wm831x-isink.c

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/*
 * wm831x-isink.c  --  Current sink 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/slab.h>

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

#define WM831X_ISINK_MAX_NAME 7

struct wm831x_isink {
    char name[WM831X_ISINK_MAX_NAME];
    struct regulator_desc desc;
    int reg;
    struct wm831x *wm831x;
    struct regulator_dev *regulator;
};

static int wm831x_isink_enable(struct regulator_dev *rdev)
{
    struct wm831x_isink *isink = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = isink->wm831x;
    int ret;

    /* We have a two stage enable: first start the ISINK... */
    ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA,
                  WM831X_CS1_ENA);
    if (ret != 0)
        return ret;

    /* ...then enable drive */
    ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE,
                  WM831X_CS1_DRIVE);
    if (ret != 0)
        wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);

    return ret;

}

static int wm831x_isink_disable(struct regulator_dev *rdev)
{
    struct wm831x_isink *isink = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = isink->wm831x;
    int ret;

    ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_DRIVE, 0);
    if (ret < 0)
        return ret;

    ret = wm831x_set_bits(wm831x, isink->reg, WM831X_CS1_ENA, 0);
    if (ret < 0)
        return ret;

    return ret;

}

static int wm831x_isink_is_enabled(struct regulator_dev *rdev)
{
    struct wm831x_isink *isink = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = isink->wm831x;
    int ret;

    ret = wm831x_reg_read(wm831x, isink->reg);
    if (ret < 0)
        return ret;

    if ((ret & (WM831X_CS1_ENA | WM831X_CS1_DRIVE)) ==
        (WM831X_CS1_ENA | WM831X_CS1_DRIVE))
        return 1;
    else
        return 0;
}

static int wm831x_isink_set_current(struct regulator_dev *rdev,
                    int min_uA, int max_uA)
{
    struct wm831x_isink *isink = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = isink->wm831x;
    int ret, i;

    for (i = 0; i < ARRAY_SIZE(wm831x_isinkv_values); i++) {
        int val = wm831x_isinkv_values[i];
        if (min_uA <= val && val <= max_uA) {
            ret = wm831x_set_bits(wm831x, isink->reg,
                          WM831X_CS1_ISEL_MASK, i);
            return ret;
        }
    }

    return -EINVAL;
}

static int wm831x_isink_get_current(struct regulator_dev *rdev)
{
    struct wm831x_isink *isink = rdev_get_drvdata(rdev);
    struct wm831x *wm831x = isink->wm831x;
    int ret;

    ret = wm831x_reg_read(wm831x, isink->reg);
    if (ret < 0)
        return ret;

    ret &= WM831X_CS1_ISEL_MASK;
    if (ret > WM831X_ISINK_MAX_ISEL)
        ret = WM831X_ISINK_MAX_ISEL;

    return wm831x_isinkv_values[ret];
}

static struct regulator_ops wm831x_isink_ops = {
    .is_enabled = wm831x_isink_is_enabled,
    .enable = wm831x_isink_enable,
    .disable = wm831x_isink_disable,
    .set_current_limit = wm831x_isink_set_current,
    .get_current_limit = wm831x_isink_get_current,
};

static irqreturn_t wm831x_isink_irq(int irq, void *data)
{
    struct wm831x_isink *isink = data;

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

    return IRQ_HANDLED;
}


static __devinit int wm831x_isink_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *pdata = wm831x->dev->platform_data;
    struct wm831x_isink *isink;
    int id = pdev->id % ARRAY_SIZE(pdata->isink);
    struct regulator_config config = { };
    struct resource *res;
    int ret, irq;

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

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

    isink = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_isink),
                 GFP_KERNEL);
    if (isink == NULL) {
        dev_err(&pdev->dev, "Unable to allocate private data\n");
        return -ENOMEM;
    }

    isink->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;
    }
    isink->reg = res->start;

    /* For current parts this is correct; probably need to revisit
     * in future.
     */
    snprintf(isink->name, sizeof(isink->name), "ISINK%d", id + 1);
    isink->desc.name = isink->name;
    isink->desc.id = id;
    isink->desc.ops = &wm831x_isink_ops;
    isink->desc.type = REGULATOR_CURRENT;
    isink->desc.owner = THIS_MODULE;

    config.dev = pdev->dev.parent;
    config.init_data = pdata->isink[id];
    config.driver_data = isink;

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

    irq = wm831x_irq(wm831x, platform_get_irq(pdev, 0));
    ret = request_threaded_irq(irq, NULL, wm831x_isink_irq,
                   IRQF_TRIGGER_RISING, isink->name, isink);
    if (ret != 0) {
        dev_err(&pdev->dev, "Failed to request ISINK IRQ %d: %d\n",
            irq, ret);
        goto err_regulator;
    }

    platform_set_drvdata(pdev, isink);

    return 0;

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

static __devexit int wm831x_isink_remove(struct platform_device *pdev)
{
    struct wm831x_isink *isink = platform_get_drvdata(pdev);

    platform_set_drvdata(pdev, NULL);

    free_irq(wm831x_irq(isink->wm831x, platform_get_irq(pdev, 0)), isink);

    regulator_unregister(isink->regulator);

    return 0;
}

static struct platform_driver wm831x_isink_driver = {
    .probe = wm831x_isink_probe,
    .remove = __devexit_p(wm831x_isink_remove),
    .driver     = {
        .name   = "wm831x-isink",
        .owner  = THIS_MODULE,
    },
};

static int __init wm831x_isink_init(void)
{
    int ret;
    ret = platform_driver_register(&wm831x_isink_driver);
    if (ret != 0)
        pr_err("Failed to register WM831x ISINK driver: %d\n", ret);

    return ret;
}
subsys_initcall(wm831x_isink_init);

static void __exit wm831x_isink_exit(void)
{
    platform_driver_unregister(&wm831x_isink_driver);
}
module_exit(wm831x_isink_exit);

/* Module information */
MODULE_AUTHOR("Mark Brown");
MODULE_DESCRIPTION("WM831x current sink driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-isink");