/*
 * 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/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/mfd/ab3100.h>
#include <linux/mfd/abx500.h>
#include <linux/of.h>
#include <linux/regulator/of_regulator.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
 */
struct ab3100_regulator {
        struct regulator_dev *rdev;
        struct device *dev;
        struct ab3100_platform_data *plfdata;
        u8 regreg;
};

/* 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 unsigned int ldo_e_buck_typ_voltages[] = {
        1800000,
        1400000,
        1300000,
        1200000,
        1100000,
        1050000,
        900000,
};

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

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

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

static const unsigned int ldo_k_typ_voltages[] = {
        2750000,
        1800000,
};


/* The regulator devices */
static struct ab3100_regulator
ab3100_regulators[AB3100_NUM_REGULATORS] = {
        {
                .regreg = AB3100_LDO_A,
        },
        {
                .regreg = AB3100_LDO_C,
        },
        {
                .regreg = AB3100_LDO_D,
        },
        {
                .regreg = AB3100_LDO_E,
        },
        {
                .regreg = AB3100_LDO_F,
        },
        {
                .regreg = AB3100_LDO_G,
        },
        {
                .regreg = AB3100_LDO_H,
        },
        {
                .regreg = AB3100_LDO_K,
        },
        {
                .regreg = AB3100_LDO_EXT,
                /* No voltages for the external regulator */
        },
        {
                .regreg = AB3100_BUCK,
        },
};

/*
 * 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 = rdev_get_drvdata(reg);
        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\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 = abx500_set_register_interruptible(abreg->dev, 0, abreg->regreg,
                                                regval);
        if (err) {
                dev_warn(&reg->dev, "failed to set regid %d value\n",
                         abreg->regreg);
                return err;
        }

        return 0;
}

static int ab3100_disable_regulator(struct regulator_dev *reg)
{
        struct ab3100_regulator *abreg = rdev_get_drvdata(reg);
        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\n");
        if (abreg->regreg == AB3100_LDO_D) {
                dev_info(&reg->dev, "disabling LDO D - shut down system\n");
                /* 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\n",
                        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 = rdev_get_drvdata(reg);
        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\n",
                        abreg->regreg);
                return err;
        }

        return regval & AB3100_REG_ON_MASK;
}

static int ab3100_get_voltage_regulator(struct regulator_dev *reg)
{
        struct ab3100_regulator *abreg = rdev_get_drvdata(reg);
        u8 regval;
        int err;

        /*
         * 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\n",
                         abreg->regreg);
                return err;
        }

        /* The 3 highest bits index voltages */
        regval &= 0xE0;
        regval >>= 5;

        if (regval >= reg->desc->n_voltages) {
                dev_err(&reg->dev,
                        "regulator register %02x contains an illegal voltage setting\n",
                        abreg->regreg);
                return -EINVAL;
        }

        return reg->desc->volt_table[regval];
}

static int ab3100_set_voltage_regulator_sel(struct regulator_dev *reg,
                                            unsigned selector)
{
        struct ab3100_regulator *abreg = rdev_get_drvdata(reg);
        u8 regval;
        int err;

        err = abx500_get_register_interruptible(abreg->dev, 0,
                                                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 |= (selector << 5);

        err = abx500_set_register_interruptible(abreg->dev, 0,
                                                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 = rdev_get_drvdata(reg);
        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 = regulator_map_voltage_iterate(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\n",
                         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\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 = rdev_get_drvdata(reg);

        if (abreg->plfdata)
                return abreg->plfdata->external_voltage;
        else
                /* TODO: encode external voltage into device tree */
                return 0;
}

static struct regulator_ops regulator_ops_fixed = {
        .list_voltage = regulator_list_voltage_linear,
        .enable      = ab3100_enable_regulator,
        .disable     = ab3100_disable_regulator,
        .is_enabled  = ab3100_is_enabled_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_sel = ab3100_set_voltage_regulator_sel,
        .list_voltage = regulator_list_voltage_table,
};

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_sel = ab3100_set_voltage_regulator_sel,
        .set_suspend_voltage = ab3100_set_suspend_voltage_regulator,
        .list_voltage = regulator_list_voltage_table,
};

/*
 * 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,
                .n_voltages = 1,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .min_uV = LDO_A_VOLTAGE,
                .enable_time = 200,
        },
        {
                .name = "LDO_C",
                .id   = AB3100_LDO_C,
                .ops  = &regulator_ops_fixed,
                .n_voltages = 1,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .min_uV = LDO_C_VOLTAGE,
                .enable_time = 200,
        },
        {
                .name = "LDO_D",
                .id   = AB3100_LDO_D,
                .ops  = &regulator_ops_fixed,
                .n_voltages = 1,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .min_uV = LDO_D_VOLTAGE,
                .enable_time = 200,
        },
        {
                .name = "LDO_E",
                .id   = AB3100_LDO_E,
                .ops  = &regulator_ops_variable_sleepable,
                .n_voltages = ARRAY_SIZE(ldo_e_buck_typ_voltages),
                .volt_table = ldo_e_buck_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 200,
        },
        {
                .name = "LDO_F",
                .id   = AB3100_LDO_F,
                .ops  = &regulator_ops_variable,
                .n_voltages = ARRAY_SIZE(ldo_f_typ_voltages),
                .volt_table = ldo_f_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 600,
        },
        {
                .name = "LDO_G",
                .id   = AB3100_LDO_G,
                .ops  = &regulator_ops_variable,
                .n_voltages = ARRAY_SIZE(ldo_g_typ_voltages),
                .volt_table = ldo_g_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 400,
        },
        {
                .name = "LDO_H",
                .id   = AB3100_LDO_H,
                .ops  = &regulator_ops_variable,
                .n_voltages = ARRAY_SIZE(ldo_h_typ_voltages),
                .volt_table = ldo_h_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 200,
        },
        {
                .name = "LDO_K",
                .id   = AB3100_LDO_K,
                .ops  = &regulator_ops_variable,
                .n_voltages = ARRAY_SIZE(ldo_k_typ_voltages),
                .volt_table = ldo_k_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 200,
        },
        {
                .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),
                .volt_table = ldo_e_buck_typ_voltages,
                .type = REGULATOR_VOLTAGE,
                .owner = THIS_MODULE,
                .enable_time = 1000,
        },
};

static int ab3100_regulator_register(struct platform_device *pdev,
                                     struct ab3100_platform_data *plfdata,
                                     struct regulator_init_data *init_data,
                                     struct device_node *np,
                                     unsigned long id)
{
        struct regulator_desc *desc;
        struct ab3100_regulator *reg;
        struct regulator_dev *rdev;
        struct regulator_config config = { };
        int err, i;

        for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
                desc = &ab3100_regulator_desc[i];
                if (desc->id == id)
                        break;
        }
        if (desc->id != id)
                return -ENODEV;

        /* Same index used for this array */
        reg = &ab3100_regulators[i];

        /*
         * 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;
        if (plfdata) {
                reg->plfdata = plfdata;
                config.init_data = &plfdata->reg_constraints[i];
        } else if (np) {
                config.of_node = np;
                config.init_data = init_data;
        }
        config.dev = &pdev->dev;
        config.driver_data = reg;

        rdev = devm_regulator_register(&pdev->dev, desc, &config);
        if (IS_ERR(rdev)) {
                err = PTR_ERR(rdev);
                dev_err(&pdev->dev,
                        "%s: failed to register regulator %s err %d\n",
                        __func__, desc->name,
                        err);
                return err;
        }

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

static struct of_regulator_match ab3100_regulator_matches[] = {
        { .name = "ab3100_ldo_a", .driver_data = (void *) AB3100_LDO_A, },
        { .name = "ab3100_ldo_c", .driver_data = (void *) AB3100_LDO_C, },
        { .name = "ab3100_ldo_d", .driver_data = (void *) AB3100_LDO_D, },
        { .name = "ab3100_ldo_e", .driver_data = (void *) AB3100_LDO_E, },
        { .name = "ab3100_ldo_f", .driver_data = (void *) AB3100_LDO_F },
        { .name = "ab3100_ldo_g", .driver_data = (void *) AB3100_LDO_G },
        { .name = "ab3100_ldo_h", .driver_data = (void *) AB3100_LDO_H },
        { .name = "ab3100_ldo_k", .driver_data = (void *) AB3100_LDO_K },
        { .name = "ab3100_ext", .driver_data = (void *) AB3100_LDO_EXT },
        { .name = "ab3100_buck", .driver_data = (void *) AB3100_BUCK },
};

/*
 * Initial settings of ab3100 registers.
 * Common for below LDO regulator settings are that
 * bit 7-5 controls voltage. Bit 4 turns regulator ON(1) or OFF(0).
 * Bit 3-2 controls sleep enable and bit 1-0 controls sleep mode.
 */
/* LDO_A 0x16: 2.75V, ON, SLEEP_A, SLEEP OFF GND */
#define LDO_A_SETTING           0x16
/* LDO_C 0x10: 2.65V, ON, SLEEP_A or B, SLEEP full power */
#define LDO_C_SETTING           0x10
/* LDO_D 0x10: 2.65V, ON, sleep mode not used */
#define LDO_D_SETTING           0x10
/* LDO_E 0x10: 1.8V, ON, SLEEP_A or B, SLEEP full power */
#define LDO_E_SETTING           0x10
/* LDO_E SLEEP 0x00: 1.8V, not used, SLEEP_A or B, not used */
#define LDO_E_SLEEP_SETTING     0x00
/* LDO_F 0xD0: 2.5V, ON, SLEEP_A or B, SLEEP full power */
#define LDO_F_SETTING           0xD0
/* LDO_G 0x00: 2.85V, OFF, SLEEP_A or B, SLEEP full power */
#define LDO_G_SETTING           0x00
/* LDO_H 0x18: 2.75V, ON, SLEEP_B, SLEEP full power */
#define LDO_H_SETTING           0x18
/* LDO_K 0x00: 2.75V, OFF, SLEEP_A or B, SLEEP full power */
#define LDO_K_SETTING           0x00
/* LDO_EXT 0x00: Voltage not set, OFF, not used, not used */
#define LDO_EXT_SETTING         0x00
/* BUCK 0x7D: 1.2V, ON, SLEEP_A and B, SLEEP low power */
#define BUCK_SETTING    0x7D
/* BUCK SLEEP 0xAC: 1.05V, Not used, SLEEP_A and B, Not used */
#define BUCK_SLEEP_SETTING      0xAC

static const u8 ab3100_reg_initvals[] = {
        LDO_A_SETTING,
        LDO_C_SETTING,
        LDO_E_SETTING,
        LDO_E_SLEEP_SETTING,
        LDO_F_SETTING,
        LDO_G_SETTING,
        LDO_H_SETTING,
        LDO_K_SETTING,
        LDO_EXT_SETTING,
        BUCK_SETTING,
        BUCK_SLEEP_SETTING,
        LDO_D_SETTING,
};

static int ab3100_regulators_remove(struct platform_device *pdev)
{
        int i;

        for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
                struct ab3100_regulator *reg = &ab3100_regulators[i];

                reg->rdev = NULL;
        }
        return 0;
}

static int
ab3100_regulator_of_probe(struct platform_device *pdev, struct device_node *np)
{
        int err, i;

        /*
         * Set up the regulator registers, as was previously done with
         * platform data.
         */
        /* 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],
                                        ab3100_reg_initvals[i]);
                if (err) {
                        dev_err(&pdev->dev, "regulator initialization failed with error %d\n",
                                err);
                        return err;
                }
        }

        for (i = 0; i < ARRAY_SIZE(ab3100_regulator_matches); i++) {
                err = ab3100_regulator_register(
                        pdev, NULL, ab3100_regulator_matches[i].init_data,
                        ab3100_regulator_matches[i].of_node,
                        (unsigned long)ab3100_regulator_matches[i].driver_data);
                if (err) {
                        ab3100_regulators_remove(pdev);
                        return err;
                }
        }

        return 0;
}


static int ab3100_regulators_probe(struct platform_device *pdev)
{
        struct ab3100_platform_data *plfdata = dev_get_platdata(&pdev->dev);
        struct device_node *np = pdev->dev.of_node;
        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\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");

        if (np) {
                err = of_regulator_match(&pdev->dev, np,
                                         ab3100_regulator_matches,
                                         ARRAY_SIZE(ab3100_regulator_matches));
                if (err < 0) {
                        dev_err(&pdev->dev,
                                "Error parsing regulator init data: %d\n", err);
                        return err;
                }
                return ab3100_regulator_of_probe(pdev, np);
        }

        /* 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\n",
                                err);
                        return err;
                }
        }

        /* Register the regulators */
        for (i = 0; i < AB3100_NUM_REGULATORS; i++) {
                struct regulator_desc *desc = &ab3100_regulator_desc[i];

                err = ab3100_regulator_register(pdev, plfdata, NULL, NULL,
                                                desc->id);
                if (err) {
                        ab3100_regulators_remove(pdev);
                        return err;
                }
        }

        return 0;
}

static struct platform_driver ab3100_regulators_driver = {
        .driver = {
                .name  = "ab3100-regulators",
        },
        .probe = ab3100_regulators_probe,
        .remove = 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");