/*

   * Retu/Tahvo MFD driver

   *
   * Copyright (C) 2004, 2005 Nokia Corporation
   *
   * Based on code written by Juha Yrjölä, David Weinehall and Mikko Ylinen.
   * Rewritten by Aaro Koskinen.
   *
   * This file is subject to the terms and conditions of the GNU General
   * Public License. See the file "COPYING" in the main directory of this
   * archive for more details.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   * GNU General Public License for more details.
   */
  
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/irq.h>

  #include <linux/slab.h>
  #include <linux/mutex.h>
  #include <linux/module.h>
  #include <linux/regmap.h>
  #include <linux/mfd/core.h>
  #include <linux/mfd/retu.h>
  #include <linux/interrupt.h>
  #include <linux/moduleparam.h>
  
  /* Registers */
  #define RETU_REG_ASICR		0x00		/* ASIC ID and revision */
  #define RETU_REG_ASICR_VILMA	(1 << 7)	/* Bit indicating Vilma */
  #define RETU_REG_IDR		0x01		/* Interrupt ID */

  #define RETU_REG_IMR		0x02		/* Interrupt mask (Retu) */
  #define TAHVO_REG_IMR		0x03		/* Interrupt mask (Tahvo) */

  
  /* Interrupt sources */
  #define RETU_INT_PWR		0		/* Power button */
  
  struct retu_dev {
  	struct regmap			*regmap;
  	struct device			*dev;
  	struct mutex			mutex;
  	struct regmap_irq_chip_data	*irq_data;
  };
  
  static struct resource retu_pwrbutton_res[] = {
  	{
  		.name	= "retu-pwrbutton",
  		.start	= RETU_INT_PWR,
  		.end	= RETU_INT_PWR,
  		.flags	= IORESOURCE_IRQ,
  	},
  };

  static const struct mfd_cell retu_devs[] = {

  	{
  		.name		= "retu-wdt"
  	},
  	{
  		.name		= "retu-pwrbutton",
  		.resources	= retu_pwrbutton_res,
  		.num_resources	= ARRAY_SIZE(retu_pwrbutton_res),
  	}
  };
  
  static struct regmap_irq retu_irqs[] = {
  	[RETU_INT_PWR] = {
  		.mask = 1 << RETU_INT_PWR,
  	}
  };
  
  static struct regmap_irq_chip retu_irq_chip = {
  	.name		= "RETU",
  	.irqs		= retu_irqs,
  	.num_irqs	= ARRAY_SIZE(retu_irqs),
  	.num_regs	= 1,
  	.status_base	= RETU_REG_IDR,
  	.mask_base	= RETU_REG_IMR,
  	.ack_base	= RETU_REG_IDR,
  };
  
  /* Retu device registered for the power off. */
  static struct retu_dev *retu_pm_power_off;

  static struct resource tahvo_usb_res[] = {
  	{
  		.name	= "tahvo-usb",
  		.start	= TAHVO_INT_VBUS,
  		.end	= TAHVO_INT_VBUS,
  		.flags	= IORESOURCE_IRQ,
  	},
  };

  static const struct mfd_cell tahvo_devs[] = {

  	{
  		.name		= "tahvo-usb",
  		.resources	= tahvo_usb_res,
  		.num_resources	= ARRAY_SIZE(tahvo_usb_res),
  	},
  };
  
  static struct regmap_irq tahvo_irqs[] = {
  	[TAHVO_INT_VBUS] = {
  		.mask = 1 << TAHVO_INT_VBUS,
  	}
  };
  
  static struct regmap_irq_chip tahvo_irq_chip = {
  	.name		= "TAHVO",
  	.irqs		= tahvo_irqs,
  	.num_irqs	= ARRAY_SIZE(tahvo_irqs),
  	.num_regs	= 1,
  	.status_base	= RETU_REG_IDR,
  	.mask_base	= TAHVO_REG_IMR,
  	.ack_base	= RETU_REG_IDR,
  };
  
  static const struct retu_data {
  	char			*chip_name;
  	char			*companion_name;
  	struct regmap_irq_chip	*irq_chip;

  	const struct mfd_cell	*children;

  	int			nchildren;
  } retu_data[] = {
  	[0] = {
  		.chip_name	= "Retu",
  		.companion_name	= "Vilma",
  		.irq_chip	= &retu_irq_chip,
  		.children	= retu_devs,
  		.nchildren	= ARRAY_SIZE(retu_devs),
  	},
  	[1] = {
  		.chip_name	= "Tahvo",
  		.companion_name	= "Betty",
  		.irq_chip	= &tahvo_irq_chip,
  		.children	= tahvo_devs,
  		.nchildren	= ARRAY_SIZE(tahvo_devs),
  	}
  };

  int retu_read(struct retu_dev *rdev, u8 reg)
  {
  	int ret;
  	int value;
  
  	mutex_lock(&rdev->mutex);
  	ret = regmap_read(rdev->regmap, reg, &value);
  	mutex_unlock(&rdev->mutex);
  
  	return ret ? ret : value;
  }
  EXPORT_SYMBOL_GPL(retu_read);
  
  int retu_write(struct retu_dev *rdev, u8 reg, u16 data)
  {
  	int ret;
  
  	mutex_lock(&rdev->mutex);
  	ret = regmap_write(rdev->regmap, reg, data);
  	mutex_unlock(&rdev->mutex);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(retu_write);
  
  static void retu_power_off(void)
  {
  	struct retu_dev *rdev = retu_pm_power_off;
  	int reg;
  
  	mutex_lock(&retu_pm_power_off->mutex);
  
  	/* Ignore power button state */
  	regmap_read(rdev->regmap, RETU_REG_CC1, &reg);
  	regmap_write(rdev->regmap, RETU_REG_CC1, reg | 2);
  
  	/* Expire watchdog immediately */
  	regmap_write(rdev->regmap, RETU_REG_WATCHDOG, 0);
  
  	/* Wait for poweroff */
  	for (;;)
  		cpu_relax();
  
  	mutex_unlock(&retu_pm_power_off->mutex);
  }
  
  static int retu_regmap_read(void *context, const void *reg, size_t reg_size,
  			    void *val, size_t val_size)
  {
  	int ret;
  	struct device *dev = context;
  	struct i2c_client *i2c = to_i2c_client(dev);
  
  	BUG_ON(reg_size != 1 || val_size != 2);
  
  	ret = i2c_smbus_read_word_data(i2c, *(u8 const *)reg);
  	if (ret < 0)
  		return ret;
  
  	*(u16 *)val = ret;
  	return 0;
  }
  
  static int retu_regmap_write(void *context, const void *data, size_t count)
  {
  	u8 reg;
  	u16 val;
  	struct device *dev = context;
  	struct i2c_client *i2c = to_i2c_client(dev);
  
  	BUG_ON(count != sizeof(reg) + sizeof(val));
  	memcpy(&reg, data, sizeof(reg));
  	memcpy(&val, data + sizeof(reg), sizeof(val));
  	return i2c_smbus_write_word_data(i2c, reg, val);
  }
  
  static struct regmap_bus retu_bus = {
  	.read = retu_regmap_read,
  	.write = retu_regmap_write,
  	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
  };

  static const struct regmap_config retu_config = {

  	.reg_bits = 8,
  	.val_bits = 16,
  };

  static int retu_probe(struct i2c_client *i2c, const struct i2c_device_id *id)

  {

  	struct retu_data const *rdat;

  	struct retu_dev *rdev;
  	int ret;

  	if (i2c->addr > ARRAY_SIZE(retu_data))
  		return -ENODEV;
  	rdat = &retu_data[i2c->addr - 1];

  	rdev = devm_kzalloc(&i2c->dev, sizeof(*rdev), GFP_KERNEL);
  	if (rdev == NULL)
  		return -ENOMEM;
  
  	i2c_set_clientdata(i2c, rdev);
  	rdev->dev = &i2c->dev;
  	mutex_init(&rdev->mutex);
  	rdev->regmap = devm_regmap_init(&i2c->dev, &retu_bus, &i2c->dev,
  					&retu_config);
  	if (IS_ERR(rdev->regmap))
  		return PTR_ERR(rdev->regmap);
  
  	ret = retu_read(rdev, RETU_REG_ASICR);
  	if (ret < 0) {

  		dev_err(rdev->dev, "could not read %s revision: %d
  ",
  			rdat->chip_name, ret);

  		return ret;
  	}

  	dev_info(rdev->dev, "%s%s%s v%d.%d found
  ", rdat->chip_name,
  		 (ret & RETU_REG_ASICR_VILMA) ? " & " : "",
  		 (ret & RETU_REG_ASICR_VILMA) ? rdat->companion_name : "",

  		 (ret >> 4) & 0x7, ret & 0xf);

  	/* Mask all interrupts. */
  	ret = retu_write(rdev, rdat->irq_chip->mask_base, 0xffff);

  	if (ret < 0)
  		return ret;
  
  	ret = regmap_add_irq_chip(rdev->regmap, i2c->irq, IRQF_ONESHOT, -1,

  				  rdat->irq_chip, &rdev->irq_data);

  	if (ret < 0)
  		return ret;

  	ret = mfd_add_devices(rdev->dev, -1, rdat->children, rdat->nchildren,

  			      NULL, regmap_irq_chip_get_base(rdev->irq_data),
  			      NULL);
  	if (ret < 0) {
  		regmap_del_irq_chip(i2c->irq, rdev->irq_data);
  		return ret;
  	}

  	if (i2c->addr == 1 && !pm_power_off) {

  		retu_pm_power_off = rdev;
  		pm_power_off	  = retu_power_off;
  	}
  
  	return 0;
  }

  static int retu_remove(struct i2c_client *i2c)

  {
  	struct retu_dev *rdev = i2c_get_clientdata(i2c);
  
  	if (retu_pm_power_off == rdev) {
  		pm_power_off	  = NULL;
  		retu_pm_power_off = NULL;
  	}
  	mfd_remove_devices(rdev->dev);
  	regmap_del_irq_chip(i2c->irq, rdev->irq_data);
  
  	return 0;
  }
  
  static const struct i2c_device_id retu_id[] = {
  	{ "retu-mfd", 0 },

  	{ "tahvo-mfd", 0 },

  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, retu_id);
  
  static struct i2c_driver retu_driver = {
  	.driver		= {
  		.name = "retu-mfd",

  	},
  	.probe		= retu_probe,
  	.remove		= retu_remove,
  	.id_table	= retu_id,
  };
  module_i2c_driver(retu_driver);
  
  MODULE_DESCRIPTION("Retu MFD driver");
  MODULE_AUTHOR("Juha Yrjölä");
  MODULE_AUTHOR("David Weinehall");
  MODULE_AUTHOR("Mikko Ylinen");
  MODULE_AUTHOR("Aaro Koskinen <aaro.koskinen@iki.fi>");
  MODULE_LICENSE("GPL");