/*
   * 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;
  };
  
  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 unsigned int buck_voltage_map[] = {
  	      0,  800000,  850000,  900000,  950000, 1000000, 1050000, 1100000,
  	1150000, 1200000, 1250000, 1300000, 1350000, 1400000, 1450000, 1500000,
  	1550000, 1600000, 1650000, 1700000, 1800000, 1900000, 2500000, 2800000,
  	3000000, 3300000,
  };
  
  #define BUCK_TARGET_VOL_MASK 0x3f
  
  #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 unsigned int ldo45_voltage_map[] = {
  	1000000, 1050000, 1100000, 1150000, 1200000, 1250000, 1300000, 1350000,
  	1400000, 1500000, 1800000, 1900000, 2500000, 2800000, 3000000, 3300000,
  };
  
  static const unsigned int ldo123_voltage_map[] = {
  	1800000, 1900000, 2000000, 2100000, 2200000, 2300000, 2400000, 2500000,
  	2600000, 2700000, 2800000, 2900000, 3000000, 3100000, 3200000, 3300000,
  };
  
  #define LDO_VOL_MIN_IDX 0x00
  #define LDO_VOL_MAX_IDX 0x0f
  
  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_sel(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 val;
  }
  
  static int lp3971_ldo_set_voltage_sel(struct regulator_dev *dev,
  				      unsigned int selector)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int ldo = rdev_get_id(dev) - LP3971_LDO1;
  
  	return lp3971_set_bits(lp3971, LP3971_LDO_VOL_CONTR_REG(ldo),
  			LDO_VOL_CONTR_MASK << LDO_VOL_CONTR_SHIFT(ldo),
  			selector << LDO_VOL_CONTR_SHIFT(ldo));
  }
  
  static struct regulator_ops lp3971_ldo_ops = {
  	.list_voltage = regulator_list_voltage_table,
  	.map_voltage = regulator_map_voltage_ascend,
  	.is_enabled = lp3971_ldo_is_enabled,
  	.enable = lp3971_ldo_enable,
  	.disable = lp3971_ldo_disable,
  	.get_voltage_sel = lp3971_ldo_get_voltage_sel,
  	.set_voltage_sel = lp3971_ldo_set_voltage_sel,
  };
  
  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_sel(struct regulator_dev *dev)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	u16 reg;
  
  	reg = lp3971_reg_read(lp3971, LP3971_BUCK_TARGET_VOL1_REG(buck));
  	reg &= BUCK_TARGET_VOL_MASK;
  
  	return reg;
  }
  
  static int lp3971_dcdc_set_voltage_sel(struct regulator_dev *dev,
  				       unsigned int selector)
  {
  	struct lp3971 *lp3971 = rdev_get_drvdata(dev);
  	int buck = rdev_get_id(dev) - LP3971_DCDC1;
  	int ret;
  
  	ret = lp3971_set_bits(lp3971, LP3971_BUCK_TARGET_VOL1_REG(buck),
  	       BUCK_TARGET_VOL_MASK, selector);
  	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 = regulator_list_voltage_table,
  	.map_voltage = regulator_map_voltage_ascend,
  	.is_enabled = lp3971_dcdc_is_enabled,
  	.enable = lp3971_dcdc_enable,
  	.disable = lp3971_dcdc_disable,
  	.get_voltage_sel = lp3971_dcdc_get_voltage_sel,
  	.set_voltage_sel = lp3971_dcdc_set_voltage_sel,
  };
  
  static const struct regulator_desc regulators[] = {
  	{
  		.name = "LDO1",
  		.id = LP3971_LDO1,
  		.ops = &lp3971_ldo_ops,
  		.n_voltages = ARRAY_SIZE(ldo123_voltage_map),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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),
  		.volt_table = 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 setup_regulators(struct lp3971 *lp3971,
  				      struct lp3971_platform_data *pdata)
  {
  	int i, err;
  
  	/* Instantiate the regulators */
  	for (i = 0; i < pdata->num_regulators; i++) {
  		struct regulator_config config = { };
  		struct lp3971_regulator_subdev *reg = &pdata->regulators[i];
  		struct regulator_dev *rdev;
  
  		config.dev = lp3971->dev;
  		config.init_data = reg->initdata;
  		config.driver_data = lp3971;
  
  		rdev = devm_regulator_register(lp3971->dev,
  					       &regulators[reg->id], &config);
  		if (IS_ERR(rdev)) {
  			err = PTR_ERR(rdev);
  			dev_err(lp3971->dev, "regulator init failed: %d
  ",
  				err);
  			return err;
  		}
  	}
  
  	return 0;
  }
  
  static int lp3971_i2c_probe(struct i2c_client *i2c,
  			    const struct i2c_device_id *id)
  {
  	struct lp3971 *lp3971;
  	struct lp3971_platform_data *pdata = dev_get_platdata(&i2c->dev);
  	int ret;
  	u16 val;
  
  	if (!pdata) {
  		dev_dbg(&i2c->dev, "No platform init data supplied
  ");
  		return -ENODEV;
  	}
  
  	lp3971 = devm_kzalloc(&i2c->dev, 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
  ");
  		return ret;
  	}
  
  	ret = setup_regulators(lp3971, pdata);
  	if (ret < 0)
  		return ret;
  
  	i2c_set_clientdata(i2c, 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,
  	.id_table = lp3971_i2c_id,
  };
  
  module_i2c_driver(lp3971_i2c_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Marek Szyprowski <m.szyprowski@samsung.com>");
  MODULE_DESCRIPTION("LP3971 PMIC driver");