/*
   * Regulator driver for National Semiconductors LP3971 PMIC chip
   *
   *  Copyright (C) 2009 Samsung Electronics
   *  Author: Marek Szyprowski <m.szyprowski@samsung.com>
   *
   * Based on wm8350.c
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/bug.h>
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/kernel.h>

  #include <linux/module.h>

  #include <linux/regulator/driver.h>
  #include <linux/regulator/lp3971.h>

  #include <linux/slab.h>

  
  struct lp3971 {
  	struct device *dev;
  	struct mutex io_lock;
  	struct i2c_client *i2c;
  	int num_regulators;
  	struct regulator_dev **rdev;
  };
  
  static u8 lp3971_reg_read(struct lp3971 *lp3971, u8 reg);
  static int lp3971_set_bits(struct lp3971 *lp3971, u8 reg, u16 mask, u16 val);
  
  #define LP3971_SYS_CONTROL1_REG 0x07
  
  /* System control register 1 initial value,
     bits 4 and 5 are EPROM programmable */
  #define SYS_CONTROL1_INIT_VAL 0x40
  #define SYS_CONTROL1_INIT_MASK 0xCF
  
  #define LP3971_BUCK_VOL_ENABLE_REG 0x10
  #define LP3971_BUCK_VOL_CHANGE_REG 0x20
  
  /*	Voltage control registers shift:
  	LP3971_BUCK1 -> 0
  	LP3971_BUCK2 -> 4
  	LP3971_BUCK3 -> 6
  */

  #define BUCK_VOL_CHANGE_SHIFT(x) (((!!x) << 2) | (x & ~0x01))

  #define BUCK_VOL_CHANGE_FLAG_GO 0x01
  #define BUCK_VOL_CHANGE_FLAG_TARGET 0x02
  #define BUCK_VOL_CHANGE_FLAG_MASK 0x03
  
  #define LP3971_BUCK1_BASE 0x23
  #define LP3971_BUCK2_BASE 0x29
  #define LP3971_BUCK3_BASE 0x32

  static const int buck_base_addr[] = {

  	LP3971_BUCK1_BASE,
  	LP3971_BUCK2_BASE,
  	LP3971_BUCK3_BASE,
  };
  
  #define LP3971_BUCK_TARGET_VOL1_REG(x) (buck_base_addr[x])
  #define LP3971_BUCK_TARGET_VOL2_REG(x) (buck_base_addr[x]+1)

  static const int buck_voltage_map[] = {

  	   0,  800,  850,  900,  950, 1000, 1050, 1100,
  	1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500,
  	1550, 1600, 1650, 1700, 1800, 1900, 2500, 2800,
  	3000, 3300,
  };
  
  #define BUCK_TARGET_VOL_MASK 0x3f
  #define BUCK_TARGET_VOL_MIN_IDX 0x01
  #define BUCK_TARGET_VOL_MAX_IDX 0x19
  
  #define LP3971_BUCK_RAMP_REG(x)	(buck_base_addr[x]+2)
  
  #define LP3971_LDO_ENABLE_REG 0x12
  #define LP3971_LDO_VOL_CONTR_BASE 0x39
  
  /*	Voltage control registers:
  	LP3971_LDO1 -> LP3971_LDO_VOL_CONTR_BASE + 0
  	LP3971_LDO2 -> LP3971_LDO_VOL_CONTR_BASE + 0
  	LP3971_LDO3 -> LP3971_LDO_VOL_CONTR_BASE + 1
  	LP3971_LDO4 -> LP3971_LDO_VOL_CONTR_BASE + 1
  	LP3971_LDO5 -> LP3971_LDO_VOL_CONTR_BASE + 2
  */
  #define LP3971_LDO_VOL_CONTR_REG(x)	(LP3971_LDO_VOL_CONTR_BASE + (x >> 1))
  
  /*	Voltage control registers shift:
  	LP3971_LDO1 -> 0, LP3971_LDO2 -> 4
  	LP3971_LDO3 -> 0, LP3971_LDO4 -> 4
  	LP3971_LDO5 -> 0
  */
  #define LDO_VOL_CONTR_SHIFT(x) ((x & 1) << 2)
  #define LDO_VOL_CONTR_MASK 0x0f

  static const int ldo45_voltage_map[] = {

  	1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350,
  	1400, 1500, 1800, 1900, 2500, 2800, 3000, 3300,
  };

  static const int ldo123_voltage_map[] = {

  	1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500,
  	2600, 2700, 2800, 2900, 3000, 3100, 3200, 3300,
  };

  static const int *ldo_voltage_map[] = {

  	ldo123_voltage_map, /* LDO1 */
  	ldo123_voltage_map, /* LDO2 */
  	ldo123_voltage_map, /* LDO3 */
  	ldo45_voltage_map, /* LDO4 */
  	ldo45_voltage_map, /* LDO5 */
  };
  
  #define LDO_VOL_VALUE_MAP(x) (ldo_voltage_map[(x - LP3971_LDO1)])
  
  #define LDO_VOL_MIN_IDX 0x00
  #define LDO_VOL_MAX_IDX 0x0f
  
  static int lp3971_ldo_list_voltage(struct regulator_dev *dev, unsigned index)
  {
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	return 1000 * LDO_VOL_VALUE_MAP(ldo)[index];
  }
  
  static int lp3971_ldo_is_enabled(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	u16 mask = 1 << (1 + ldo);
  	u16 val;
  
  	val = lp3971_reg_read(lp3971, LP3971_LDO_ENABLE_REG);
  	return (val & mask) != 0;
  }
  
  static int lp3971_ldo_enable(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	u16 mask = 1 << (1 + ldo);
  
  	return lp3971_set_bits(lp3971, LP3971_LDO_ENABLE_REG, mask, mask);
  }
  
  static int lp3971_ldo_disable(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	u16 mask = 1 << (1 + ldo);
  
  	return lp3971_set_bits(lp3971, LP3971_LDO_ENABLE_REG, mask, 0);
  }
  
  static int lp3971_ldo_get_voltage(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	u16 val, reg;
  
  	reg = lp3971_reg_read(lp3971, LP3971_LDO_VOL_CONTR_REG(ldo));
  	val = (reg >> LDO_VOL_CONTR_SHIFT(ldo)) & LDO_VOL_CONTR_MASK;
  
  	return 1000 * LDO_VOL_VALUE_MAP(ldo)[val];
  }
  
  static int lp3971_ldo_set_voltage(struct regulator_dev *dev,

  				  int min_uV, int max_uV,
  				  unsigned int *selector)

  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  	int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
  	const int *vol_map = LDO_VOL_VALUE_MAP(ldo);
  	u16 val;
  
  	if (min_vol < vol_map[LDO_VOL_MIN_IDX] ||
  	    min_vol > vol_map[LDO_VOL_MAX_IDX])
  		return -EINVAL;
  
  	for (val = LDO_VOL_MIN_IDX; val <= LDO_VOL_MAX_IDX; val++)
  		if (vol_map[val] >= min_vol)
  			break;

  	if (val > LDO_VOL_MAX_IDX || vol_map[val] > max_vol)

  		return -EINVAL;

  	*selector = val;

  	return lp3971_set_bits(lp3971, LP3971_LDO_VOL_CONTR_REG(ldo),

  			LDO_VOL_CONTR_MASK << LDO_VOL_CONTR_SHIFT(ldo),
  			val << LDO_VOL_CONTR_SHIFT(ldo));

  }
  
  static struct regulator_ops lp3971_ldo_ops = {
  	.list_voltage = lp3971_ldo_list_voltage,
  	.is_enabled = lp3971_ldo_is_enabled,
  	.enable = lp3971_ldo_enable,
  	.disable = lp3971_ldo_disable,
  	.get_voltage = lp3971_ldo_get_voltage,
  	.set_voltage = lp3971_ldo_set_voltage,
  };
  
  static int lp3971_dcdc_list_voltage(struct regulator_dev *dev, unsigned index)
  {
  	return 1000 * buck_voltage_map[index];
  }
  
  static int lp3971_dcdc_is_enabled(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	u16 mask = 1 << (buck * 2);
  	u16 val;
  
  	val = lp3971_reg_read(lp3971, LP3971_BUCK_VOL_ENABLE_REG);
  	return (val & mask) != 0;
  }
  
  static int lp3971_dcdc_enable(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	u16 mask = 1 << (buck * 2);
  
  	return lp3971_set_bits(lp3971, LP3971_BUCK_VOL_ENABLE_REG, mask, mask);
  }
  
  static int lp3971_dcdc_disable(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	u16 mask = 1 << (buck * 2);
  
  	return lp3971_set_bits(lp3971, LP3971_BUCK_VOL_ENABLE_REG, mask, 0);
  }
  
  static int lp3971_dcdc_get_voltage(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	u16 reg;
  	int val;
  
  	reg = lp3971_reg_read(lp3971, LP3971_BUCK_TARGET_VOL1_REG(buck));
  	reg &= BUCK_TARGET_VOL_MASK;
  
  	if (reg <= BUCK_TARGET_VOL_MAX_IDX)
  		val = 1000 * buck_voltage_map[reg];
  	else {
  		val = 0;
  		dev_warn(&dev->dev, "chip reported incorrect voltage value.
  ");
  	}
  
  	return val;
  }
  
  static int lp3971_dcdc_set_voltage(struct regulator_dev *dev,

  				   int min_uV, int max_uV,
  				   unsigned int *selector)

  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	int min_vol = min_uV / 1000, max_vol = max_uV / 1000;
  	const int *vol_map = buck_voltage_map;
  	u16 val;
  	int ret;
  
  	if (min_vol < vol_map[BUCK_TARGET_VOL_MIN_IDX] ||
  	    min_vol > vol_map[BUCK_TARGET_VOL_MAX_IDX])
  		return -EINVAL;
  
  	for (val = BUCK_TARGET_VOL_MIN_IDX; val <= BUCK_TARGET_VOL_MAX_IDX;
  	     val++)
  		if (vol_map[val] >= min_vol)
  			break;

  	if (val > BUCK_TARGET_VOL_MAX_IDX || vol_map[val] > max_vol)

  		return -EINVAL;

  	*selector = val;

  	ret = lp3971_set_bits(lp3971, LP3971_BUCK_TARGET_VOL1_REG(buck),
  	       BUCK_TARGET_VOL_MASK, val);
  	if (ret)
  		return ret;
  
  	ret = lp3971_set_bits(lp3971, LP3971_BUCK_VOL_CHANGE_REG,
  	       BUCK_VOL_CHANGE_FLAG_MASK << BUCK_VOL_CHANGE_SHIFT(buck),
  	       BUCK_VOL_CHANGE_FLAG_GO << BUCK_VOL_CHANGE_SHIFT(buck));
  	if (ret)
  		return ret;
  
  	return lp3971_set_bits(lp3971, LP3971_BUCK_VOL_CHANGE_REG,
  	       BUCK_VOL_CHANGE_FLAG_MASK << BUCK_VOL_CHANGE_SHIFT(buck),
  	       0 << BUCK_VOL_CHANGE_SHIFT(buck));
  }
  
  static struct regulator_ops lp3971_dcdc_ops = {
  	.list_voltage = lp3971_dcdc_list_voltage,
  	.is_enabled = lp3971_dcdc_is_enabled,
  	.enable = lp3971_dcdc_enable,
  	.disable = lp3971_dcdc_disable,
  	.get_voltage = lp3971_dcdc_get_voltage,
  	.set_voltage = lp3971_dcdc_set_voltage,
  };
  
  static struct regulator_desc regulators[] = {
  	{
  		.name = "LDO1",
  		.id = LP3971_LDO1,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo123_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "LDO2",
  		.id = LP3971_LDO2,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo123_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "LDO3",
  		.id = LP3971_LDO3,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo123_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "LDO4",
  		.id = LP3971_LDO4,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo45_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "LDO5",
  		.id = LP3971_LDO5,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo45_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "DCDC1",
  		.id = LP3971_DCDC1,
  		.ops = &lp3971_dcdc_ops,
  		.n_voltages = ARRAY_SIZE(buck_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "DCDC2",
  		.id = LP3971_DCDC2,
  		.ops = &lp3971_dcdc_ops,
  		.n_voltages = ARRAY_SIZE(buck_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  	{
  		.name = "DCDC3",
  		.id = LP3971_DCDC3,
  		.ops = &lp3971_dcdc_ops,
  		.n_voltages = ARRAY_SIZE(buck_voltage_map),
  		.type = REGULATOR_VOLTAGE,
  		.owner = THIS_MODULE,
  	},
  };
  
  static int lp3971_i2c_read(struct i2c_client *i2c, char reg, int count,
  	u16 *dest)
  {
  	int ret;
  
  	if (count != 1)
  		return -EIO;
  	ret = i2c_smbus_read_byte_data(i2c, reg);

  	if (ret < 0)

  		return -EIO;
  
  	*dest = ret;
  	return 0;
  }
  
  static int lp3971_i2c_write(struct i2c_client *i2c, char reg, int count,
  	const u16 *src)
  {

  	if (count != 1)
  		return -EIO;

  	return i2c_smbus_write_byte_data(i2c, reg, *src);

  }
  
  static u8 lp3971_reg_read(struct lp3971 *lp3971, u8 reg)
  {
  	u16 val = 0;
  
  	mutex_lock(&lp3971->io_lock);
  
  	lp3971_i2c_read(lp3971->i2c, reg, 1, &val);
  
  	dev_dbg(lp3971->dev, "reg read 0x%02x -> 0x%02x
  ", (int)reg,
  		(unsigned)val&0xff);
  
  	mutex_unlock(&lp3971->io_lock);
  
  	return val & 0xff;
  }
  
  static int lp3971_set_bits(struct lp3971 *lp3971, u8 reg, u16 mask, u16 val)
  {
  	u16 tmp;
  	int ret;
  
  	mutex_lock(&lp3971->io_lock);
  
  	ret = lp3971_i2c_read(lp3971->i2c, reg, 1, &tmp);
  	tmp = (tmp & ~mask) | val;
  	if (ret == 0) {
  		ret = lp3971_i2c_write(lp3971->i2c, reg, 1, &tmp);
  		dev_dbg(lp3971->dev, "reg write 0x%02x -> 0x%02x
  ", (int)reg,
  			(unsigned)val&0xff);
  	}
  	mutex_unlock(&lp3971->io_lock);
  
  	return ret;
  }

  static int __devinit setup_regulators(struct lp3971 *lp3971,
  				      struct lp3971_platform_data *pdata)

  {
  	int i, err;

  
  	lp3971->num_regulators = pdata->num_regulators;
  	lp3971->rdev = kcalloc(pdata->num_regulators,
  				sizeof(struct regulator_dev *), GFP_KERNEL);

  	if (!lp3971->rdev) {
  		err = -ENOMEM;
  		goto err_nomem;
  	}

  
  	/* Instantiate the regulators */

  	for (i = 0; i < pdata->num_regulators; i++) {
  		struct lp3971_regulator_subdev *reg = &pdata->regulators[i];
  		lp3971->rdev[i] = regulator_register(&regulators[reg->id],

  				lp3971->dev, reg->initdata, lp3971, NULL);

  		if (IS_ERR(lp3971->rdev[i])) {
  			err = PTR_ERR(lp3971->rdev[i]);

  			dev_err(lp3971->dev, "regulator init failed: %d
  ",
  				err);
  			goto error;
  		}
  	}
  
  	return 0;

  error:

  	while (--i >= 0)
  		regulator_unregister(lp3971->rdev[i]);

  	kfree(lp3971->rdev);
  	lp3971->rdev = NULL;

  err_nomem:

  	return err;
  }
  
  static int __devinit lp3971_i2c_probe(struct i2c_client *i2c,
  			    const struct i2c_device_id *id)
  {
  	struct lp3971 *lp3971;
  	struct lp3971_platform_data *pdata = i2c->dev.platform_data;
  	int ret;
  	u16 val;

  	if (!pdata) {
  		dev_dbg(&i2c->dev, "No platform init data supplied
  ");
  		return -ENODEV;

  	}

  	lp3971 = kzalloc(sizeof(struct lp3971), GFP_KERNEL);
  	if (lp3971 == NULL)
  		return -ENOMEM;

  	lp3971->i2c = i2c;
  	lp3971->dev = &i2c->dev;

  
  	mutex_init(&lp3971->io_lock);
  
  	/* Detect LP3971 */
  	ret = lp3971_i2c_read(i2c, LP3971_SYS_CONTROL1_REG, 1, &val);
  	if (ret == 0 && (val & SYS_CONTROL1_INIT_MASK) != SYS_CONTROL1_INIT_VAL)
  		ret = -ENODEV;
  	if (ret < 0) {
  		dev_err(&i2c->dev, "failed to detect device
  ");
  		goto err_detect;
  	}

  	ret = setup_regulators(lp3971, pdata);
  	if (ret < 0)
  		goto err_detect;

  	i2c_set_clientdata(i2c, lp3971);

  	return 0;
  
  err_detect:

  	kfree(lp3971);

  	return ret;
  }
  
  static int __devexit lp3971_i2c_remove(struct i2c_client *i2c)
  {
  	struct lp3971 *lp3971 = i2c_get_clientdata(i2c);
  	int i;

  	for (i = 0; i < lp3971->num_regulators; i++)

  		regulator_unregister(lp3971->rdev[i]);

  	kfree(lp3971->rdev);

  	kfree(lp3971);
  
  	return 0;
  }
  
  static const struct i2c_device_id lp3971_i2c_id[] = {
         { "lp3971", 0 },
         { }
  };
  MODULE_DEVICE_TABLE(i2c, lp3971_i2c_id);
  
  static struct i2c_driver lp3971_i2c_driver = {
  	.driver = {
  		.name = "LP3971",
  		.owner = THIS_MODULE,
  	},
  	.probe    = lp3971_i2c_probe,

  	.remove   = __devexit_p(lp3971_i2c_remove),

  	.id_table = lp3971_i2c_id,
  };
  
  static int __init lp3971_module_init(void)
  {

  	int ret;

  
  	ret = i2c_add_driver(&lp3971_i2c_driver);
  	if (ret != 0)
  		pr_err("Failed to register I2C driver: %d
  ", ret);
  
  	return ret;
  }
  module_init(lp3971_module_init);
  
  static void __exit lp3971_module_exit(void)
  {
  	i2c_del_driver(&lp3971_i2c_driver);
  }
  module_exit(lp3971_module_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Marek Szyprowski <m.szyprowski@samsung.com>");
  MODULE_DESCRIPTION("LP3971 PMIC driver");