rtc-mc13xxx.c

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/*
 * Real Time Clock driver for Freescale MC13XXX PMIC
 *
 * (C) 2009 Sascha Hauer, Pengutronix
 * (C) 2009 Uwe Kleine-Koenig, Pengutronix
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/mfd/mc13xxx.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/rtc.h>

#define DRIVER_NAME "mc13xxx-rtc"

#define MC13XXX_RTCTOD  20
#define MC13XXX_RTCTODA 21
#define MC13XXX_RTCDAY  22
#define MC13XXX_RTCDAYA 23

struct mc13xxx_rtc {
    struct rtc_device *rtc;
    struct mc13xxx *mc13xxx;
    int valid;
};

static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
        unsigned int enabled, int irq)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    int (*func)(struct mc13xxx *mc13xxx, int irq);

    if (!priv->valid)
        return -ENODATA;

    func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
    return func(priv->mc13xxx, irq);
}

static int mc13xxx_rtc_irq_enable(struct device *dev,
        unsigned int enabled, int irq)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    int ret;

    mc13xxx_lock(priv->mc13xxx);

    ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, irq);

    mc13xxx_unlock(priv->mc13xxx);

    return ret;
}

static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    unsigned int seconds, days1, days2;
    unsigned long s1970;
    int ret;

    mc13xxx_lock(priv->mc13xxx);

    if (!priv->valid) {
        ret = -ENODATA;
        goto out;
    }

    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
out:
    mc13xxx_unlock(priv->mc13xxx);

    if (ret)
        return ret;

    if (days2 == days1 + 1) {
        if (seconds >= 86400 / 2)
            days2 = days1;
        else
            days1 = days2;
    }

    if (days1 != days2)
        return -EIO;

    s1970 = days1 * 86400 + seconds;

    rtc_time_to_tm(s1970, tm);

    return rtc_valid_tm(tm);
}

static int mc13xxx_rtc_set_mmss(struct device *dev, unsigned long secs)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    unsigned int seconds, days;
    unsigned int alarmseconds;
    int ret;

    seconds = secs % 86400;
    days = secs / 86400;

    mc13xxx_lock(priv->mc13xxx);

    /*
     * temporarily invalidate alarm to prevent triggering it when the day is
     * already updated while the time isn't yet.
     */
    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
    if (unlikely(ret))
        goto out;

    if (alarmseconds < 86400) {
        ret = mc13xxx_reg_write(priv->mc13xxx,
                MC13XXX_RTCTODA, 0x1ffff);
        if (unlikely(ret))
            goto out;
    }

    /*
     * write seconds=0 to prevent a day switch between writing days
     * and seconds below
     */
    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
    if (unlikely(ret))
        goto out;

    /* restore alarm */
    if (alarmseconds < 86400) {
        ret = mc13xxx_reg_write(priv->mc13xxx,
                MC13XXX_RTCTODA, alarmseconds);
        if (unlikely(ret))
            goto out;
    }

    ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
out:
    priv->valid = !ret;

    mc13xxx_unlock(priv->mc13xxx);

    return ret;
}

static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    unsigned seconds, days;
    unsigned long s1970;
    int enabled, pending;
    int ret;

    mc13xxx_lock(priv->mc13xxx);

    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
    if (unlikely(ret))
        goto out;
    if (seconds >= 86400) {
        ret = -ENODATA;
        goto out;
    }

    ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
            &enabled, &pending);

out:
    mc13xxx_unlock(priv->mc13xxx);

    if (ret)
        return ret;

    alarm->enabled = enabled;
    alarm->pending = pending;

    s1970 = days * 86400 + seconds;

    rtc_time_to_tm(s1970, &alarm->time);
    dev_dbg(dev, "%s: %lu\n", __func__, s1970);

    return 0;
}

static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
    struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
    unsigned long s1970;
    unsigned seconds, days;
    int ret;

    mc13xxx_lock(priv->mc13xxx);

    /* disable alarm to prevent false triggering */
    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
    if (unlikely(ret))
        goto out;

    ret = rtc_tm_to_time(&alarm->time, &s1970);
    if (unlikely(ret))
        goto out;

    dev_dbg(dev, "%s: o%2.s %lu\n", __func__, alarm->enabled ? "n" : "ff",
            s1970);

    ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
            MC13XXX_IRQ_TODA);
    if (unlikely(ret))
        goto out;

    seconds = s1970 % 86400;
    days = s1970 / 86400;

    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
    if (unlikely(ret))
        goto out;

    ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);

out:
    mc13xxx_unlock(priv->mc13xxx);

    return ret;
}

static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
{
    struct mc13xxx_rtc *priv = dev;
    struct mc13xxx *mc13xxx = priv->mc13xxx;

    dev_dbg(&priv->rtc->dev, "Alarm\n");

    rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);

    mc13xxx_irq_ack(mc13xxx, irq);

    return IRQ_HANDLED;
}

static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
{
    struct mc13xxx_rtc *priv = dev;
    struct mc13xxx *mc13xxx = priv->mc13xxx;

    dev_dbg(&priv->rtc->dev, "1HZ\n");

    rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);

    mc13xxx_irq_ack(mc13xxx, irq);

    return IRQ_HANDLED;
}

static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
        unsigned int enabled)
{
    return mc13xxx_rtc_irq_enable(dev, enabled, MC13XXX_IRQ_TODA);
}

static const struct rtc_class_ops mc13xxx_rtc_ops = {
    .read_time = mc13xxx_rtc_read_time,
    .set_mmss = mc13xxx_rtc_set_mmss,
    .read_alarm = mc13xxx_rtc_read_alarm,
    .set_alarm = mc13xxx_rtc_set_alarm,
    .alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
};

static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
{
    struct mc13xxx_rtc *priv = dev;
    struct mc13xxx *mc13xxx = priv->mc13xxx;

    dev_dbg(&priv->rtc->dev, "RTCRST\n");
    priv->valid = 0;

    mc13xxx_irq_mask(mc13xxx, irq);

    return IRQ_HANDLED;
}

static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
{
    int ret;
    struct mc13xxx_rtc *priv;
    struct mc13xxx *mc13xxx;
    int rtcrst_pending;

    priv = kzalloc(sizeof(*priv), GFP_KERNEL);
    if (!priv)
        return -ENOMEM;

    mc13xxx = dev_get_drvdata(pdev->dev.parent);
    priv->mc13xxx = mc13xxx;

    platform_set_drvdata(pdev, priv);

    mc13xxx_lock(mc13xxx);

    ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
            mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
    if (ret)
        goto err_reset_irq_request;

    ret = mc13xxx_irq_status(mc13xxx, MC13XXX_IRQ_RTCRST,
            NULL, &rtcrst_pending);
    if (ret)
        goto err_reset_irq_status;

    priv->valid = !rtcrst_pending;

    ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_1HZ,
            mc13xxx_rtc_update_handler, DRIVER_NAME, priv);
    if (ret)
        goto err_update_irq_request;

    ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
            mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
    if (ret)
        goto err_alarm_irq_request;

    mc13xxx_unlock(mc13xxx);

    priv->rtc = rtc_device_register(pdev->name,
            &pdev->dev, &mc13xxx_rtc_ops, THIS_MODULE);
    if (IS_ERR(priv->rtc)) {
        ret = PTR_ERR(priv->rtc);

        mc13xxx_lock(mc13xxx);

        mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
err_alarm_irq_request:

        mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
err_update_irq_request:

err_reset_irq_status:

        mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
err_reset_irq_request:

        mc13xxx_unlock(mc13xxx);

        platform_set_drvdata(pdev, NULL);
        kfree(priv);
    }

    return ret;
}

static int __exit mc13xxx_rtc_remove(struct platform_device *pdev)
{
    struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);

    mc13xxx_lock(priv->mc13xxx);

    rtc_device_unregister(priv->rtc);

    mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
    mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_1HZ, priv);
    mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);

    mc13xxx_unlock(priv->mc13xxx);

    platform_set_drvdata(pdev, NULL);

    kfree(priv);

    return 0;
}

static const struct platform_device_id mc13xxx_rtc_idtable[] = {
    {
        .name = "mc13783-rtc",
    }, {
        .name = "mc13892-rtc",
    }, {
        .name = "mc34708-rtc",
    },
    { /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);

static struct platform_driver mc13xxx_rtc_driver = {
    .id_table = mc13xxx_rtc_idtable,
    .remove = __exit_p(mc13xxx_rtc_remove),
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
    },
};

static int __init mc13xxx_rtc_init(void)
{
    return platform_driver_probe(&mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
}
module_init(mc13xxx_rtc_init);

static void __exit mc13xxx_rtc_exit(void)
{
    platform_driver_unregister(&mc13xxx_rtc_driver);
}
module_exit(mc13xxx_rtc_exit);

MODULE_AUTHOR("Sascha Hauer <[email protected]>");
MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
MODULE_LICENSE("GPL v2");