lock);

  }

  static int pca953x_gpio_get_direction(struct gpio_chip *gc, unsigned off)
  {
  	struct pca953x_chip *chip = gpiochip_get_data(gc);
  	u32 reg_val;
  	int ret;
  
  	mutex_lock(&chip->i2c_lock);
  	ret = pca953x_read_single(chip, chip->regs->direction, &reg_val, off);
  	mutex_unlock(&chip->i2c_lock);
  	if (ret < 0)
  		return ret;
  
  	return !!(reg_val & (1u << (off % BANK_SZ)));
  }

  static void pca953x_gpio_set_multiple(struct gpio_chip *gc,

  				      unsigned long *mask, unsigned long *bits)

  {

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	unsigned int bank_mask, bank_val;
  	int bank_shift, bank;

  	u8 reg_val[MAX_BANK];

  	int ret;

  
  	bank_shift = fls((chip->gpio_chip.ngpio - 1) / BANK_SZ);

  	mutex_lock(&chip->i2c_lock);

  	memcpy(reg_val, chip->reg_output, NBANK(chip));

  	for (bank = 0; bank < NBANK(chip); bank++) {
  		bank_mask = mask[bank / sizeof(*mask)] >>
  			   ((bank % sizeof(*mask)) * 8);
  		if (bank_mask) {
  			bank_val = bits[bank / sizeof(*bits)] >>
  				  ((bank % sizeof(*bits)) * 8);

  			bank_val &= bank_mask;

  			reg_val[bank] = (reg_val[bank] & ~bank_mask) | bank_val;

  		}
  	}

  	ret = i2c_smbus_write_i2c_block_data(chip->client,
  					     chip->regs->output << bank_shift,
  					     NBANK(chip), reg_val);

  	if (ret)
  		goto exit;
  
  	memcpy(chip->reg_output, reg_val, NBANK(chip));
  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->get_direction = pca953x_gpio_get_direction;

  	gc->set_multiple = pca953x_gpio_set_multiple;

  	gc->can_sleep = true;

  
  	gc->base = chip->gpio_start;

  	gc->ngpio = gpios;
  	gc->label = chip->client->name;

  	gc->parent = &chip->client->dev;

  	gc->owner = THIS_MODULE;

  	gc->names = chip->names;

  }

  #ifdef CONFIG_GPIO_PCA953X_IRQ

  static void pca953x_irq_mask(struct irq_data *d)

  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	chip->irq_mask[d->hwirq / BANK_SZ] &= ~(1 << (d->hwirq % BANK_SZ));

  }

  static void pca953x_irq_unmask(struct irq_data *d)

  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	chip->irq_mask[d->hwirq / BANK_SZ] |= 1 << (d->hwirq % BANK_SZ);

  }

  static void pca953x_irq_bus_lock(struct irq_data *d)

  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  
  	mutex_lock(&chip->irq_lock);
  }

  static void pca953x_irq_bus_sync_unlock(struct irq_data *d)

  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	u8 new_irqs;
  	int level, i;

  	u8 invert_irq_mask[MAX_BANK];
  
  	if (chip->driver_data & PCA_PCAL) {
  		/* Enable latch on interrupt-enabled inputs */
  		pca953x_write_regs(chip, PCAL953X_IN_LATCH, chip->irq_mask);
  
  		for (i = 0; i < NBANK(chip); i++)
  			invert_irq_mask[i] = ~chip->irq_mask[i];
  
  		/* Unmask enabled interrupts */
  		pca953x_write_regs(chip, PCAL953X_INT_MASK, invert_irq_mask);
  	}

  
  	/* Look for any newly setup interrupt */

  	for (i = 0; i < NBANK(chip); i++) {
  		new_irqs = chip->irq_trig_fall[i] | chip->irq_trig_raise[i];
  		new_irqs &= ~chip->reg_direction[i];
  
  		while (new_irqs) {
  			level = __ffs(new_irqs);
  			pca953x_gpio_direction_input(&chip->gpio_chip,
  							level + (BANK_SZ * i));
  			new_irqs &= ~(1 << level);
  		}

  	}

  
  	mutex_unlock(&chip->irq_lock);
  }

  static int pca953x_irq_set_type(struct irq_data *d, unsigned int type)

  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);

  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	int bank_nb = d->hwirq / BANK_SZ;
  	u8 mask = 1 << (d->hwirq % BANK_SZ);

  
  	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[bank_nb] |= mask;

  	else

  		chip->irq_trig_fall[bank_nb] &= ~mask;

  
  	if (type & IRQ_TYPE_EDGE_RISING)

  		chip->irq_trig_raise[bank_nb] |= mask;

  	else

  		chip->irq_trig_raise[bank_nb] &= ~mask;

  	return 0;

  }

  static void pca953x_irq_shutdown(struct irq_data *d)
  {

  	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
  	struct pca953x_chip *chip = gpiochip_get_data(gc);

  	u8 mask = 1 << (d->hwirq % BANK_SZ);
  
  	chip->irq_trig_raise[d->hwirq / BANK_SZ] &= ~mask;
  	chip->irq_trig_fall[d->hwirq / BANK_SZ] &= ~mask;
  }

  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,

  	.irq_shutdown		= pca953x_irq_shutdown,

  };

  static bool pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending)

  {

  	u8 cur_stat[MAX_BANK];
  	u8 old_stat[MAX_BANK];

  	bool pending_seen = false;
  	bool trigger_seen = false;
  	u8 trigger[MAX_BANK];

  	int ret, i;

  	if (chip->driver_data & PCA_PCAL) {
  		/* Read the current interrupt status from the device */
  		ret = pca953x_read_regs(chip, PCAL953X_INT_STAT, trigger);
  		if (ret)
  			return false;
  
  		/* Check latched inputs and clear interrupt status */
  		ret = pca953x_read_regs(chip, PCA953X_INPUT, cur_stat);
  		if (ret)
  			return false;
  
  		for (i = 0; i < NBANK(chip); i++) {
  			/* Apply filter for rising/falling edge selection */
  			pending[i] = (~cur_stat[i] & chip->irq_trig_fall[i]) |
  				(cur_stat[i] & chip->irq_trig_raise[i]);
  			pending[i] &= trigger[i];
  			if (pending[i])
  				pending_seen = true;
  		}
  
  		return pending_seen;
  	}

  	ret = pca953x_read_regs(chip, chip->regs->input, cur_stat);

  	if (ret)

  		return false;

  
  	/* Remove output pins from the equation */

  	for (i = 0; i < NBANK(chip); i++)
  		cur_stat[i] &= chip->reg_direction[i];

  	memcpy(old_stat, chip->irq_stat, NBANK(chip));

  	for (i = 0; i < NBANK(chip); i++) {
  		trigger[i] = (cur_stat[i] ^ old_stat[i]) & chip->irq_mask[i];

  		if (trigger[i])
  			trigger_seen = true;

  	}

  	if (!trigger_seen)
  		return false;

  	memcpy(chip->irq_stat, cur_stat, NBANK(chip));

  	for (i = 0; i < NBANK(chip); i++) {
  		pending[i] = (old_stat[i] & chip->irq_trig_fall[i]) |
  			(cur_stat[i] & chip->irq_trig_raise[i]);
  		pending[i] &= trigger[i];

  		if (pending[i])
  			pending_seen = true;

  	}

  	return pending_seen;

  }
  
  static irqreturn_t pca953x_irq_handler(int irq, void *devid)
  {
  	struct pca953x_chip *chip = devid;

  	u8 pending[MAX_BANK];
  	u8 level;

  	unsigned nhandled = 0;

  	int i;

  	if (!pca953x_irq_pending(chip, pending))

  		return IRQ_NONE;

  	for (i = 0; i < NBANK(chip); i++) {
  		while (pending[i]) {
  			level = __ffs(pending[i]);

  			handle_nested_irq(irq_find_mapping(chip->gpio_chip.irq.domain,

  							level + (BANK_SZ * i)));
  			pending[i] &= ~(1 << level);

  			nhandled++;

  		}
  	}

  	return (nhandled > 0) ? IRQ_HANDLED : IRQ_NONE;

  }
  
  static int pca953x_irq_setup(struct pca953x_chip *chip,

  			     int irq_base)

  {
  	struct i2c_client *client = chip->client;

  	int ret, i;

  	if (client->irq && irq_base != -1

  			&& (chip->driver_data & PCA_INT)) {

  		ret = pca953x_read_regs(chip,
  					chip->regs->input, chip->irq_stat);

  		if (ret)

  			return ret;

  
  		/*
  		 * There is no way to know which GPIO line generated the
  		 * interrupt.  We have to rely on the previous read for
  		 * this purpose.
  		 */

  		for (i = 0; i < NBANK(chip); i++)
  			chip->irq_stat[i] &= chip->reg_direction[i];

  		mutex_init(&chip->irq_lock);

  		ret = devm_request_threaded_irq(&client->dev,
  					client->irq,

  					   NULL,
  					   pca953x_irq_handler,

  					   IRQF_TRIGGER_LOW | IRQF_ONESHOT |
  						   IRQF_SHARED,

  					   dev_name(&client->dev), chip);
  		if (ret) {
  			dev_err(&client->dev, "failed to request irq %d
  ",
  				client->irq);

  			return ret;

  		}

  		ret =  gpiochip_irqchip_add_nested(&chip->gpio_chip,
  						   &pca953x_irq_chip,
  						   irq_base,
  						   handle_simple_irq,
  						   IRQ_TYPE_NONE);

  		if (ret) {
  			dev_err(&client->dev,
  				"could not connect irqchip to gpiochip
  ");
  			return ret;
  		}

  		gpiochip_set_nested_irqchip(&chip->gpio_chip,
  					    &pca953x_irq_chip,
  					    client->irq);

  	}
  
  	return 0;

  }

  #else /* CONFIG_GPIO_PCA953X_IRQ */
  static int pca953x_irq_setup(struct pca953x_chip *chip,

  			     int irq_base)

  {
  	struct i2c_client *client = chip->client;

  	if (client->irq && irq_base != -1 && (chip->driver_data & PCA_INT))

  		dev_warn(&client->dev, "interrupt support not compiled in
  ");
  
  	return 0;
  }

  #endif

  static int device_pca953x_init(struct pca953x_chip *chip, u32 invert)

  {
  	int ret;

  	u8 val[MAX_BANK];

  	chip->regs = &pca953x_regs;
  
  	ret = pca953x_read_regs(chip, chip->regs->output, chip->reg_output);

  	if (ret)
  		goto out;

  	ret = pca953x_read_regs(chip, chip->regs->direction,
  				chip->reg_direction);

  	if (ret)
  		goto out;
  
  	/* set platform specific polarity inversion */

  	if (invert)
  		memset(val, 0xFF, NBANK(chip));
  	else
  		memset(val, 0, NBANK(chip));
  
  	ret = pca953x_write_regs(chip, PCA953X_INVERT, val);

  out:
  	return ret;
  }

  static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)

  {
  	int ret;

  	u8 val[MAX_BANK];

  	chip->regs = &pca957x_regs;
  
  	ret = pca953x_read_regs(chip, chip->regs->output, chip->reg_output);

  	if (ret)
  		goto out;

  	ret = pca953x_read_regs(chip, chip->regs->direction,
  				chip->reg_direction);

  	if (ret)
  		goto out;
  
  	/* set platform specific polarity inversion */

  	if (invert)
  		memset(val, 0xFF, NBANK(chip));
  	else
  		memset(val, 0, NBANK(chip));

  	ret = pca953x_write_regs(chip, PCA957X_INVRT, val);
  	if (ret)
  		goto out;

  	/* To enable register 6, 7 to control pull up and pull down */

  	memset(val, 0x02, NBANK(chip));

  	ret = pca953x_write_regs(chip, PCA957X_BKEN, val);
  	if (ret)
  		goto out;

  
  	return 0;
  out:
  	return ret;
  }

  static const struct of_device_id pca953x_dt_ids[];

  static int pca953x_probe(struct i2c_client *client,

  				   const struct i2c_device_id *i2c_id)

  {

  	struct pca953x_platform_data *pdata;
  	struct pca953x_chip *chip;

  	int irq_base = 0;

  	int ret;

  	u32 invert = 0;

  	struct regulator *reg;

  	chip = devm_kzalloc(&client->dev,
  			sizeof(struct pca953x_chip), GFP_KERNEL);

  	if (chip == NULL)
  		return -ENOMEM;

  	pdata = dev_get_platdata(&client->dev);

  	if (pdata) {
  		irq_base = pdata->irq_base;
  		chip->gpio_start = pdata->gpio_base;
  		invert = pdata->invert;
  		chip->names = pdata->names;
  	} else {

  		struct gpio_desc *reset_gpio;

  		chip->gpio_start = -1;
  		irq_base = 0;

  		/*
  		 * See if we need to de-assert a reset pin.
  		 *
  		 * There is no known ACPI-enabled platforms that are
  		 * using "reset" GPIO. Otherwise any of those platform
  		 * must use _DSD method with corresponding property.
  		 */

  		reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
  						     GPIOD_OUT_LOW);
  		if (IS_ERR(reset_gpio))
  			return PTR_ERR(reset_gpio);

  	}

  
  	chip->client = client;

  	reg = devm_regulator_get(&client->dev, "vcc");
  	if (IS_ERR(reg)) {
  		ret = PTR_ERR(reg);
  		if (ret != -EPROBE_DEFER)
  			dev_err(&client->dev, "reg get err: %d
  ", ret);
  		return ret;
  	}
  	ret = regulator_enable(reg);
  	if (ret) {
  		dev_err(&client->dev, "reg en err: %d
  ", ret);
  		return ret;
  	}
  	chip->regulator = reg;

  	if (i2c_id) {
  		chip->driver_data = i2c_id->driver_data;

  	} else {

  		const struct acpi_device_id *acpi_id;

  		struct device *dev = &client->dev;

  		chip->driver_data = (uintptr_t)of_device_get_match_data(dev);
  		if (!chip->driver_data) {
  			acpi_id = acpi_match_device(pca953x_acpi_ids, dev);

  			if (!acpi_id) {

  				ret = -ENODEV;
  				goto err_exit;
  			}

  			chip->driver_data = acpi_id->driver_data;

  		}

  	}

  	mutex_init(&chip->i2c_lock);

  	/*
  	 * In case we have an i2c-mux controlled by a GPIO provided by an
  	 * expander using the same driver higher on the device tree, read the
  	 * i2c adapter nesting depth and use the retrieved value as lockdep
  	 * subclass for chip->i2c_lock.
  	 *
  	 * REVISIT: This solution is not complete. It protects us from lockdep
  	 * false positives when the expander controlling the i2c-mux is on
  	 * a different level on the device tree, but not when it's on the same
  	 * level on a different branch (in which case the subclass number
  	 * would be the same).
  	 *
  	 * TODO: Once a correct solution is developed, a similar fix should be
  	 * applied to all other i2c-controlled GPIO expanders (and potentially
  	 * regmap-i2c).
  	 */

  	lockdep_set_subclass(&chip->i2c_lock,
  			     i2c_adapter_depth(client->adapter));

  	ret = device_reset(&client->dev);

  	if (ret == -EPROBE_DEFER)

  		return -EPROBE_DEFER;

  	/* initialize cached registers from their original values.
  	 * we can't share this chip with another i2c master.
  	 */

  	pca953x_setup_gpio(chip, chip->driver_data & PCA_GPIO_MASK);

  	if (chip->gpio_chip.ngpio <= 8) {
  		chip->write_regs = pca953x_write_regs_8;

  		chip->read_regs = pca953x_read_regs_8;

  	} else if (chip->gpio_chip.ngpio >= 24) {
  		chip->write_regs = pca953x_write_regs_24;

  		chip->read_regs = pca953x_read_regs_24;

  	} else {
  		if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)
  			chip->write_regs = pca953x_write_regs_16;
  		else
  			chip->write_regs = pca957x_write_regs_16;

  		chip->read_regs = pca953x_read_regs_16;

  	}

  	if (PCA_CHIP_TYPE(chip->driver_data) == PCA953X_TYPE)

  		ret = device_pca953x_init(chip, invert);

  	else

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

  		goto err_exit;

  	ret = devm_gpiochip_add_data(&client->dev, &chip->gpio_chip, chip);

  	if (ret)

  		goto err_exit;

  	ret = pca953x_irq_setup(chip, irq_base);

  	if (ret)

  		goto err_exit;

  	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;

  
  err_exit:
  	regulator_disable(chip->regulator);
  	return ret;

  }

  static int pca953x_remove(struct i2c_client *client)

  {

  	struct pca953x_platform_data *pdata = dev_get_platdata(&client->dev);

  	struct pca953x_chip *chip = i2c_get_clientdata(client);

  	int ret;

  	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);

  	} else {
  		ret = 0;

  	}

  	regulator_disable(chip->regulator);
  
  	return ret;

  }

  /* convenience to stop overlong match-table lines */
  #define OF_953X(__nrgpio, __int) (void *)(__nrgpio | PCA953X_TYPE | __int)
  #define OF_957X(__nrgpio, __int) (void *)(__nrgpio | PCA957X_TYPE | __int)

  static const struct of_device_id pca953x_dt_ids[] = {

  	{ .compatible = "nxp,pca9505", .data = OF_953X(40, PCA_INT), },
  	{ .compatible = "nxp,pca9534", .data = OF_953X( 8, PCA_INT), },
  	{ .compatible = "nxp,pca9535", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "nxp,pca9536", .data = OF_953X( 4, 0), },
  	{ .compatible = "nxp,pca9537", .data = OF_953X( 4, PCA_INT), },
  	{ .compatible = "nxp,pca9538", .data = OF_953X( 8, PCA_INT), },
  	{ .compatible = "nxp,pca9539", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "nxp,pca9554", .data = OF_953X( 8, PCA_INT), },
  	{ .compatible = "nxp,pca9555", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "nxp,pca9556", .data = OF_953X( 8, 0), },
  	{ .compatible = "nxp,pca9557", .data = OF_953X( 8, 0), },
  	{ .compatible = "nxp,pca9574", .data = OF_957X( 8, PCA_INT), },
  	{ .compatible = "nxp,pca9575", .data = OF_957X(16, PCA_INT), },
  	{ .compatible = "nxp,pca9698", .data = OF_953X(40, 0), },

  	{ .compatible = "nxp,pcal6524", .data = OF_953X(24, PCA_LATCH_INT), },
  	{ .compatible = "nxp,pcal9555a", .data = OF_953X(16, PCA_LATCH_INT), },

  	{ .compatible = "maxim,max7310", .data = OF_953X( 8, 0), },
  	{ .compatible = "maxim,max7312", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "maxim,max7313", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "maxim,max7315", .data = OF_953X( 8, PCA_INT), },

  	{ .compatible = "maxim,max7318", .data = OF_953X(16, PCA_INT), },

  
  	{ .compatible = "ti,pca6107", .data = OF_953X( 8, PCA_INT), },

  	{ .compatible = "ti,pca9536", .data = OF_953X( 4, 0), },

  	{ .compatible = "ti,tca6408", .data = OF_953X( 8, PCA_INT), },
  	{ .compatible = "ti,tca6416", .data = OF_953X(16, PCA_INT), },
  	{ .compatible = "ti,tca6424", .data = OF_953X(24, PCA_INT), },

  	{ .compatible = "onnn,pca9654", .data = OF_953X( 8, PCA_INT), },

  
  	{ .compatible = "exar,xra1202", .data = OF_953X( 8, 0), },

  	{ }
  };
  
  MODULE_DEVICE_TABLE(of, pca953x_dt_ids);

  static struct i2c_driver pca953x_driver = {

  	.driver = {

  		.name	= "pca953x",

  		.of_match_table = pca953x_dt_ids,

  		.acpi_match_table = ACPI_PTR(pca953x_acpi_ids),

  	},

  	.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");