wm831x-dcdc.c

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/*
 * wm831x-dcdc.c  --  DC-DC buck convertor driver for the WM831x series
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <[email protected]>
 *
 *  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/moduleparam.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/regulator.h>
#include <linux/mfd/wm831x/pdata.h>

#define WM831X_BUCKV_MAX_SELECTOR 0x68
#define WM831X_BUCKP_MAX_SELECTOR 0x66

#define WM831X_DCDC_MODE_FAST    0
#define WM831X_DCDC_MODE_NORMAL  1
#define WM831X_DCDC_MODE_IDLE    2
#define WM831X_DCDC_MODE_STANDBY 3

#define WM831X_DCDC_MAX_NAME 9

/* Register offsets in control block */
#define WM831X_DCDC_CONTROL_1     0
#define WM831X_DCDC_CONTROL_2     1
#define WM831X_DCDC_ON_CONFIG     2
#define WM831X_DCDC_SLEEP_CONTROL 3
#define WM831X_DCDC_DVS_CONTROL   4

/*
 * Shared
 */

struct wm831x_dcdc {
    char name[WM831X_DCDC_MAX_NAME];
    char supply_name[WM831X_DCDC_MAX_NAME];
    struct regulator_desc desc;
    int base;
    struct wm831x *wm831x;
    struct regulator_dev *regulator;
    int dvs_gpio;
    int dvs_gpio_state;
    int on_vsel;
    int dvs_vsel;
};

static unsigned int wm831x_dcdc_get_mode(struct regulator_dev *rdev)

{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
    int val;

    val = wm831x_reg_read(wm831x, reg);
    if (val < 0)
        return val;

    val = (val & WM831X_DC1_ON_MODE_MASK) >> WM831X_DC1_ON_MODE_SHIFT;

    switch (val) {
    case WM831X_DCDC_MODE_FAST:
        return REGULATOR_MODE_FAST;
    case WM831X_DCDC_MODE_NORMAL:
        return REGULATOR_MODE_NORMAL;
    case WM831X_DCDC_MODE_STANDBY:
        return REGULATOR_MODE_STANDBY;
    case WM831X_DCDC_MODE_IDLE:
        return REGULATOR_MODE_IDLE;
    default:
        BUG();
        return -EINVAL;
    }
}

static int wm831x_dcdc_set_mode_int(struct wm831x *wm831x, int reg,
                    unsigned int mode)
{
    int val;

    switch (mode) {
    case REGULATOR_MODE_FAST:
        val = WM831X_DCDC_MODE_FAST;
        break;
    case REGULATOR_MODE_NORMAL:
        val = WM831X_DCDC_MODE_NORMAL;
        break;
    case REGULATOR_MODE_STANDBY:
        val = WM831X_DCDC_MODE_STANDBY;
        break;
    case REGULATOR_MODE_IDLE:
        val = WM831X_DCDC_MODE_IDLE;
        break;
    default:
        return -EINVAL;
    }

    return wm831x_set_bits(wm831x, reg, WM831X_DC1_ON_MODE_MASK,
                   val << WM831X_DC1_ON_MODE_SHIFT);
}

static int wm831x_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_ON_CONFIG;

    return wm831x_dcdc_set_mode_int(wm831x, reg, mode);
}

static int wm831x_dcdc_set_suspend_mode(struct regulator_dev *rdev,
                    unsigned int mode)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_SLEEP_CONTROL;

    return wm831x_dcdc_set_mode_int(wm831x, reg, mode);
}

static int wm831x_dcdc_get_status(struct regulator_dev *rdev)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    int ret;

    /* First, check for errors */
    ret = wm831x_reg_read(wm831x, WM831X_DCDC_UV_STATUS);
    if (ret < 0)
        return ret;

    if (ret & (1 << rdev_get_id(rdev))) {
        dev_dbg(wm831x->dev, "DCDC%d under voltage\n",
            rdev_get_id(rdev) + 1);
        return REGULATOR_STATUS_ERROR;
    }

    /* DCDC1 and DCDC2 can additionally detect high voltage/current */
    if (rdev_get_id(rdev) < 2) {
        if (ret & (WM831X_DC1_OV_STS << rdev_get_id(rdev))) {
            dev_dbg(wm831x->dev, "DCDC%d over voltage\n",
                rdev_get_id(rdev) + 1);
            return REGULATOR_STATUS_ERROR;
        }

        if (ret & (WM831X_DC1_HC_STS << rdev_get_id(rdev))) {
            dev_dbg(wm831x->dev, "DCDC%d over current\n",
                rdev_get_id(rdev) + 1);
            return REGULATOR_STATUS_ERROR;
        }
    }

    /* Is the regulator on? */
    ret = wm831x_reg_read(wm831x, WM831X_DCDC_STATUS);
    if (ret < 0)
        return ret;
    if (!(ret & (1 << rdev_get_id(rdev))))
        return REGULATOR_STATUS_OFF;

    /* TODO: When we handle hardware control modes so we can report the
     * current mode. */
    return REGULATOR_STATUS_ON;
}

static irqreturn_t wm831x_dcdc_uv_irq(int irq, void *data)
{
    struct wm831x_dcdc *dcdc = data;

    regulator_notifier_call_chain(dcdc->regulator,
                      REGULATOR_EVENT_UNDER_VOLTAGE,
                      NULL);

    return IRQ_HANDLED;
}

static irqreturn_t wm831x_dcdc_oc_irq(int irq, void *data)
{
    struct wm831x_dcdc *dcdc = data;

    regulator_notifier_call_chain(dcdc->regulator,
                      REGULATOR_EVENT_OVER_CURRENT,
                      NULL);

    return IRQ_HANDLED;
}

/*
 * BUCKV specifics
 */

static int wm831x_buckv_list_voltage(struct regulator_dev *rdev,
                      unsigned selector)
{
    if (selector <= 0x8)
        return 600000;
    if (selector <= WM831X_BUCKV_MAX_SELECTOR)
        return 600000 + ((selector - 0x8) * 12500);
    return -EINVAL;
}

static int wm831x_buckv_map_voltage(struct regulator_dev *rdev,
                   int min_uV, int max_uV)
{
    u16 vsel;

    if (min_uV < 600000)
        vsel = 0;
    else if (min_uV <= 1800000)
        vsel = ((min_uV - 600000) / 12500) + 8;
    else
        return -EINVAL;

    if (wm831x_buckv_list_voltage(rdev, vsel) > max_uV)
        return -EINVAL;

    return vsel;
}

static int wm831x_buckv_set_dvs(struct regulator_dev *rdev, int state)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);

    if (state == dcdc->dvs_gpio_state)
        return 0;

    dcdc->dvs_gpio_state = state;
    gpio_set_value(dcdc->dvs_gpio, state);

    /* Should wait for DVS state change to be asserted if we have
     * a GPIO for it, for now assume the device is configured
     * for the fastest possible transition.
     */

    return 0;
}

static int wm831x_buckv_set_voltage_sel(struct regulator_dev *rdev,
                    unsigned vsel)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    int on_reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
    int dvs_reg = dcdc->base + WM831X_DCDC_DVS_CONTROL;
    int ret;

    /* If this value is already set then do a GPIO update if we can */
    if (dcdc->dvs_gpio && dcdc->on_vsel == vsel)
        return wm831x_buckv_set_dvs(rdev, 0);

    if (dcdc->dvs_gpio && dcdc->dvs_vsel == vsel)
        return wm831x_buckv_set_dvs(rdev, 1);

    /* Always set the ON status to the minimum voltage */
    ret = wm831x_set_bits(wm831x, on_reg, WM831X_DC1_ON_VSEL_MASK, vsel);
    if (ret < 0)
        return ret;
    dcdc->on_vsel = vsel;

    if (!dcdc->dvs_gpio)
        return ret;

    /* Kick the voltage transition now */
    ret = wm831x_buckv_set_dvs(rdev, 0);
    if (ret < 0)
        return ret;

    /*
     * If this VSEL is higher than the last one we've seen then
     * remember it as the DVS VSEL.  This is optimised for CPUfreq
     * usage where we want to get to the highest voltage very
     * quickly.
     */
    if (vsel > dcdc->dvs_vsel) {
        ret = wm831x_set_bits(wm831x, dvs_reg,
                      WM831X_DC1_DVS_VSEL_MASK,
                      dcdc->dvs_vsel);
        if (ret == 0)
            dcdc->dvs_vsel = vsel;
        else
            dev_warn(wm831x->dev,
                 "Failed to set DCDC DVS VSEL: %d\n", ret);
    }

    return 0;
}

static int wm831x_buckv_set_suspend_voltage(struct regulator_dev *rdev,
                        int uV)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_SLEEP_CONTROL;
    int vsel;

    vsel = wm831x_buckv_map_voltage(rdev, uV, uV);
    if (vsel < 0)
        return vsel;

    return wm831x_set_bits(wm831x, reg, WM831X_DC1_SLP_VSEL_MASK, vsel);
}

static int wm831x_buckv_get_voltage_sel(struct regulator_dev *rdev)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);

    if (dcdc->dvs_gpio && dcdc->dvs_gpio_state)
        return dcdc->dvs_vsel;
    else
        return dcdc->on_vsel;
}

/* Current limit options */
static u16 wm831x_dcdc_ilim[] = {
    125, 250, 375, 500, 625, 750, 875, 1000
};

static int wm831x_buckv_set_current_limit(struct regulator_dev *rdev,
                       int min_uA, int max_uA)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_CONTROL_2;
    int i;

    for (i = ARRAY_SIZE(wm831x_dcdc_ilim) - 1; i >= 0; i--) {
        if ((min_uA <= wm831x_dcdc_ilim[i]) &&
            (wm831x_dcdc_ilim[i] <= max_uA))
            return wm831x_set_bits(wm831x, reg,
                           WM831X_DC1_HC_THR_MASK,
                        i << WM831X_DC1_HC_THR_SHIFT);
    }

    return -EINVAL;
}

static int wm831x_buckv_get_current_limit(struct regulator_dev *rdev)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_CONTROL_2;
    int val;

    val = wm831x_reg_read(wm831x, reg);
    if (val < 0)
        return val;

    val = (val & WM831X_DC1_HC_THR_MASK) >> WM831X_DC1_HC_THR_SHIFT;
    return wm831x_dcdc_ilim[val];
}

static struct regulator_ops wm831x_buckv_ops = {
    .set_voltage_sel = wm831x_buckv_set_voltage_sel,
    .get_voltage_sel = wm831x_buckv_get_voltage_sel,
    .list_voltage = wm831x_buckv_list_voltage,
    .map_voltage = wm831x_buckv_map_voltage,
    .set_suspend_voltage = wm831x_buckv_set_suspend_voltage,
    .set_current_limit = wm831x_buckv_set_current_limit,
    .get_current_limit = wm831x_buckv_get_current_limit,

    .is_enabled = regulator_is_enabled_regmap,
    .enable = regulator_enable_regmap,
    .disable = regulator_disable_regmap,
    .get_status = wm831x_dcdc_get_status,
    .get_mode = wm831x_dcdc_get_mode,
    .set_mode = wm831x_dcdc_set_mode,
    .set_suspend_mode = wm831x_dcdc_set_suspend_mode,
};

/*
 * Set up DVS control.  We just log errors since we can still run
 * (with reduced performance) if we fail.
 */
static __devinit void wm831x_buckv_dvs_init(struct wm831x_dcdc *dcdc,
                        struct wm831x_buckv_pdata *pdata)
{
    struct wm831x *wm831x = dcdc->wm831x;
    int ret;
    u16 ctrl;

    if (!pdata || !pdata->dvs_gpio)
        return;

    /* gpiolib won't let us read the GPIO status so pick the higher
     * of the two existing voltages so we take it as platform data.
     */
    dcdc->dvs_gpio_state = pdata->dvs_init_state;

    ret = gpio_request_one(pdata->dvs_gpio,
                   dcdc->dvs_gpio_state ? GPIOF_INIT_HIGH : 0,
                   "DCDC DVS");
    if (ret < 0) {
        dev_err(wm831x->dev, "Failed to get %s DVS GPIO: %d\n",
            dcdc->name, ret);
        return;
    }

    dcdc->dvs_gpio = pdata->dvs_gpio;

    switch (pdata->dvs_control_src) {
    case 1:
        ctrl = 2 << WM831X_DC1_DVS_SRC_SHIFT;
        break;
    case 2:
        ctrl = 3 << WM831X_DC1_DVS_SRC_SHIFT;
        break;
    default:
        dev_err(wm831x->dev, "Invalid DVS control source %d for %s\n",
            pdata->dvs_control_src, dcdc->name);
        return;
    }

    /* If DVS_VSEL is set to the minimum value then raise it to ON_VSEL
     * to make bootstrapping a bit smoother.
     */
    if (!dcdc->dvs_vsel) {
        ret = wm831x_set_bits(wm831x,
                      dcdc->base + WM831X_DCDC_DVS_CONTROL,
                      WM831X_DC1_DVS_VSEL_MASK, dcdc->on_vsel);
        if (ret == 0)
            dcdc->dvs_vsel = dcdc->on_vsel;
        else
            dev_warn(wm831x->dev, "Failed to set DVS_VSEL: %d\n",
                 ret);
    }

    ret = wm831x_set_bits(wm831x, dcdc->base + WM831X_DCDC_DVS_CONTROL,
                  WM831X_DC1_DVS_SRC_MASK, ctrl);
    if (ret < 0) {
        dev_err(wm831x->dev, "Failed to set %s DVS source: %d\n",
            dcdc->name, ret);
    }
}

static __devinit int wm831x_buckv_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *pdata = wm831x->dev->platform_data;
    struct regulator_config config = { };
    int id;
    struct wm831x_dcdc *dcdc;
    struct resource *res;
    int ret, irq;

    if (pdata && pdata->wm831x_num)
        id = (pdata->wm831x_num * 10) + 1;
    else
        id = 0;
    id = pdev->id - id;

    dev_dbg(&pdev->dev, "Probing DCDC%d\n", id + 1);

    dcdc = devm_kzalloc(&pdev->dev,  sizeof(struct wm831x_dcdc),
                GFP_KERNEL);
    if (dcdc == NULL) {
        dev_err(&pdev->dev, "Unable to allocate private data\n");
        return -ENOMEM;
    }

    dcdc->wm831x = wm831x;

    res = platform_get_resource(pdev, IORESOURCE_REG, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "No REG resource\n");
        ret = -EINVAL;
        goto err;
    }
    dcdc->base = res->start;

    snprintf(dcdc->name, sizeof(dcdc->name), "DCDC%d", id + 1);
    dcdc->desc.name = dcdc->name;

    snprintf(dcdc->supply_name, sizeof(dcdc->supply_name),
         "DC%dVDD", id + 1);
    dcdc->desc.supply_name = dcdc->supply_name;

    dcdc->desc.id = id;
    dcdc->desc.type = REGULATOR_VOLTAGE;
    dcdc->desc.n_voltages = WM831X_BUCKV_MAX_SELECTOR + 1;
    dcdc->desc.ops = &wm831x_buckv_ops;
    dcdc->desc.owner = THIS_MODULE;
    dcdc->desc.enable_reg = WM831X_DCDC_ENABLE;
    dcdc->desc.enable_mask = 1 << id;

    ret = wm831x_reg_read(wm831x, dcdc->base + WM831X_DCDC_ON_CONFIG);
    if (ret < 0) {
        dev_err(wm831x->dev, "Failed to read ON VSEL: %d\n", ret);
        goto err;
    }
    dcdc->on_vsel = ret & WM831X_DC1_ON_VSEL_MASK;

    ret = wm831x_reg_read(wm831x, dcdc->base + WM831X_DCDC_DVS_CONTROL);
    if (ret < 0) {
        dev_err(wm831x->dev, "Failed to read DVS VSEL: %d\n", ret);
        goto err;
    }
    dcdc->dvs_vsel = ret & WM831X_DC1_DVS_VSEL_MASK;

    if (pdata && pdata->dcdc[id])
        wm831x_buckv_dvs_init(dcdc, pdata->dcdc[id]->driver_data);

    config.dev = pdev->dev.parent;
    if (pdata)
        config.init_data = pdata->dcdc[id];
    config.driver_data = dcdc;
    config.regmap = wm831x->regmap;

    dcdc->regulator = regulator_register(&dcdc->desc, &config);
    if (IS_ERR(dcdc->regulator)) {
        ret = PTR_ERR(dcdc->regulator);
        dev_err(wm831x->dev, "Failed to register DCDC%d: %d\n",
            id + 1, ret);
        goto err;
    }

    irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "UV"));
    ret = request_threaded_irq(irq, NULL, wm831x_dcdc_uv_irq,
                   IRQF_TRIGGER_RISING, dcdc->name, dcdc);
    if (ret != 0) {
        dev_err(&pdev->dev, "Failed to request UV IRQ %d: %d\n",
            irq, ret);
        goto err_regulator;
    }

    irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "HC"));
    ret = request_threaded_irq(irq, NULL, wm831x_dcdc_oc_irq,
                   IRQF_TRIGGER_RISING, dcdc->name, dcdc);
    if (ret != 0) {
        dev_err(&pdev->dev, "Failed to request HC IRQ %d: %d\n",
            irq, ret);
        goto err_uv;
    }

    platform_set_drvdata(pdev, dcdc);

    return 0;

err_uv:
    free_irq(wm831x_irq(wm831x, platform_get_irq_byname(pdev, "UV")),
         dcdc);
err_regulator:
    regulator_unregister(dcdc->regulator);
err:
    if (dcdc->dvs_gpio)
        gpio_free(dcdc->dvs_gpio);
    return ret;
}

static __devexit int wm831x_buckv_remove(struct platform_device *pdev)
{
    struct wm831x_dcdc *dcdc = platform_get_drvdata(pdev);
    struct wm831x *wm831x = dcdc->wm831x;

    platform_set_drvdata(pdev, NULL);

    free_irq(wm831x_irq(wm831x, platform_get_irq_byname(pdev, "HC")),
                dcdc);
    free_irq(wm831x_irq(wm831x, platform_get_irq_byname(pdev, "UV")),
                dcdc);
    regulator_unregister(dcdc->regulator);
    if (dcdc->dvs_gpio)
        gpio_free(dcdc->dvs_gpio);

    return 0;
}

static struct platform_driver wm831x_buckv_driver = {
    .probe = wm831x_buckv_probe,
    .remove = __devexit_p(wm831x_buckv_remove),
    .driver     = {
        .name   = "wm831x-buckv",
        .owner  = THIS_MODULE,
    },
};

/*
 * BUCKP specifics
 */

static int wm831x_buckp_set_suspend_voltage(struct regulator_dev *rdev, int uV)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    u16 reg = dcdc->base + WM831X_DCDC_SLEEP_CONTROL;
    int sel;

    sel = regulator_map_voltage_linear(rdev, uV, uV);
    if (sel < 0)
        return sel;

    return wm831x_set_bits(wm831x, reg, WM831X_DC3_ON_VSEL_MASK, sel);
}

static struct regulator_ops wm831x_buckp_ops = {
    .set_voltage_sel = regulator_set_voltage_sel_regmap,
    .get_voltage_sel = regulator_get_voltage_sel_regmap,
    .list_voltage = regulator_list_voltage_linear,
    .map_voltage = regulator_map_voltage_linear,
    .set_suspend_voltage = wm831x_buckp_set_suspend_voltage,

    .is_enabled = regulator_is_enabled_regmap,
    .enable = regulator_enable_regmap,
    .disable = regulator_disable_regmap,
    .get_status = wm831x_dcdc_get_status,
    .get_mode = wm831x_dcdc_get_mode,
    .set_mode = wm831x_dcdc_set_mode,
    .set_suspend_mode = wm831x_dcdc_set_suspend_mode,
};

static __devinit int wm831x_buckp_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *pdata = wm831x->dev->platform_data;
    struct regulator_config config = { };
    int id;
    struct wm831x_dcdc *dcdc;
    struct resource *res;
    int ret, irq;

    if (pdata && pdata->wm831x_num)
        id = (pdata->wm831x_num * 10) + 1;
    else
        id = 0;
    id = pdev->id - id;

    dev_dbg(&pdev->dev, "Probing DCDC%d\n", id + 1);

    dcdc = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_dcdc),
                GFP_KERNEL);
    if (dcdc == NULL) {
        dev_err(&pdev->dev, "Unable to allocate private data\n");
        return -ENOMEM;
    }

    dcdc->wm831x = wm831x;

    res = platform_get_resource(pdev, IORESOURCE_REG, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "No REG resource\n");
        ret = -EINVAL;
        goto err;
    }
    dcdc->base = res->start;

    snprintf(dcdc->name, sizeof(dcdc->name), "DCDC%d", id + 1);
    dcdc->desc.name = dcdc->name;

    snprintf(dcdc->supply_name, sizeof(dcdc->supply_name),
         "DC%dVDD", id + 1);
    dcdc->desc.supply_name = dcdc->supply_name;

    dcdc->desc.id = id;
    dcdc->desc.type = REGULATOR_VOLTAGE;
    dcdc->desc.n_voltages = WM831X_BUCKP_MAX_SELECTOR + 1;
    dcdc->desc.ops = &wm831x_buckp_ops;
    dcdc->desc.owner = THIS_MODULE;
    dcdc->desc.vsel_reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
    dcdc->desc.vsel_mask = WM831X_DC3_ON_VSEL_MASK;
    dcdc->desc.enable_reg = WM831X_DCDC_ENABLE;
    dcdc->desc.enable_mask = 1 << id;
    dcdc->desc.min_uV = 850000;
    dcdc->desc.uV_step = 25000;

    config.dev = pdev->dev.parent;
    if (pdata)
        config.init_data = pdata->dcdc[id];
    config.driver_data = dcdc;
    config.regmap = wm831x->regmap;

    dcdc->regulator = regulator_register(&dcdc->desc, &config);
    if (IS_ERR(dcdc->regulator)) {
        ret = PTR_ERR(dcdc->regulator);
        dev_err(wm831x->dev, "Failed to register DCDC%d: %d\n",
            id + 1, ret);
        goto err;
    }

    irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "UV"));
    ret = request_threaded_irq(irq, NULL, wm831x_dcdc_uv_irq,
                   IRQF_TRIGGER_RISING, dcdc->name, dcdc);
    if (ret != 0) {
        dev_err(&pdev->dev, "Failed to request UV IRQ %d: %d\n",
            irq, ret);
        goto err_regulator;
    }

    platform_set_drvdata(pdev, dcdc);

    return 0;

err_regulator:
    regulator_unregister(dcdc->regulator);
err:
    return ret;
}

static __devexit int wm831x_buckp_remove(struct platform_device *pdev)
{
    struct wm831x_dcdc *dcdc = platform_get_drvdata(pdev);

    platform_set_drvdata(pdev, NULL);

    free_irq(wm831x_irq(dcdc->wm831x, platform_get_irq_byname(pdev, "UV")),
                dcdc);
    regulator_unregister(dcdc->regulator);

    return 0;
}

static struct platform_driver wm831x_buckp_driver = {
    .probe = wm831x_buckp_probe,
    .remove = __devexit_p(wm831x_buckp_remove),
    .driver     = {
        .name   = "wm831x-buckp",
        .owner  = THIS_MODULE,
    },
};

/*
 * DCDC boost convertors
 */

static int wm831x_boostp_get_status(struct regulator_dev *rdev)
{
    struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = dcdc->wm831x;
    int ret;

    /* First, check for errors */
    ret = wm831x_reg_read(wm831x, WM831X_DCDC_UV_STATUS);
    if (ret < 0)
        return ret;

    if (ret & (1 << rdev_get_id(rdev))) {
        dev_dbg(wm831x->dev, "DCDC%d under voltage\n",
            rdev_get_id(rdev) + 1);
        return REGULATOR_STATUS_ERROR;
    }

    /* Is the regulator on? */
    ret = wm831x_reg_read(wm831x, WM831X_DCDC_STATUS);
    if (ret < 0)
        return ret;
    if (ret & (1 << rdev_get_id(rdev)))
        return REGULATOR_STATUS_ON;
    else
        return REGULATOR_STATUS_OFF;
}

static struct regulator_ops wm831x_boostp_ops = {
    .get_status = wm831x_boostp_get_status,

    .is_enabled = regulator_is_enabled_regmap,
    .enable = regulator_enable_regmap,
    .disable = regulator_disable_regmap,
};

static __devinit int wm831x_boostp_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *pdata = wm831x->dev->platform_data;
    struct regulator_config config = { };
    int id = pdev->id % ARRAY_SIZE(pdata->dcdc);
    struct wm831x_dcdc *dcdc;
    struct resource *res;
    int ret, irq;

    dev_dbg(&pdev->dev, "Probing DCDC%d\n", id + 1);

    if (pdata == NULL || pdata->dcdc[id] == NULL)
        return -ENODEV;

    dcdc = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_dcdc), GFP_KERNEL);
    if (dcdc == NULL) {
        dev_err(&pdev->dev, "Unable to allocate private data\n");
        return -ENOMEM;
    }

    dcdc->wm831x = wm831x;

    res = platform_get_resource(pdev, IORESOURCE_REG, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "No REG resource\n");
        ret = -EINVAL;
        goto err;
    }
    dcdc->base = res->start;

    snprintf(dcdc->name, sizeof(dcdc->name), "DCDC%d", id + 1);
    dcdc->desc.name = dcdc->name;
    dcdc->desc.id = id;
    dcdc->desc.type = REGULATOR_VOLTAGE;
    dcdc->desc.ops = &wm831x_boostp_ops;
    dcdc->desc.owner = THIS_MODULE;
    dcdc->desc.enable_reg = WM831X_DCDC_ENABLE;
    dcdc->desc.enable_mask = 1 << id;

    config.dev = pdev->dev.parent;
    if (pdata)
        config.init_data = pdata->dcdc[id];
    config.driver_data = dcdc;
    config.regmap = wm831x->regmap;

    dcdc->regulator = regulator_register(&dcdc->desc, &config);
    if (IS_ERR(dcdc->regulator)) {
        ret = PTR_ERR(dcdc->regulator);
        dev_err(wm831x->dev, "Failed to register DCDC%d: %d\n",
            id + 1, ret);
        goto err;
    }

    irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "UV"));
    ret = request_threaded_irq(irq, NULL, wm831x_dcdc_uv_irq,
                   IRQF_TRIGGER_RISING, dcdc->name,
                   dcdc);
    if (ret != 0) {
        dev_err(&pdev->dev, "Failed to request UV IRQ %d: %d\n",
            irq, ret);
        goto err_regulator;
    }

    platform_set_drvdata(pdev, dcdc);

    return 0;

err_regulator:
    regulator_unregister(dcdc->regulator);
err:
    return ret;
}

static __devexit int wm831x_boostp_remove(struct platform_device *pdev)
{
    struct wm831x_dcdc *dcdc = platform_get_drvdata(pdev);

    platform_set_drvdata(pdev, NULL);

    free_irq(wm831x_irq(dcdc->wm831x, platform_get_irq_byname(pdev, "UV")),
         dcdc);
    regulator_unregister(dcdc->regulator);

    return 0;
}

static struct platform_driver wm831x_boostp_driver = {
    .probe = wm831x_boostp_probe,
    .remove = __devexit_p(wm831x_boostp_remove),
    .driver     = {
        .name   = "wm831x-boostp",
        .owner  = THIS_MODULE,
    },
};

/*
 * External Power Enable
 *
 * These aren't actually DCDCs but look like them in hardware so share
 * code.
 */

#define WM831X_EPE_BASE 6

static struct regulator_ops wm831x_epe_ops = {
    .is_enabled = regulator_is_enabled_regmap,
    .enable = regulator_enable_regmap,
    .disable = regulator_disable_regmap,
    .get_status = wm831x_dcdc_get_status,
};

static __devinit int wm831x_epe_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *pdata = wm831x->dev->platform_data;
    struct regulator_config config = { };
    int id = pdev->id % ARRAY_SIZE(pdata->epe);
    struct wm831x_dcdc *dcdc;
    int ret;

    dev_dbg(&pdev->dev, "Probing EPE%d\n", id + 1);

    dcdc = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_dcdc), GFP_KERNEL);
    if (dcdc == NULL) {
        dev_err(&pdev->dev, "Unable to allocate private data\n");
        return -ENOMEM;
    }

    dcdc->wm831x = wm831x;

    /* For current parts this is correct; probably need to revisit
     * in future.
     */
    snprintf(dcdc->name, sizeof(dcdc->name), "EPE%d", id + 1);
    dcdc->desc.name = dcdc->name;
    dcdc->desc.id = id + WM831X_EPE_BASE; /* Offset in DCDC registers */
    dcdc->desc.ops = &wm831x_epe_ops;
    dcdc->desc.type = REGULATOR_VOLTAGE;
    dcdc->desc.owner = THIS_MODULE;
    dcdc->desc.enable_reg = WM831X_DCDC_ENABLE;
    dcdc->desc.enable_mask = 1 << dcdc->desc.id;

    config.dev = pdev->dev.parent;
    if (pdata)
        config.init_data = pdata->epe[id];
    config.driver_data = dcdc;
    config.regmap = wm831x->regmap;

    dcdc->regulator = regulator_register(&dcdc->desc, &config);
    if (IS_ERR(dcdc->regulator)) {
        ret = PTR_ERR(dcdc->regulator);
        dev_err(wm831x->dev, "Failed to register EPE%d: %d\n",
            id + 1, ret);
        goto err;
    }

    platform_set_drvdata(pdev, dcdc);

    return 0;

err:
    return ret;
}

static __devexit int wm831x_epe_remove(struct platform_device *pdev)
{
    struct wm831x_dcdc *dcdc = platform_get_drvdata(pdev);

    platform_set_drvdata(pdev, NULL);
    regulator_unregister(dcdc->regulator);

    return 0;
}

static struct platform_driver wm831x_epe_driver = {
    .probe = wm831x_epe_probe,
    .remove = __devexit_p(wm831x_epe_remove),
    .driver     = {
        .name   = "wm831x-epe",
        .owner  = THIS_MODULE,
    },
};

static int __init wm831x_dcdc_init(void)
{
    int ret;
    ret = platform_driver_register(&wm831x_buckv_driver);
    if (ret != 0)
        pr_err("Failed to register WM831x BUCKV driver: %d\n", ret);

    ret = platform_driver_register(&wm831x_buckp_driver);
    if (ret != 0)
        pr_err("Failed to register WM831x BUCKP driver: %d\n", ret);

    ret = platform_driver_register(&wm831x_boostp_driver);
    if (ret != 0)
        pr_err("Failed to register WM831x BOOST driver: %d\n", ret);

    ret = platform_driver_register(&wm831x_epe_driver);
    if (ret != 0)
        pr_err("Failed to register WM831x EPE driver: %d\n", ret);

    return 0;
}
subsys_initcall(wm831x_dcdc_init);

static void __exit wm831x_dcdc_exit(void)
{
    platform_driver_unregister(&wm831x_epe_driver);
    platform_driver_unregister(&wm831x_boostp_driver);
    platform_driver_unregister(&wm831x_buckp_driver);
    platform_driver_unregister(&wm831x_buckv_driver);
}
module_exit(wm831x_dcdc_exit);

/* Module information */
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x DC-DC convertor driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-buckv");
MODULE_ALIAS("platform:wm831x-buckp");
MODULE_ALIAS("platform:wm831x-epe");