/*
   * drivers/regulator/ab3100.c
   *
   * Copyright (C) 2008-2009 ST-Ericsson AB
   * License terms: GNU General Public License (GPL) version 2
   * Low-level control of the AB3100 IC Low Dropout (LDO)
   * regulators, external regulator and buck converter
   * Author: Mattias Wallin <mattias.wallin@stericsson.com>
   * Author: Linus Walleij <linus.walleij@stericsson.com>
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/delay.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>

  #include <linux/mfd/abx500.h>

  #include <linux/mfd/core.h>

  
  /* LDO registers and some handy masking definitions for AB3100 */
  #define AB3100_LDO_A		0x40
  #define AB3100_LDO_C		0x41
  #define AB3100_LDO_D		0x42
  #define AB3100_LDO_E		0x43
  #define AB3100_LDO_E_SLEEP	0x44
  #define AB3100_LDO_F		0x45
  #define AB3100_LDO_G		0x46
  #define AB3100_LDO_H		0x47
  #define AB3100_LDO_H_SLEEP_MODE	0
  #define AB3100_LDO_H_SLEEP_EN	2
  #define AB3100_LDO_ON		4
  #define AB3100_LDO_H_VSEL_AC	5
  #define AB3100_LDO_K		0x48
  #define AB3100_LDO_EXT		0x49
  #define AB3100_BUCK		0x4A
  #define AB3100_BUCK_SLEEP	0x4B
  #define AB3100_REG_ON_MASK	0x10
  
  /**
   * struct ab3100_regulator
   * A struct passed around the individual regulator functions
   * @platform_device: platform device holding this regulator

   * @dev: handle to the device

   * @plfdata: AB3100 platform data passed in at probe time
   * @regreg: regulator register number in the AB3100
   * @fixed_voltage: a fixed voltage for this regulator, if this
   *          0 the voltages array is used instead.
   * @typ_voltages: an array of available typical voltages for
   *          this regulator
   * @voltages_len: length of the array of available voltages
   */
  struct ab3100_regulator {
  	struct regulator_dev *rdev;

  	struct device *dev;

  	struct ab3100_platform_data *plfdata;
  	u8 regreg;
  	int fixed_voltage;
  	int const *typ_voltages;
  	u8 voltages_len;
  };
  
  /* The order in which registers are initialized */
  static const u8 ab3100_reg_init_order[AB3100_NUM_REGULATORS+2] = {
  	AB3100_LDO_A,
  	AB3100_LDO_C,
  	AB3100_LDO_E,
  	AB3100_LDO_E_SLEEP,
  	AB3100_LDO_F,
  	AB3100_LDO_G,
  	AB3100_LDO_H,
  	AB3100_LDO_K,
  	AB3100_LDO_EXT,
  	AB3100_BUCK,
  	AB3100_BUCK_SLEEP,
  	AB3100_LDO_D,
  };
  
  /* Preset (hardware defined) voltages for these regulators */
  #define LDO_A_VOLTAGE 2750000
  #define LDO_C_VOLTAGE 2650000
  #define LDO_D_VOLTAGE 2650000

  static const int ldo_e_buck_typ_voltages[] = {

  	1800000,
  	1400000,
  	1300000,
  	1200000,
  	1100000,
  	1050000,
  	900000,
  };

  static const int ldo_f_typ_voltages[] = {

  	1800000,
  	1400000,
  	1300000,
  	1200000,
  	1100000,
  	1050000,
  	2500000,
  	2650000,
  };

  static const int ldo_g_typ_voltages[] = {

  	2850000,
  	2750000,
  	1800000,
  	1500000,
  };

  static const int ldo_h_typ_voltages[] = {

  	2750000,
  	1800000,
  	1500000,
  	1200000,
  };

  static const int ldo_k_typ_voltages[] = {

  	2750000,
  	1800000,
  };
  
  
  /* The regulator devices */
  static struct ab3100_regulator
  ab3100_regulators[AB3100_NUM_REGULATORS] = {
  	{
  		.regreg = AB3100_LDO_A,
  		.fixed_voltage = LDO_A_VOLTAGE,
  	},
  	{
  		.regreg = AB3100_LDO_C,
  		.fixed_voltage = LDO_C_VOLTAGE,
  	},
  	{
  		.regreg = AB3100_LDO_D,
  		.fixed_voltage = LDO_D_VOLTAGE,
  	},
  	{
  		.regreg = AB3100_LDO_E,
  		.typ_voltages = ldo_e_buck_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_e_buck_typ_voltages),
  	},
  	{
  		.regreg = AB3100_LDO_F,
  		.typ_voltages = ldo_f_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_f_typ_voltages),
  	},
  	{
  		.regreg = AB3100_LDO_G,
  		.typ_voltages = ldo_g_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_g_typ_voltages),
  	},
  	{
  		.regreg = AB3100_LDO_H,
  		.typ_voltages = ldo_h_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_h_typ_voltages),
  	},
  	{
  		.regreg = AB3100_LDO_K,
  		.typ_voltages = ldo_k_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_k_typ_voltages),
  	},
  	{
  		.regreg = AB3100_LDO_EXT,
  		/* No voltages for the external regulator */
  	},
  	{
  		.regreg = AB3100_BUCK,
  		.typ_voltages = ldo_e_buck_typ_voltages,
  		.voltages_len = ARRAY_SIZE(ldo_e_buck_typ_voltages),
  	},
  };
  
  /*
   * General functions for enable, disable and is_enabled used for
   * LDO: A,C,E,F,G,H,K,EXT and BUCK
   */
  static int ab3100_enable_regulator(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	int err;
  	u8 regval;

  	err = abx500_get_register_interruptible(abreg->dev, 0, abreg->regreg,

  						&regval);
  	if (err) {
  		dev_warn(&reg->dev, "failed to get regid %d value
  ",
  			 abreg->regreg);
  		return err;
  	}
  
  	/* The regulator is already on, no reason to go further */
  	if (regval & AB3100_REG_ON_MASK)
  		return 0;
  
  	regval |= AB3100_REG_ON_MASK;

  	err = abx500_set_register_interruptible(abreg->dev, 0, abreg->regreg,

  						regval);
  	if (err) {
  		dev_warn(&reg->dev, "failed to set regid %d value
  ",
  			 abreg->regreg);
  		return err;
  	}

  	return 0;
  }
  
  static int ab3100_disable_regulator(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	int err;
  	u8 regval;
  
  	/*
  	 * LDO D is a special regulator. When it is disabled, the entire
  	 * system is shut down. So this is handled specially.
  	 */

  	pr_info("Called ab3100_disable_regulator
  ");

  	if (abreg->regreg == AB3100_LDO_D) {

  		dev_info(&reg->dev, "disabling LDO D - shut down system
  ");

  		/* Setting LDO D to 0x00 cuts the power to the SoC */

  		return abx500_set_register_interruptible(abreg->dev, 0,

  							 AB3100_LDO_D, 0x00U);

  	}
  
  	/*
  	 * All other regulators are handled here
  	 */

  	err = abx500_get_register_interruptible(abreg->dev, 0, abreg->regreg,

  						&regval);
  	if (err) {
  		dev_err(&reg->dev, "unable to get register 0x%x
  ",
  			abreg->regreg);
  		return err;
  	}
  	regval &= ~AB3100_REG_ON_MASK;

  	return abx500_set_register_interruptible(abreg->dev, 0, abreg->regreg,

  						 regval);
  }
  
  static int ab3100_is_enabled_regulator(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	u8 regval;
  	int err;

  	err = abx500_get_register_interruptible(abreg->dev, 0, abreg->regreg,

  						&regval);
  	if (err) {
  		dev_err(&reg->dev, "unable to get register 0x%x
  ",
  			abreg->regreg);
  		return err;
  	}
  
  	return regval & AB3100_REG_ON_MASK;
  }
  
  static int ab3100_list_voltage_regulator(struct regulator_dev *reg,
  					 unsigned selector)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;

  	if (selector >= abreg->voltages_len)

  		return -EINVAL;
  	return abreg->typ_voltages[selector];
  }
  
  static int ab3100_get_voltage_regulator(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	u8 regval;
  	int err;
  
  	/* Return the voltage for fixed regulators immediately */
  	if (abreg->fixed_voltage)
  		return abreg->fixed_voltage;
  
  	/*
  	 * For variable types, read out setting and index into
  	 * supplied voltage list.
  	 */

  	err = abx500_get_register_interruptible(abreg->dev, 0,

  						abreg->regreg, &regval);
  	if (err) {
  		dev_warn(&reg->dev,
  			 "failed to get regulator value in register %02x
  ",
  			 abreg->regreg);
  		return err;
  	}
  
  	/* The 3 highest bits index voltages */
  	regval &= 0xE0;
  	regval >>= 5;

  	if (regval >= abreg->voltages_len) {

  		dev_err(&reg->dev,
  			"regulator register %02x contains an illegal voltage setting
  ",
  			abreg->regreg);
  		return -EINVAL;
  	}
  
  	return abreg->typ_voltages[regval];
  }
  
  static int ab3100_get_best_voltage_index(struct regulator_dev *reg,
  				   int min_uV, int max_uV)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	int i;
  	int bestmatch;
  	int bestindex;
  
  	/*
  	 * Locate the minimum voltage fitting the criteria on
  	 * this regulator. The switchable voltages are not
  	 * in strict falling order so we need to check them
  	 * all for the best match.
  	 */
  	bestmatch = INT_MAX;
  	bestindex = -1;
  	for (i = 0; i < abreg->voltages_len; i++) {
  		if (abreg->typ_voltages[i] <= max_uV &&
  		    abreg->typ_voltages[i] >= min_uV &&
  		    abreg->typ_voltages[i] < bestmatch) {
  			bestmatch = abreg->typ_voltages[i];
  			bestindex = i;
  		}
  	}
  
  	if (bestindex < 0) {
  		dev_warn(&reg->dev, "requested %d<=x<=%d uV, out of range!
  ",
  			 min_uV, max_uV);
  		return -EINVAL;
  	}
  	return bestindex;
  }
  
  static int ab3100_set_voltage_regulator(struct regulator_dev *reg,

  					int min_uV, int max_uV,
  					unsigned *selector)

  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	u8 regval;
  	int err;
  	int bestindex;
  
  	bestindex = ab3100_get_best_voltage_index(reg, min_uV, max_uV);
  	if (bestindex < 0)
  		return bestindex;

  	*selector = bestindex;

  	err = abx500_get_register_interruptible(abreg->dev, 0,

  						abreg->regreg, &regval);
  	if (err) {
  		dev_warn(&reg->dev,
  			 "failed to get regulator register %02x
  ",
  			 abreg->regreg);
  		return err;
  	}
  
  	/* The highest three bits control the variable regulators */
  	regval &= ~0xE0;
  	regval |= (bestindex << 5);

  	err = abx500_set_register_interruptible(abreg->dev, 0,

  						abreg->regreg, regval);
  	if (err)
  		dev_warn(&reg->dev, "failed to set regulator register %02x
  ",
  			abreg->regreg);
  
  	return err;
  }
  
  static int ab3100_set_suspend_voltage_regulator(struct regulator_dev *reg,
  						int uV)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  	u8 regval;
  	int err;
  	int bestindex;
  	u8 targetreg;
  
  	if (abreg->regreg == AB3100_LDO_E)
  		targetreg = AB3100_LDO_E_SLEEP;
  	else if (abreg->regreg == AB3100_BUCK)
  		targetreg = AB3100_BUCK_SLEEP;
  	else
  		return -EINVAL;
  
  	/* LDO E and BUCK have special suspend voltages you can set */
  	bestindex = ab3100_get_best_voltage_index(reg, uV, uV);

  	err = abx500_get_register_interruptible(abreg->dev, 0,

  						targetreg, &regval);
  	if (err) {
  		dev_warn(&reg->dev,
  			 "failed to get regulator register %02x
  ",
  			 targetreg);
  		return err;
  	}
  
  	/* The highest three bits control the variable regulators */
  	regval &= ~0xE0;
  	regval |= (bestindex << 5);

  	err = abx500_set_register_interruptible(abreg->dev, 0,

  						targetreg, regval);
  	if (err)
  		dev_warn(&reg->dev, "failed to set regulator register %02x
  ",
  			abreg->regreg);
  
  	return err;
  }
  
  /*
   * The external regulator can just define a fixed voltage.
   */
  static int ab3100_get_voltage_regulator_external(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  
  	return abreg->plfdata->external_voltage;
  }

  static int ab3100_enable_time_regulator(struct regulator_dev *reg)
  {
  	struct ab3100_regulator *abreg = reg->reg_data;
  
  	/* Per-regulator power on delay from spec */
  	switch (abreg->regreg) {
  	case AB3100_LDO_A: /* Fallthrough */
  	case AB3100_LDO_C: /* Fallthrough */
  	case AB3100_LDO_D: /* Fallthrough */
  	case AB3100_LDO_E: /* Fallthrough */
  	case AB3100_LDO_H: /* Fallthrough */
  	case AB3100_LDO_K:
  		return 200;
  	case AB3100_LDO_F:
  		return 600;
  	case AB3100_LDO_G:
  		return 400;
  	case AB3100_BUCK:
  		return 1000;
  	default:
  		break;
  	}
  	return 0;
  }

  static struct regulator_ops regulator_ops_fixed = {
  	.enable      = ab3100_enable_regulator,
  	.disable     = ab3100_disable_regulator,
  	.is_enabled  = ab3100_is_enabled_regulator,
  	.get_voltage = ab3100_get_voltage_regulator,

  	.enable_time = ab3100_enable_time_regulator,

  };
  
  static struct regulator_ops regulator_ops_variable = {
  	.enable      = ab3100_enable_regulator,
  	.disable     = ab3100_disable_regulator,
  	.is_enabled  = ab3100_is_enabled_regulator,
  	.get_voltage = ab3100_get_voltage_regulator,
  	.set_voltage = ab3100_set_voltage_regulator,
  	.list_voltage = ab3100_list_voltage_regulator,

  	.enable_time = ab3100_enable_time_regulator,

  };
  
  static struct regulator_ops regulator_ops_variable_sleepable = {
  	.enable      = ab3100_enable_regulator,
  	.disable     = ab3100_disable_regulator,
  	.is_enabled  = ab3100_is_enabled_regulator,
  	.get_voltage = ab3100_get_voltage_regulator,
  	.set_voltage = ab3100_set_voltage_regulator,
  	.set_suspend_voltage = ab3100_set_suspend_voltage_regulator,
  	.list_voltage = ab3100_list_voltage_regulator,

  	.enable_time = ab3100_enable_time_regulator,

  };
  
  /*
   * LDO EXT is an external regulator so it is really
   * not possible to set any voltage locally here, AB3100
   * is an on/off switch plain an simple. The external
   * voltage is defined in the board set-up if any.
   */
  static struct regulator_ops regulator_ops_external = {
  	.enable      = ab3100_enable_regulator,
  	.disable     = ab3100_disable_regulator,
  	.is_enabled  = ab3100_is_enabled_regulator,
  	.get_voltage = ab3100_get_voltage_regulator_external,
  };
  
  static struct regulator_desc
  ab3100_regulator_desc[AB3100_NUM_REGULATORS] = {
  	{
  		.name = "LDO_A",
  		.id   = AB3100_LDO_A,
  		.ops  = &regulator_ops_fixed,
  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_C",
  		.id   = AB3100_LDO_C,
  		.ops  = &regulator_ops_fixed,
  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_D",
  		.id   = AB3100_LDO_D,
  		.ops  = &regulator_ops_fixed,
  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_E",
  		.id   = AB3100_LDO_E,
  		.ops  = &regulator_ops_variable_sleepable,

  		.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_F",
  		.id   = AB3100_LDO_F,
  		.ops  = &regulator_ops_variable,

  		.n_voltages = ARRAY_SIZE(ldo_f_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_G",
  		.id   = AB3100_LDO_G,
  		.ops  = &regulator_ops_variable,

  		.n_voltages = ARRAY_SIZE(ldo_g_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_H",
  		.id   = AB3100_LDO_H,
  		.ops  = &regulator_ops_variable,

  		.n_voltages = ARRAY_SIZE(ldo_h_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_K",
  		.id   = AB3100_LDO_K,
  		.ops  = &regulator_ops_variable,

  		.n_voltages = ARRAY_SIZE(ldo_k_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "LDO_EXT",
  		.id   = AB3100_LDO_EXT,
  		.ops  = &regulator_ops_external,
  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  	{
  		.name = "BUCK",
  		.id   = AB3100_BUCK,
  		.ops  = &regulator_ops_variable_sleepable,

  		.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),

  		.type = REGULATOR_VOLTAGE,

  		.owner = THIS_MODULE,

  	},
  };
  
  /*
   * NOTE: the following functions are regulators pluralis - it is the
   * binding to the AB3100 core driver and the parent platform device
   * for all the different regulators.
   */

  static int __devinit ab3100_regulators_probe(struct platform_device *pdev)

  {

  	struct ab3100_platform_data *plfdata = mfd_get_data(pdev);

  	int err = 0;
  	u8 data;
  	int i;
  
  	/* Check chip state */

  	err = abx500_get_register_interruptible(&pdev->dev, 0,

  						AB3100_LDO_D, &data);
  	if (err) {
  		dev_err(&pdev->dev, "could not read initial status of LDO_D
  ");
  		return err;
  	}
  	if (data & 0x10)
  		dev_notice(&pdev->dev,
  			   "chip is already in active mode (Warm start)
  ");
  	else
  		dev_notice(&pdev->dev,
  			   "chip is in inactive mode (Cold start)
  ");
  
  	/* Set up regulators */
  	for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {

  		err = abx500_set_register_interruptible(&pdev->dev, 0,

  					ab3100_reg_init_order[i],
  					plfdata->reg_initvals[i]);
  		if (err) {
  			dev_err(&pdev->dev, "regulator initialization failed with error %d
  ",
  				err);
  			return err;
  		}
  	}

  	/* Register the regulators */
  	for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
  		struct ab3100_regulator *reg = &ab3100_regulators[i];
  		struct regulator_dev *rdev;
  
  		/*
  		 * Initialize per-regulator struct.
  		 * Inherit platform data, this comes down from the
  		 * i2c boarddata, from the machine. So if you want to
  		 * see what it looks like for a certain machine, go
  		 * into the machine I2C setup.
  		 */

  		reg->dev = &pdev->dev;

  		reg->plfdata = plfdata;
  
  		/*
  		 * Register the regulator, pass around
  		 * the ab3100_regulator struct
  		 */
  		rdev = regulator_register(&ab3100_regulator_desc[i],
  					  &pdev->dev,
  					  &plfdata->reg_constraints[i],
  					  reg);
  
  		if (IS_ERR(rdev)) {
  			err = PTR_ERR(rdev);
  			dev_err(&pdev->dev,
  				"%s: failed to register regulator %s err %d
  ",
  				__func__, ab3100_regulator_desc[i].name,
  				err);

  			/* remove the already registered regulators */

  			while (--i >= 0)

  				regulator_unregister(ab3100_regulators[i].rdev);

  			return err;
  		}
  
  		/* Then set a pointer back to the registered regulator */
  		reg->rdev = rdev;
  	}
  
  	return 0;
  }

  static int __devexit ab3100_regulators_remove(struct platform_device *pdev)

  {
  	int i;
  
  	for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
  		struct ab3100_regulator *reg = &ab3100_regulators[i];
  
  		regulator_unregister(reg->rdev);
  	}
  	return 0;
  }
  
  static struct platform_driver ab3100_regulators_driver = {
  	.driver = {
  		.name  = "ab3100-regulators",
  		.owner = THIS_MODULE,
  	},
  	.probe = ab3100_regulators_probe,

  	.remove = __devexit_p(ab3100_regulators_remove),

  };
  
  static __init int ab3100_regulators_init(void)
  {
  	return platform_driver_register(&ab3100_regulators_driver);
  }
  
  static __exit void ab3100_regulators_exit(void)
  {

  	platform_driver_unregister(&ab3100_regulators_driver);

  }
  
  subsys_initcall(ab3100_regulators_init);
  module_exit(ab3100_regulators_exit);
  
  MODULE_AUTHOR("Mattias Wallin <mattias.wallin@stericsson.com>");
  MODULE_DESCRIPTION("AB3100 Regulator driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:ab3100-regulators");