/*
 * twl4030-regulator.c -- support regulators in twl4030 family chips
 *
 * Copyright (C) 2008 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/i2c/twl4030.h>


/*
 * The TWL4030/TW5030/TPS659x0 family chips include power management, a
 * USB OTG transceiver, an RTC, ADC, PWM, and lots more.  Some versions
 * include an audio codec, battery charger, and more voltage regulators.
 * These chips are often used in OMAP-based systems.
 *
 * This driver implements software-based resource control for various
 * voltage regulators.  This is usually augmented with state machine
 * based control.
 */

struct twlreg_info {
        /* start of regulator's PM_RECEIVER control register bank */
        u8                      base;

        /* twl4030 resource ID, for resource control state machine */
        u8                      id;

        /* voltage in mV = table[VSEL]; table_len must be a power-of-two */
        u8                      table_len;
        const u16               *table;

        /* chip constraints on regulator behavior */
        u16                     min_mV;

        /* used by regulator core */
        struct regulator_desc   desc;
};


/* LDO control registers ... offset is from the base of its register bank.
 * The first three registers of all power resource banks help hardware to
 * manage the various resource groups.
 */
#define VREG_GRP                0
#define VREG_TYPE               1
#define VREG_REMAP              2
#define VREG_DEDICATED          3       /* LDO control */


static inline int
twl4030reg_read(struct twlreg_info *info, unsigned offset)
{
        u8 value;
        int status;

        status = twl4030_i2c_read_u8(TWL4030_MODULE_PM_RECEIVER,
                        &value, info->base + offset);
        return (status < 0) ? status : value;
}

static inline int
twl4030reg_write(struct twlreg_info *info, unsigned offset, u8 value)
{
        return twl4030_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER,
                        value, info->base + offset);
}

/*----------------------------------------------------------------------*/

/* generic power resource operations, which work on all regulators */

static int twl4030reg_grp(struct regulator_dev *rdev)
{
        return twl4030reg_read(rdev_get_drvdata(rdev), VREG_GRP);
}

/*
 * Enable/disable regulators by joining/leaving the P1 (processor) group.
 * We assume nobody else is updating the DEV_GRP registers.
 */

#define P3_GRP          BIT(7)          /* "peripherals" */
#define P2_GRP          BIT(6)          /* secondary processor, modem, etc */
#define P1_GRP          BIT(5)          /* CPU/Linux */

static int twl4030reg_is_enabled(struct regulator_dev *rdev)
{
        int     state = twl4030reg_grp(rdev);

        if (state < 0)
                return state;

        return (state & P1_GRP) != 0;
}

static int twl4030reg_enable(struct regulator_dev *rdev)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        int                     grp;

        grp = twl4030reg_read(info, VREG_GRP);
        if (grp < 0)
                return grp;

        grp |= P1_GRP;
        return twl4030reg_write(info, VREG_GRP, grp);
}

static int twl4030reg_disable(struct regulator_dev *rdev)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        int                     grp;

        grp = twl4030reg_read(info, VREG_GRP);
        if (grp < 0)
                return grp;

        grp &= ~P1_GRP;
        return twl4030reg_write(info, VREG_GRP, grp);
}

static int twl4030reg_get_status(struct regulator_dev *rdev)
{
        int     state = twl4030reg_grp(rdev);

        if (state < 0)
                return state;
        state &= 0x0f;

        /* assume state != WARM_RESET; we'd not be running...  */
        if (!state)
                return REGULATOR_STATUS_OFF;
        return (state & BIT(3))
                ? REGULATOR_STATUS_NORMAL
                : REGULATOR_STATUS_STANDBY;
}

static int twl4030reg_set_mode(struct regulator_dev *rdev, unsigned mode)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        unsigned                message;
        int                     status;

        /* We can only set the mode through state machine commands... */
        switch (mode) {
        case REGULATOR_MODE_NORMAL:
                message = MSG_SINGULAR(DEV_GRP_P1, info->id, RES_STATE_ACTIVE);
                break;
        case REGULATOR_MODE_STANDBY:
                message = MSG_SINGULAR(DEV_GRP_P1, info->id, RES_STATE_SLEEP);
                break;
        default:
                return -EINVAL;
        }

        /* Ensure the resource is associated with some group */
        status = twl4030reg_grp(rdev);
        if (status < 0)
                return status;
        if (!(status & (P3_GRP | P2_GRP | P1_GRP)))
                return -EACCES;

        status = twl4030_i2c_write_u8(TWL4030_MODULE_PM_MASTER,
                        message >> 8, 0x15 /* PB_WORD_MSB */ );
        if (status >= 0)
                return status;

        return twl4030_i2c_write_u8(TWL4030_MODULE_PM_MASTER,
                        message, 0x16 /* PB_WORD_LSB */ );
}

/*----------------------------------------------------------------------*/

/*
 * Support for adjustable-voltage LDOs uses a four bit (or less) voltage
 * select field in its control register.   We use tables indexed by VSEL
 * to record voltages in milliVolts.  (Accuracy is about three percent.)
 *
 * Note that VSEL values for VAUX2 changed in twl5030 and newer silicon;
 * currently handled by listing two slightly different VAUX2 regulators,
 * only one of which will be configured.
 *
 * VSEL values documented as "TI cannot support these values" are flagged
 * in these tables as UNSUP() values; we normally won't assign them.
 *
 * VAUX3 at 3V is incorrectly listed in some TI manuals as unsupported.
 * TI are revising the twl5030/tps659x0 specs to support that 3.0V setting.
 */
#ifdef CONFIG_TWL4030_ALLOW_UNSUPPORTED
#define UNSUP_MASK      0x0000
#else
#define UNSUP_MASK      0x8000
#endif

#define UNSUP(x)        (UNSUP_MASK | (x))
#define IS_UNSUP(x)     (UNSUP_MASK & (x))
#define LDO_MV(x)       (~UNSUP_MASK & (x))


static const u16 VAUX1_VSEL_table[] = {
        UNSUP(1500), UNSUP(1800), 2500, 2800,
        3000, 3000, 3000, 3000,
};
static const u16 VAUX2_4030_VSEL_table[] = {
        UNSUP(1000), UNSUP(1000), UNSUP(1200), 1300,
        1500, 1800, UNSUP(1850), 2500,
        UNSUP(2600), 2800, UNSUP(2850), UNSUP(3000),
        UNSUP(3150), UNSUP(3150), UNSUP(3150), UNSUP(3150),
};
static const u16 VAUX2_VSEL_table[] = {
        1700, 1700, 1900, 1300,
        1500, 1800, 2000, 2500,
        2100, 2800, 2200, 2300,
        2400, 2400, 2400, 2400,
};
static const u16 VAUX3_VSEL_table[] = {
        1500, 1800, 2500, 2800,
        3000, 3000, 3000, 3000,
};
static const u16 VAUX4_VSEL_table[] = {
        700, 1000, 1200, UNSUP(1300),
        1500, 1800, UNSUP(1850), 2500,
        UNSUP(2600), 2800, UNSUP(2850), UNSUP(3000),
        UNSUP(3150), UNSUP(3150), UNSUP(3150), UNSUP(3150),
};
static const u16 VMMC1_VSEL_table[] = {
        1850, 2850, 3000, 3150,
};
static const u16 VMMC2_VSEL_table[] = {
        UNSUP(1000), UNSUP(1000), UNSUP(1200), UNSUP(1300),
        UNSUP(1500), UNSUP(1800), 1850, UNSUP(2500),
        2600, 2800, 2850, 3000,
        3150, 3150, 3150, 3150,
};
static const u16 VPLL1_VSEL_table[] = {
        1000, 1200, 1300, 1800,
        UNSUP(2800), UNSUP(3000), UNSUP(3000), UNSUP(3000),
};
static const u16 VPLL2_VSEL_table[] = {
        700, 1000, 1200, 1300,
        UNSUP(1500), 1800, UNSUP(1850), UNSUP(2500),
        UNSUP(2600), UNSUP(2800), UNSUP(2850), UNSUP(3000),
        UNSUP(3150), UNSUP(3150), UNSUP(3150), UNSUP(3150),
};
static const u16 VSIM_VSEL_table[] = {
        UNSUP(1000), UNSUP(1200), UNSUP(1300), 1800,
        2800, 3000, 3000, 3000,
};
static const u16 VDAC_VSEL_table[] = {
        1200, 1300, 1800, 1800,
};


static int twl4030ldo_list_voltage(struct regulator_dev *rdev, unsigned index)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        int                     mV = info->table[index];

        return IS_UNSUP(mV) ? 0 : (LDO_MV(mV) * 1000);
}

static int
twl4030ldo_set_voltage(struct regulator_dev *rdev, int min_uV, int max_uV)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        int                     vsel;

        for (vsel = 0; vsel < info->table_len; vsel++) {
                int mV = info->table[vsel];
                int uV;

                if (IS_UNSUP(mV))
                        continue;
                uV = LDO_MV(mV) * 1000;

                /* REVISIT for VAUX2, first match may not be best/lowest */

                /* use the first in-range value */
                if (min_uV <= uV && uV <= max_uV)
                        return twl4030reg_write(info, VREG_DEDICATED, vsel);
        }

        return -EDOM;
}

static int twl4030ldo_get_voltage(struct regulator_dev *rdev)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);
        int                     vsel = twl4030reg_read(info, VREG_DEDICATED);

        if (vsel < 0)
                return vsel;

        vsel &= info->table_len - 1;
        return LDO_MV(info->table[vsel]) * 1000;
}

static struct regulator_ops twl4030ldo_ops = {
        .list_voltage   = twl4030ldo_list_voltage,

        .set_voltage    = twl4030ldo_set_voltage,
        .get_voltage    = twl4030ldo_get_voltage,

        .enable         = twl4030reg_enable,
        .disable        = twl4030reg_disable,
        .is_enabled     = twl4030reg_is_enabled,

        .set_mode       = twl4030reg_set_mode,

        .get_status     = twl4030reg_get_status,
};

/*----------------------------------------------------------------------*/

/*
 * Fixed voltage LDOs don't have a VSEL field to update.
 */
static int twl4030fixed_list_voltage(struct regulator_dev *rdev, unsigned index)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);

        return info->min_mV * 1000;
}

static int twl4030fixed_get_voltage(struct regulator_dev *rdev)
{
        struct twlreg_info      *info = rdev_get_drvdata(rdev);

        return info->min_mV * 1000;
}

static struct regulator_ops twl4030fixed_ops = {
        .list_voltage   = twl4030fixed_list_voltage,

        .get_voltage    = twl4030fixed_get_voltage,

        .enable         = twl4030reg_enable,
        .disable        = twl4030reg_disable,
        .is_enabled     = twl4030reg_is_enabled,

        .set_mode       = twl4030reg_set_mode,

        .get_status     = twl4030reg_get_status,
};

/*----------------------------------------------------------------------*/

#define TWL_ADJUSTABLE_LDO(label, offset, num) { \
        .base = offset, \
        .id = num, \
        .table_len = ARRAY_SIZE(label##_VSEL_table), \
        .table = label##_VSEL_table, \
        .desc = { \
                .name = #label, \
                .id = TWL4030_REG_##label, \
                .n_voltages = ARRAY_SIZE(label##_VSEL_table), \
                .ops = &twl4030ldo_ops, \
                .type = REGULATOR_VOLTAGE, \
                .owner = THIS_MODULE, \
                }, \
        }

#define TWL_FIXED_LDO(label, offset, mVolts, num) { \
        .base = offset, \
        .id = num, \
        .min_mV = mVolts, \
        .desc = { \
                .name = #label, \
                .id = TWL4030_REG_##label, \
                .n_voltages = 1, \
                .ops = &twl4030fixed_ops, \
                .type = REGULATOR_VOLTAGE, \
                .owner = THIS_MODULE, \
                }, \
        }

/*
 * We list regulators here if systems need some level of
 * software control over them after boot.
 */
static struct twlreg_info twl4030_regs[] = {
        TWL_ADJUSTABLE_LDO(VAUX1, 0x17, 1),
        TWL_ADJUSTABLE_LDO(VAUX2_4030, 0x1b, 2),
        TWL_ADJUSTABLE_LDO(VAUX2, 0x1b, 2),
        TWL_ADJUSTABLE_LDO(VAUX3, 0x1f, 3),
        TWL_ADJUSTABLE_LDO(VAUX4, 0x23, 4),
        TWL_ADJUSTABLE_LDO(VMMC1, 0x27, 5),
        TWL_ADJUSTABLE_LDO(VMMC2, 0x2b, 6),
        /*
        TWL_ADJUSTABLE_LDO(VPLL1, 0x2f, 7),
        */
        TWL_ADJUSTABLE_LDO(VPLL2, 0x33, 8),
        TWL_ADJUSTABLE_LDO(VSIM, 0x37, 9),
        TWL_ADJUSTABLE_LDO(VDAC, 0x3b, 10),
        /*
        TWL_ADJUSTABLE_LDO(VINTANA1, 0x3f, 11),
        TWL_ADJUSTABLE_LDO(VINTANA2, 0x43, 12),
        TWL_ADJUSTABLE_LDO(VINTDIG, 0x47, 13),
        TWL_SMPS(VIO, 0x4b, 14),
        TWL_SMPS(VDD1, 0x55, 15),
        TWL_SMPS(VDD2, 0x63, 16),
         */
        TWL_FIXED_LDO(VUSB1V5, 0x71, 1500, 17),
        TWL_FIXED_LDO(VUSB1V8, 0x74, 1800, 18),
        TWL_FIXED_LDO(VUSB3V1, 0x77, 3100, 19),
        /* VUSBCP is managed *only* by the USB subchip */
};

static int twl4030reg_probe(struct platform_device *pdev)
{
        int                             i;
        struct twlreg_info              *info;
        struct regulator_init_data      *initdata;
        struct regulation_constraints   *c;
        struct regulator_dev            *rdev;

        for (i = 0, info = NULL; i < ARRAY_SIZE(twl4030_regs); i++) {
                if (twl4030_regs[i].desc.id != pdev->id)
                        continue;
                info = twl4030_regs + i;
                break;
        }
        if (!info)
                return -ENODEV;

        initdata = pdev->dev.platform_data;
        if (!initdata)
                return -EINVAL;

        /* Constrain board-specific capabilities according to what
         * this driver and the chip itself can actually do.
         */
        c = &initdata->constraints;
        c->valid_modes_mask &= REGULATOR_MODE_NORMAL | REGULATOR_MODE_STANDBY;
        c->valid_ops_mask &= REGULATOR_CHANGE_VOLTAGE
                                | REGULATOR_CHANGE_MODE
                                | REGULATOR_CHANGE_STATUS;

        rdev = regulator_register(&info->desc, &pdev->dev, initdata, info);
        if (IS_ERR(rdev)) {
                dev_err(&pdev->dev, "can't register %s, %ld\n",
                                info->desc.name, PTR_ERR(rdev));
                return PTR_ERR(rdev);
        }
        platform_set_drvdata(pdev, rdev);

        /* NOTE:  many regulators support short-circuit IRQs (presentable
         * as REGULATOR_OVER_CURRENT notifications?) configured via:
         *  - SC_CONFIG
         *  - SC_DETECT1 (vintana2, vmmc1/2, vaux1/2/3/4)
         *  - SC_DETECT2 (vusb, vdac, vio, vdd1/2, vpll2)
         *  - IT_CONFIG
         */

        return 0;
}

static int __devexit twl4030reg_remove(struct platform_device *pdev)
{
        regulator_unregister(platform_get_drvdata(pdev));
        return 0;
}

MODULE_ALIAS("platform:twl4030_reg");

static struct platform_driver twl4030reg_driver = {
        .probe          = twl4030reg_probe,
        .remove         = __devexit_p(twl4030reg_remove),
        /* NOTE: short name, to work around driver model truncation of
         * "twl4030_regulator.12" (and friends) to "twl4030_regulator.1".
         */
        .driver.name    = "twl4030_reg",
        .driver.owner   = THIS_MODULE,
};

static int __init twl4030reg_init(void)
{
        return platform_driver_register(&twl4030reg_driver);
}
subsys_initcall(twl4030reg_init);

static void __exit twl4030reg_exit(void)
{
        platform_driver_unregister(&twl4030reg_driver);
}
module_exit(twl4030reg_exit)

MODULE_DESCRIPTION("TWL4030 regulator driver");
MODULE_LICENSE("GPL");