/*
   * GPIO Chip driver for Analog Devices

   * ADP5588/ADP5587 I/O Expander and QWERTY Keypad Controller

   *

   * Copyright 2009-2010 Analog Devices Inc.

   *
   * Licensed under the GPL-2 or later.
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>

  #include <linux/slab.h>

  #include <linux/init.h>
  #include <linux/i2c.h>
  #include <linux/gpio.h>

  #include <linux/interrupt.h>
  #include <linux/irq.h>

  
  #include <linux/i2c/adp5588.h>

  #define DRV_NAME	"adp5588-gpio"
  
  /*
   * Early pre 4.0 Silicon required to delay readout by at least 25ms,
   * since the Event Counter Register updated 25ms after the interrupt
   * asserted.
   */
  #define WA_DELAYED_READOUT_REVID(rev)	((rev) < 4)

  
  struct adp5588_gpio {
  	struct i2c_client *client;
  	struct gpio_chip gpio_chip;
  	struct mutex lock;	/* protect cached dir, dat_out */

  	/* protect serialized access to the interrupt controller bus */
  	struct mutex irq_lock;

  	unsigned gpio_start;

  	unsigned irq_base;

  	uint8_t dat_out[3];
  	uint8_t dir[3];

  	uint8_t int_lvl[3];
  	uint8_t int_en[3];
  	uint8_t irq_mask[3];
  	uint8_t irq_stat[3];

  };
  
  static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
  {
  	int ret = i2c_smbus_read_byte_data(client, reg);
  
  	if (ret < 0)
  		dev_err(&client->dev, "Read Error
  ");
  
  	return ret;
  }
  
  static int adp5588_gpio_write(struct i2c_client *client, u8 reg, u8 val)
  {
  	int ret = i2c_smbus_write_byte_data(client, reg, val);
  
  	if (ret < 0)
  		dev_err(&client->dev, "Write Error
  ");
  
  	return ret;
  }
  
  static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off)
  {

  	struct adp5588_gpio *dev = gpiochip_get_data(chip);

  	unsigned bank = ADP5588_BANK(off);
  	unsigned bit = ADP5588_BIT(off);
  	int val;

  	mutex_lock(&dev->lock);
  
  	if (dev->dir[bank] & bit)
  		val = dev->dat_out[bank];
  	else
  		val = adp5588_gpio_read(dev->client, GPIO_DAT_STAT1 + bank);
  
  	mutex_unlock(&dev->lock);
  
  	return !!(val & bit);

  }
  
  static void adp5588_gpio_set_value(struct gpio_chip *chip,
  				   unsigned off, int val)
  {
  	unsigned bank, bit;

  	struct adp5588_gpio *dev = gpiochip_get_data(chip);

  	bank = ADP5588_BANK(off);
  	bit = ADP5588_BIT(off);

  
  	mutex_lock(&dev->lock);
  	if (val)
  		dev->dat_out[bank] |= bit;
  	else
  		dev->dat_out[bank] &= ~bit;
  
  	adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
  			   dev->dat_out[bank]);
  	mutex_unlock(&dev->lock);
  }
  
  static int adp5588_gpio_direction_input(struct gpio_chip *chip, unsigned off)
  {
  	int ret;
  	unsigned bank;

  	struct adp5588_gpio *dev = gpiochip_get_data(chip);

  	bank = ADP5588_BANK(off);

  
  	mutex_lock(&dev->lock);

  	dev->dir[bank] &= ~ADP5588_BIT(off);

  	ret = adp5588_gpio_write(dev->client, GPIO_DIR1 + bank, dev->dir[bank]);
  	mutex_unlock(&dev->lock);
  
  	return ret;
  }
  
  static int adp5588_gpio_direction_output(struct gpio_chip *chip,
  					 unsigned off, int val)
  {
  	int ret;
  	unsigned bank, bit;

  	struct adp5588_gpio *dev = gpiochip_get_data(chip);

  	bank = ADP5588_BANK(off);
  	bit = ADP5588_BIT(off);

  
  	mutex_lock(&dev->lock);
  	dev->dir[bank] |= bit;
  
  	if (val)
  		dev->dat_out[bank] |= bit;
  	else
  		dev->dat_out[bank] &= ~bit;
  
  	ret = adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
  				 dev->dat_out[bank]);
  	ret |= adp5588_gpio_write(dev->client, GPIO_DIR1 + bank,
  				 dev->dir[bank]);
  	mutex_unlock(&dev->lock);
  
  	return ret;
  }

  #ifdef CONFIG_GPIO_ADP5588_IRQ
  static int adp5588_gpio_to_irq(struct gpio_chip *chip, unsigned off)
  {

  	struct adp5588_gpio *dev = gpiochip_get_data(chip);

  	return dev->irq_base + off;
  }

  static void adp5588_irq_bus_lock(struct irq_data *d)

  {

  	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);

  	mutex_lock(&dev->irq_lock);
  }
  
   /*
    * genirq core code can issue chip->mask/unmask from atomic context.
    * This doesn't work for slow busses where an access needs to sleep.
    * bus_sync_unlock() is therefore called outside the atomic context,
    * syncs the current irq mask state with the slow external controller
    * and unlocks the bus.
    */

  static void adp5588_irq_bus_sync_unlock(struct irq_data *d)

  {

  	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);

  	int i;
  
  	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++)
  		if (dev->int_en[i] ^ dev->irq_mask[i]) {
  			dev->int_en[i] = dev->irq_mask[i];
  			adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
  					   dev->int_en[i]);
  		}
  
  	mutex_unlock(&dev->irq_lock);
  }

  static void adp5588_irq_mask(struct irq_data *d)

  {

  	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
  	unsigned gpio = d->irq - dev->irq_base;

  
  	dev->irq_mask[ADP5588_BANK(gpio)] &= ~ADP5588_BIT(gpio);
  }

  static void adp5588_irq_unmask(struct irq_data *d)

  {

  	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
  	unsigned gpio = d->irq - dev->irq_base;

  
  	dev->irq_mask[ADP5588_BANK(gpio)] |= ADP5588_BIT(gpio);
  }

  static int adp5588_irq_set_type(struct irq_data *d, unsigned int type)

  {

  	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
  	uint16_t gpio = d->irq - dev->irq_base;

  	unsigned bank, bit;
  
  	if ((type & IRQ_TYPE_EDGE_BOTH)) {
  		dev_err(&dev->client->dev, "irq %d: unsupported type %d
  ",

  			d->irq, type);

  		return -EINVAL;
  	}
  
  	bank = ADP5588_BANK(gpio);
  	bit = ADP5588_BIT(gpio);
  
  	if (type & IRQ_TYPE_LEVEL_HIGH)
  		dev->int_lvl[bank] |= bit;
  	else if (type & IRQ_TYPE_LEVEL_LOW)
  		dev->int_lvl[bank] &= ~bit;
  	else
  		return -EINVAL;
  
  	adp5588_gpio_direction_input(&dev->gpio_chip, gpio);
  	adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + bank,
  			   dev->int_lvl[bank]);
  
  	return 0;
  }
  
  static struct irq_chip adp5588_irq_chip = {
  	.name			= "adp5588",

  	.irq_mask		= adp5588_irq_mask,
  	.irq_unmask		= adp5588_irq_unmask,
  	.irq_bus_lock		= adp5588_irq_bus_lock,
  	.irq_bus_sync_unlock	= adp5588_irq_bus_sync_unlock,
  	.irq_set_type		= adp5588_irq_set_type,

  };
  
  static int adp5588_gpio_read_intstat(struct i2c_client *client, u8 *buf)
  {
  	int ret = i2c_smbus_read_i2c_block_data(client, GPIO_INT_STAT1, 3, buf);
  
  	if (ret < 0)
  		dev_err(&client->dev, "Read INT_STAT Error
  ");
  
  	return ret;
  }
  
  static irqreturn_t adp5588_irq_handler(int irq, void *devid)
  {
  	struct adp5588_gpio *dev = devid;
  	unsigned status, bank, bit, pending;
  	int ret;
  	status = adp5588_gpio_read(dev->client, INT_STAT);
  
  	if (status & ADP5588_GPI_INT) {
  		ret = adp5588_gpio_read_intstat(dev->client, dev->irq_stat);
  		if (ret < 0)
  			memset(dev->irq_stat, 0, ARRAY_SIZE(dev->irq_stat));

  		for (bank = 0, bit = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);

  			bank++, bit = 0) {
  			pending = dev->irq_stat[bank] & dev->irq_mask[bank];
  
  			while (pending) {
  				if (pending & (1 << bit)) {
  					handle_nested_irq(dev->irq_base +
  							  (bank << 3) + bit);
  					pending &= ~(1 << bit);
  
  				}
  				bit++;
  			}
  		}
  	}
  
  	adp5588_gpio_write(dev->client, INT_STAT, status); /* Status is W1C */
  
  	return IRQ_HANDLED;
  }
  
  static int adp5588_irq_setup(struct adp5588_gpio *dev)
  {
  	struct i2c_client *client = dev->client;

  	struct adp5588_gpio_platform_data *pdata =
  			dev_get_platdata(&client->dev);

  	unsigned gpio;
  	int ret;
  
  	adp5588_gpio_write(client, CFG, ADP5588_AUTO_INC);
  	adp5588_gpio_write(client, INT_STAT, -1); /* status is W1C */
  	adp5588_gpio_read_intstat(client, dev->irq_stat); /* read to clear */
  
  	dev->irq_base = pdata->irq_base;
  	mutex_init(&dev->irq_lock);
  
  	for (gpio = 0; gpio < dev->gpio_chip.ngpio; gpio++) {
  		int irq = gpio + dev->irq_base;

  		irq_set_chip_data(irq, dev);
  		irq_set_chip_and_handler(irq, &adp5588_irq_chip,

  					 handle_level_irq);

  		irq_set_nested_thread(irq, 1);

  		irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);

  	}
  
  	ret = request_threaded_irq(client->irq,
  				   NULL,
  				   adp5588_irq_handler,
  				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				   dev_name(&client->dev), dev);
  	if (ret) {
  		dev_err(&client->dev, "failed to request irq %d
  ",
  			client->irq);
  		goto out;
  	}
  
  	dev->gpio_chip.to_irq = adp5588_gpio_to_irq;
  	adp5588_gpio_write(client, CFG,
  		ADP5588_AUTO_INC | ADP5588_INT_CFG | ADP5588_GPI_INT);
  
  	return 0;
  
  out:
  	dev->irq_base = 0;
  	return ret;
  }
  
  static void adp5588_irq_teardown(struct adp5588_gpio *dev)
  {
  	if (dev->irq_base)
  		free_irq(dev->client->irq, dev);
  }
  
  #else
  static int adp5588_irq_setup(struct adp5588_gpio *dev)
  {
  	struct i2c_client *client = dev->client;
  	dev_warn(&client->dev, "interrupt support not compiled in
  ");
  
  	return 0;
  }
  
  static void adp5588_irq_teardown(struct adp5588_gpio *dev)
  {
  }
  #endif /* CONFIG_GPIO_ADP5588_IRQ */

  static int adp5588_gpio_probe(struct i2c_client *client,

  					const struct i2c_device_id *id)
  {

  	struct adp5588_gpio_platform_data *pdata =
  			dev_get_platdata(&client->dev);

  	struct adp5588_gpio *dev;
  	struct gpio_chip *gc;
  	int ret, i, revid;

  	if (!pdata) {

  		dev_err(&client->dev, "missing platform data
  ");
  		return -ENODEV;
  	}
  
  	if (!i2c_check_functionality(client->adapter,
  					I2C_FUNC_SMBUS_BYTE_DATA)) {
  		dev_err(&client->dev, "SMBUS Byte Data not Supported
  ");
  		return -EIO;
  	}

  	dev = devm_kzalloc(&client->dev, sizeof(*dev), GFP_KERNEL);

  	if (!dev)

  		return -ENOMEM;

  
  	dev->client = client;
  
  	gc = &dev->gpio_chip;
  	gc->direction_input = adp5588_gpio_direction_input;
  	gc->direction_output = adp5588_gpio_direction_output;
  	gc->get = adp5588_gpio_get_value;
  	gc->set = adp5588_gpio_set_value;

  	gc->can_sleep = true;

  
  	gc->base = pdata->gpio_start;

  	gc->ngpio = ADP5588_MAXGPIO;

  	gc->label = client->name;
  	gc->owner = THIS_MODULE;

  	gc->names = pdata->names;

  
  	mutex_init(&dev->lock);

  	ret = adp5588_gpio_read(dev->client, DEV_ID);
  	if (ret < 0)
  		goto err;
  
  	revid = ret & ADP5588_DEVICE_ID_MASK;

  	for (i = 0, ret = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {

  		dev->dat_out[i] = adp5588_gpio_read(client, GPIO_DAT_OUT1 + i);
  		dev->dir[i] = adp5588_gpio_read(client, GPIO_DIR1 + i);
  		ret |= adp5588_gpio_write(client, KP_GPIO1 + i, 0);
  		ret |= adp5588_gpio_write(client, GPIO_PULL1 + i,
  				(pdata->pullup_dis_mask >> (8 * i)) & 0xFF);

  		ret |= adp5588_gpio_write(client, GPIO_INT_EN1 + i, 0);

  		if (ret)
  			goto err;
  	}

  	if (pdata->irq_base) {
  		if (WA_DELAYED_READOUT_REVID(revid)) {
  			dev_warn(&client->dev, "GPIO int not supported
  ");
  		} else {
  			ret = adp5588_irq_setup(dev);
  			if (ret)
  				goto err;
  		}
  	}

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

  	if (ret)

  		goto err_irq;

  	dev_info(&client->dev, "IRQ Base: %d Rev.: %d
  ",
  			pdata->irq_base, revid);

  
  	if (pdata->setup) {
  		ret = pdata->setup(client, gc->base, gc->ngpio, pdata->context);
  		if (ret < 0)
  			dev_warn(&client->dev, "setup failed, %d
  ", ret);
  	}
  
  	i2c_set_clientdata(client, dev);

  	return 0;

  err_irq:
  	adp5588_irq_teardown(dev);

  err:

  	return ret;
  }

  static int adp5588_gpio_remove(struct i2c_client *client)

  {

  	struct adp5588_gpio_platform_data *pdata =
  			dev_get_platdata(&client->dev);

  	struct adp5588_gpio *dev = i2c_get_clientdata(client);
  	int ret;
  
  	if (pdata->teardown) {
  		ret = pdata->teardown(client,
  				      dev->gpio_chip.base, dev->gpio_chip.ngpio,
  				      pdata->context);
  		if (ret < 0) {
  			dev_err(&client->dev, "teardown failed %d
  ", ret);
  			return ret;
  		}
  	}

  	if (dev->irq_base)
  		free_irq(dev->client->irq, dev);

  	return 0;
  }
  
  static const struct i2c_device_id adp5588_gpio_id[] = {
  	{DRV_NAME, 0},
  	{}
  };
  
  MODULE_DEVICE_TABLE(i2c, adp5588_gpio_id);
  
  static struct i2c_driver adp5588_gpio_driver = {
  	.driver = {
  		   .name = DRV_NAME,
  		   },
  	.probe = adp5588_gpio_probe,

  	.remove = adp5588_gpio_remove,

  	.id_table = adp5588_gpio_id,
  };

  module_i2c_driver(adp5588_gpio_driver);

  
  MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
  MODULE_DESCRIPTION("GPIO ADP5588 Driver");
  MODULE_LICENSE("GPL");