/*
 * 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>

/* 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\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 = 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\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 = 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\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 = 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 >= 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,
                                        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\n",
                         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\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 = 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 = 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 = pdev->dev.platform_data;
        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");

        /* 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 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, NULL);

                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);
                        /* 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");