drivers/regulator/ab3100.c - kernel/msm - Gitiles

 /*
  * 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/ab3100.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
  * @ab3100: handle to the AB3100 parent chip
  * @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 ab3100 *ab3100;
 	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 const ldo_e_buck_typ_voltages[] = {
 	1800000,
 	1400000,
 	1300000,
 	1200000,
 	1100000,
 	1050000,
 	900000,
 };

 static const int const ldo_f_typ_voltages[] = {
 	1800000,
 	1400000,
 	1300000,
 	1200000,
 	1100000,
 	1050000,
 	2500000,
 	2650000,
 };

 static const int const ldo_g_typ_voltages[] = {
 	2850000,
 	2750000,
 	1800000,
 	1500000,
 };

 static const int const ldo_h_typ_voltages[] = {
 	2750000,
 	1800000,
 	1500000,
 	1200000,
 };

 static const int const 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 = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
 						&regval);
 	if (err) {
 		dev_warn(&reg->dev, "failed to get regid %d value\n",
 			 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 = ab3100_set_register_interruptible(abreg->ab3100, abreg->regreg,
 						regval);
 	if (err) {
 		dev_warn(&reg->dev, "failed to set regid %d value\n",
 			 abreg->regreg);
 		return err;
 	}

 	/* 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:
 		udelay(200);
 		break;
 	case AB3100_LDO_F:
 		udelay(600);
 		break;
 	case AB3100_LDO_G:
 		udelay(400);
 		break;
 	case AB3100_BUCK:
 		mdelay(1);
 		break;
 	default:
 		break;
 	}

 	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.
 	 */
 	if (abreg->regreg == AB3100_LDO_D) {
 		int i;

 		dev_info(&reg->dev, "disabling LDO D - shut down system\n");
 		/*
 		 * Set regulators to default values, ignore any errors,
 		 * we're going DOWN
 		 */
 		for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
 			(void) ab3100_set_register_interruptible(abreg->ab3100,
 					ab3100_reg_init_order[i],
 					abreg->plfdata->reg_initvals[i]);
 		}

 		/* Setting LDO D to 0x00 cuts the power to the SoC */
 		return ab3100_set_register_interruptible(abreg->ab3100,
 							 AB3100_LDO_D, 0x00U);

 	}

 	/*
 	 * All other regulators are handled here
 	 */
 	err = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
 						&regval);
 	if (err) {
 		dev_err(&reg->dev, "unable to get register 0x%x\n",
 			abreg->regreg);
 		return err;
 	}
 	regval &= ~AB3100_REG_ON_MASK;
 	return ab3100_set_register_interruptible(abreg->ab3100, 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 = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
 						&regval);
 	if (err) {
 		dev_err(&reg->dev, "unable to get register 0x%x\n",
 			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 = ab3100_get_register_interruptible(abreg->ab3100,
 						abreg->regreg, &regval);
 	if (err) {
 		dev_warn(&reg->dev,
 			 "failed to get regulator value in register %02x\n",
 			 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\n",
 			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!\n",
 			 min_uV, max_uV);
 		return -EINVAL;
 	}
 	return bestindex;
 }

 static int ab3100_set_voltage_regulator(struct regulator_dev *reg,
 					int min_uV, int max_uV)
 {
 	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;

 	err = ab3100_get_register_interruptible(abreg->ab3100,
 						abreg->regreg, &regval);
 	if (err) {
 		dev_warn(&reg->dev,
 			 "failed to get regulator register %02x\n",
 			 abreg->regreg);
 		return err;
 	}

 	/* The highest three bits control the variable regulators */
 	regval &= ~0xE0;
 	regval |= (bestindex << 5);

 	err = ab3100_set_register_interruptible(abreg->ab3100,
 						abreg->regreg, regval);
 	if (err)
 		dev_warn(&reg->dev, "failed to set regulator register %02x\n",
 			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 = ab3100_get_register_interruptible(abreg->ab3100,
 						targetreg, &regval);
 	if (err) {
 		dev_warn(&reg->dev,
 			 "failed to get regulator register %02x\n",
 			 targetreg);
 		return err;
 	}

 	/* The highest three bits control the variable regulators */
 	regval &= ~0xE0;
 	regval |= (bestindex << 5);

 	err = ab3100_set_register_interruptible(abreg->ab3100,
 						targetreg, regval);
 	if (err)
 		dev_warn(&reg->dev, "failed to set regulator register %02x\n",
 			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 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,
 };

 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,
 };

 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,
 };

 /*
  * 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,
 	},
 	{
 		.name = "LDO_C",
 		.id   = AB3100_LDO_C,
 		.ops  = &regulator_ops_fixed,
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_D",
 		.id   = AB3100_LDO_D,
 		.ops  = &regulator_ops_fixed,
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_E",
 		.id   = AB3100_LDO_E,
 		.ops  = &regulator_ops_variable_sleepable,
 		.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_F",
 		.id   = AB3100_LDO_F,
 		.ops  = &regulator_ops_variable,
 		.n_voltages = ARRAY_SIZE(ldo_f_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_G",
 		.id   = AB3100_LDO_G,
 		.ops  = &regulator_ops_variable,
 		.n_voltages = ARRAY_SIZE(ldo_g_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_H",
 		.id   = AB3100_LDO_H,
 		.ops  = &regulator_ops_variable,
 		.n_voltages = ARRAY_SIZE(ldo_h_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_K",
 		.id   = AB3100_LDO_K,
 		.ops  = &regulator_ops_variable,
 		.n_voltages = ARRAY_SIZE(ldo_k_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "LDO_EXT",
 		.id   = AB3100_LDO_EXT,
 		.ops  = &regulator_ops_external,
 		.type = REGULATOR_VOLTAGE,
 	},
 	{
 		.name = "BUCK",
 		.id   = AB3100_BUCK,
 		.ops  = &regulator_ops_variable_sleepable,
 		.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),
 		.type = REGULATOR_VOLTAGE,
 	},
 };

 /*
  * 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 __init ab3100_regulators_probe(struct platform_device *pdev)
 {
 	struct ab3100_platform_data *plfdata = pdev->dev.platform_data;
 	struct ab3100 *ab3100 = platform_get_drvdata(pdev);
 	int err = 0;
 	u8 data;
 	int i;

 	/* Check chip state */
 	err = ab3100_get_register_interruptible(ab3100,
 						AB3100_LDO_D, &data);
 	if (err) {
 		dev_err(&pdev->dev, "could not read initial status of LDO_D\n");
 		return err;
 	}
 	if (data & 0x10)
 		dev_notice(&pdev->dev,
 			   "chip is already in active mode (Warm start)\n");
 	else
 		dev_notice(&pdev->dev,
 			   "chip is in inactive mode (Cold start)\n");

 	/* Set up regulators */
 	for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
 		err = ab3100_set_register_interruptible(ab3100,
 					ab3100_reg_init_order[i],
 					plfdata->reg_initvals[i]);
 		if (err) {
 			dev_err(&pdev->dev, "regulator initialization failed with error %d\n",
 				err);
 			return err;
 		}
 	}

 	if (err) {
 		dev_err(&pdev->dev,
 			"LDO D regulator initialization failed with error %d\n",
 			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->ab3100 = ab3100;
 		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\n",
 				__func__, ab3100_regulator_desc[i].name,
 				err);
 			i--;
 			/* remove the already registered regulators */
 			while (i > 0) {
 				regulator_unregister(ab3100_regulators[i].rdev);
 				i--;
 			}
 			return err;
 		}

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

 	return 0;
 }

 static int __exit 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 = __exit_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_register(&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");
	/*
	* 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/ab3100.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
	* @ab3100: handle to the AB3100 parent chip
	* @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 ab3100 *ab3100;
	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 const ldo_e_buck_typ_voltages[] = {
	1800000,
	1400000,
	1300000,
	1200000,
	1100000,
	1050000,
	900000,
	};

	static const int const ldo_f_typ_voltages[] = {
	1800000,
	1400000,
	1300000,
	1200000,
	1100000,
	1050000,
	2500000,
	2650000,
	};

	static const int const ldo_g_typ_voltages[] = {
	2850000,
	2750000,
	1800000,
	1500000,
	};

	static const int const ldo_h_typ_voltages[] = {
	2750000,
	1800000,
	1500000,
	1200000,
	};

	static const int const 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 = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
	&regval);
	if (err) {
	dev_warn(&reg->dev, "failed to get regid %d value\n",
	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 = ab3100_set_register_interruptible(abreg->ab3100, abreg->regreg,
	regval);
	if (err) {
	dev_warn(&reg->dev, "failed to set regid %d value\n",
	abreg->regreg);
	return err;
	}

	/* 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:
	udelay(200);
	break;
	case AB3100_LDO_F:
	udelay(600);
	break;
	case AB3100_LDO_G:
	udelay(400);
	break;
	case AB3100_BUCK:
	mdelay(1);
	break;
	default:
	break;
	}

	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.
	*/
	if (abreg->regreg == AB3100_LDO_D) {
	int i;

	dev_info(&reg->dev, "disabling LDO D - shut down system\n");
	/*
	* Set regulators to default values, ignore any errors,
	* we're going DOWN
	*/
	for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
	(void) ab3100_set_register_interruptible(abreg->ab3100,
	ab3100_reg_init_order[i],
	abreg->plfdata->reg_initvals[i]);
	}

	/* Setting LDO D to 0x00 cuts the power to the SoC */
	return ab3100_set_register_interruptible(abreg->ab3100,
	AB3100_LDO_D, 0x00U);

	}

	/*
	* All other regulators are handled here
	*/
	err = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
	&regval);
	if (err) {
	dev_err(&reg->dev, "unable to get register 0x%x\n",
	abreg->regreg);
	return err;
	}
	regval &= ~AB3100_REG_ON_MASK;
	return ab3100_set_register_interruptible(abreg->ab3100, 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 = ab3100_get_register_interruptible(abreg->ab3100, abreg->regreg,
	&regval);
	if (err) {
	dev_err(&reg->dev, "unable to get register 0x%x\n",
	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 = ab3100_get_register_interruptible(abreg->ab3100,
	abreg->regreg, &regval);
	if (err) {
	dev_warn(&reg->dev,
	"failed to get regulator value in register %02x\n",
	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\n",
	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!\n",
	min_uV, max_uV);
	return -EINVAL;
	}
	return bestindex;
	}

	static int ab3100_set_voltage_regulator(struct regulator_dev *reg,
	int min_uV, int max_uV)
	{
	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;

	err = ab3100_get_register_interruptible(abreg->ab3100,
	abreg->regreg, &regval);
	if (err) {
	dev_warn(&reg->dev,
	"failed to get regulator register %02x\n",
	abreg->regreg);
	return err;
	}

	/* The highest three bits control the variable regulators */
	regval &= ~0xE0;
	regval \|= (bestindex << 5);

	err = ab3100_set_register_interruptible(abreg->ab3100,
	abreg->regreg, regval);
	if (err)
	dev_warn(&reg->dev, "failed to set regulator register %02x\n",
	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 = ab3100_get_register_interruptible(abreg->ab3100,
	targetreg, &regval);
	if (err) {
	dev_warn(&reg->dev,
	"failed to get regulator register %02x\n",
	targetreg);
	return err;
	}

	/* The highest three bits control the variable regulators */
	regval &= ~0xE0;
	regval \|= (bestindex << 5);

	err = ab3100_set_register_interruptible(abreg->ab3100,
	targetreg, regval);
	if (err)
	dev_warn(&reg->dev, "failed to set regulator register %02x\n",
	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 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,
	};

	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,
	};

	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,
	};

	/*
	* 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,
	},
	{
	.name = "LDO_C",
	.id = AB3100_LDO_C,
	.ops = &regulator_ops_fixed,
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_D",
	.id = AB3100_LDO_D,
	.ops = &regulator_ops_fixed,
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_E",
	.id = AB3100_LDO_E,
	.ops = &regulator_ops_variable_sleepable,
	.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_F",
	.id = AB3100_LDO_F,
	.ops = &regulator_ops_variable,
	.n_voltages = ARRAY_SIZE(ldo_f_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_G",
	.id = AB3100_LDO_G,
	.ops = &regulator_ops_variable,
	.n_voltages = ARRAY_SIZE(ldo_g_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_H",
	.id = AB3100_LDO_H,
	.ops = &regulator_ops_variable,
	.n_voltages = ARRAY_SIZE(ldo_h_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_K",
	.id = AB3100_LDO_K,
	.ops = &regulator_ops_variable,
	.n_voltages = ARRAY_SIZE(ldo_k_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "LDO_EXT",
	.id = AB3100_LDO_EXT,
	.ops = &regulator_ops_external,
	.type = REGULATOR_VOLTAGE,
	},
	{
	.name = "BUCK",
	.id = AB3100_BUCK,
	.ops = &regulator_ops_variable_sleepable,
	.n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),
	.type = REGULATOR_VOLTAGE,
	},
	};

	/*
	* 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 __init ab3100_regulators_probe(struct platform_device *pdev)
	{
	struct ab3100_platform_data *plfdata = pdev->dev.platform_data;
	struct ab3100 *ab3100 = platform_get_drvdata(pdev);
	int err = 0;
	u8 data;
	int i;

	/* Check chip state */
	err = ab3100_get_register_interruptible(ab3100,
	AB3100_LDO_D, &data);
	if (err) {
	dev_err(&pdev->dev, "could not read initial status of LDO_D\n");
	return err;
	}
	if (data & 0x10)
	dev_notice(&pdev->dev,
	"chip is already in active mode (Warm start)\n");
	else
	dev_notice(&pdev->dev,
	"chip is in inactive mode (Cold start)\n");

	/* Set up regulators */
	for (i = 0; i < ARRAY_SIZE(ab3100_reg_init_order); i++) {
	err = ab3100_set_register_interruptible(ab3100,
	ab3100_reg_init_order[i],
	plfdata->reg_initvals[i]);
	if (err) {
	dev_err(&pdev->dev, "regulator initialization failed with error %d\n",
	err);
	return err;
	}
	}

	if (err) {
	dev_err(&pdev->dev,
	"LDO D regulator initialization failed with error %d\n",
	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->ab3100 = ab3100;
	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\n",
	__func__, ab3100_regulator_desc[i].name,
	err);
	i--;
	/* remove the already registered regulators */
	while (i > 0) {
	regulator_unregister(ab3100_regulators[i].rdev);
	i--;
	}
	return err;
	}

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

	return 0;
	}

	static int __exit 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 = __exit_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_register(&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");