rtc-mpc5121.c

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/*
 * Real-time clock driver for MPC5121
 *
 * Copyright 2007, Domen Puncer <[email protected]>
 * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.
 * Copyright 2011, Dmitry Eremin-Solenikov
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/io.h>
#include <linux/slab.h>

struct mpc5121_rtc_regs {
    u8 set_time;        /* RTC + 0x00 */
    u8 hour_set;        /* RTC + 0x01 */
    u8 minute_set;      /* RTC + 0x02 */
    u8 second_set;      /* RTC + 0x03 */

    u8 set_date;        /* RTC + 0x04 */
    u8 month_set;       /* RTC + 0x05 */
    u8 weekday_set;     /* RTC + 0x06 */
    u8 date_set;        /* RTC + 0x07 */

    u8 write_sw;        /* RTC + 0x08 */
    u8 sw_set;      /* RTC + 0x09 */
    u16 year_set;       /* RTC + 0x0a */

    u8 alm_enable;      /* RTC + 0x0c */
    u8 alm_hour_set;    /* RTC + 0x0d */
    u8 alm_min_set;     /* RTC + 0x0e */
    u8 int_enable;      /* RTC + 0x0f */

    u8 reserved1;
    u8 hour;        /* RTC + 0x11 */
    u8 minute;      /* RTC + 0x12 */
    u8 second;      /* RTC + 0x13 */

    u8 month;       /* RTC + 0x14 */
    u8 wday_mday;       /* RTC + 0x15 */
    u16 year;       /* RTC + 0x16 */

    u8 int_alm;     /* RTC + 0x18 */
    u8 int_sw;      /* RTC + 0x19 */
    u8 alm_status;      /* RTC + 0x1a */
    u8 sw_minute;       /* RTC + 0x1b */

    u8 bus_error_1;     /* RTC + 0x1c */
    u8 int_day;     /* RTC + 0x1d */
    u8 int_min;     /* RTC + 0x1e */
    u8 int_sec;     /* RTC + 0x1f */

    /*
     * target_time:
     *  intended to be used for hibernation but hibernation
     *  does not work on silicon rev 1.5 so use it for non-volatile
     *  storage of offset between the actual_time register and linux
     *  time
     */
    u32 target_time;    /* RTC + 0x20 */
    /*
     * actual_time:
     *  readonly time since VBAT_RTC was last connected
     */
    u32 actual_time;    /* RTC + 0x24 */
    u32 keep_alive;     /* RTC + 0x28 */
};

struct mpc5121_rtc_data {
    unsigned irq;
    unsigned irq_periodic;
    struct mpc5121_rtc_regs __iomem *regs;
    struct rtc_device *rtc;
    struct rtc_wkalrm wkalarm;
};

/*
 * Update second/minute/hour registers.
 *
 * This is just so alarm will work.
 */
static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
                   struct rtc_time *tm)
{
    out_8(&regs->second_set, tm->tm_sec);
    out_8(&regs->minute_set, tm->tm_min);
    out_8(&regs->hour_set, tm->tm_hour);

    /* set time sequence */
    out_8(&regs->set_time, 0x1);
    out_8(&regs->set_time, 0x3);
    out_8(&regs->set_time, 0x1);
    out_8(&regs->set_time, 0x0);
}

static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
    unsigned long now;

    /*
     * linux time is actual_time plus the offset saved in target_time
     */
    now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);

    rtc_time_to_tm(now, tm);

    /*
     * update second minute hour registers
     * so alarms will work
     */
    mpc5121_rtc_update_smh(regs, tm);

    return rtc_valid_tm(tm);
}

static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
    int ret;
    unsigned long now;

    /*
     * The actual_time register is read only so we write the offset
     * between it and linux time to the target_time register.
     */
    ret = rtc_tm_to_time(tm, &now);
    if (ret == 0)
        out_be32(&regs->target_time, now - in_be32(&regs->actual_time));

    /*
     * update second minute hour registers
     * so alarms will work
     */
    mpc5121_rtc_update_smh(regs, tm);

    return 0;
}

static int mpc5200_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
    int tmp;

    tm->tm_sec = in_8(&regs->second);
    tm->tm_min = in_8(&regs->minute);

    /* 12 hour format? */
    if (in_8(&regs->hour) & 0x20)
        tm->tm_hour = (in_8(&regs->hour) >> 1) +
            (in_8(&regs->hour) & 1 ? 12 : 0);
    else
        tm->tm_hour = in_8(&regs->hour);

    tmp = in_8(&regs->wday_mday);
    tm->tm_mday = tmp & 0x1f;
    tm->tm_mon = in_8(&regs->month) - 1;
    tm->tm_year = in_be16(&regs->year) - 1900;
    tm->tm_wday = (tmp >> 5) % 7;
    tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
    tm->tm_isdst = 0;

    return 0;
}

static int mpc5200_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    mpc5121_rtc_update_smh(regs, tm);

    /* date */
    out_8(&regs->month_set, tm->tm_mon + 1);
    out_8(&regs->weekday_set, tm->tm_wday ? tm->tm_wday : 7);
    out_8(&regs->date_set, tm->tm_mday);
    out_be16(&regs->year_set, tm->tm_year + 1900);

    /* set date sequence */
    out_8(&regs->set_date, 0x1);
    out_8(&regs->set_date, 0x3);
    out_8(&regs->set_date, 0x1);
    out_8(&regs->set_date, 0x0);

    return 0;
}

static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    *alarm = rtc->wkalarm;

    alarm->pending = in_8(&regs->alm_status);

    return 0;
}

static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    /*
     * the alarm has no seconds so deal with it
     */
    if (alarm->time.tm_sec) {
        alarm->time.tm_sec = 0;
        alarm->time.tm_min++;
        if (alarm->time.tm_min >= 60) {
            alarm->time.tm_min = 0;
            alarm->time.tm_hour++;
            if (alarm->time.tm_hour >= 24)
                alarm->time.tm_hour = 0;
        }
    }

    alarm->time.tm_mday = -1;
    alarm->time.tm_mon = -1;
    alarm->time.tm_year = -1;

    out_8(&regs->alm_min_set, alarm->time.tm_min);
    out_8(&regs->alm_hour_set, alarm->time.tm_hour);

    out_8(&regs->alm_enable, alarm->enabled);

    rtc->wkalarm = *alarm;
    return 0;
}

static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    if (in_8(&regs->int_alm)) {
        /* acknowledge and clear status */
        out_8(&regs->int_alm, 1);
        out_8(&regs->alm_status, 1);

        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
        return IRQ_HANDLED;
    }

    return IRQ_NONE;
}

static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
        /* acknowledge */
        out_8(&regs->int_sec, 1);

        rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
        return IRQ_HANDLED;
    }

    return IRQ_NONE;
}

static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
                    unsigned int enabled)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
    int val;

    if (enabled)
        val = 1;
    else
        val = 0;

    out_8(&regs->alm_enable, val);
    rtc->wkalarm.enabled = val;

    return 0;
}

static const struct rtc_class_ops mpc5121_rtc_ops = {
    .read_time = mpc5121_rtc_read_time,
    .set_time = mpc5121_rtc_set_time,
    .read_alarm = mpc5121_rtc_read_alarm,
    .set_alarm = mpc5121_rtc_set_alarm,
    .alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
};

static const struct rtc_class_ops mpc5200_rtc_ops = {
    .read_time = mpc5200_rtc_read_time,
    .set_time = mpc5200_rtc_set_time,
    .read_alarm = mpc5121_rtc_read_alarm,
    .set_alarm = mpc5121_rtc_set_alarm,
    .alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
};

static int __devinit mpc5121_rtc_probe(struct platform_device *op)
{
    struct mpc5121_rtc_data *rtc;
    int err = 0;

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

    rtc->regs = of_iomap(op->dev.of_node, 0);
    if (!rtc->regs) {
        dev_err(&op->dev, "%s: couldn't map io space\n", __func__);
        err = -ENOSYS;
        goto out_free;
    }

    device_init_wakeup(&op->dev, 1);

    dev_set_drvdata(&op->dev, rtc);

    rtc->irq = irq_of_parse_and_map(op->dev.of_node, 1);
    err = request_irq(rtc->irq, mpc5121_rtc_handler, 0,
                        "mpc5121-rtc", &op->dev);
    if (err) {
        dev_err(&op->dev, "%s: could not request irq: %i\n",
                            __func__, rtc->irq);
        goto out_dispose;
    }

    rtc->irq_periodic = irq_of_parse_and_map(op->dev.of_node, 0);
    err = request_irq(rtc->irq_periodic, mpc5121_rtc_handler_upd,
                0, "mpc5121-rtc_upd", &op->dev);
    if (err) {
        dev_err(&op->dev, "%s: could not request irq: %i\n",
                        __func__, rtc->irq_periodic);
        goto out_dispose2;
    }

    if (of_device_is_compatible(op->dev.of_node, "fsl,mpc5121-rtc")) {
        u32 ka;
        ka = in_be32(&rtc->regs->keep_alive);
        if (ka & 0x02) {
            dev_warn(&op->dev,
                "mpc5121-rtc: Battery or oscillator failure!\n");
            out_be32(&rtc->regs->keep_alive, ka);
        }

        rtc->rtc = rtc_device_register("mpc5121-rtc", &op->dev,
                        &mpc5121_rtc_ops, THIS_MODULE);
    } else {
        rtc->rtc = rtc_device_register("mpc5200-rtc", &op->dev,
                        &mpc5200_rtc_ops, THIS_MODULE);
    }

    if (IS_ERR(rtc->rtc)) {
        err = PTR_ERR(rtc->rtc);
        goto out_free_irq;
    }
    rtc->rtc->uie_unsupported = 1;

    return 0;

out_free_irq:
    free_irq(rtc->irq_periodic, &op->dev);
out_dispose2:
    irq_dispose_mapping(rtc->irq_periodic);
    free_irq(rtc->irq, &op->dev);
out_dispose:
    irq_dispose_mapping(rtc->irq);
    iounmap(rtc->regs);
out_free:
    kfree(rtc);

    return err;
}

static int __devexit mpc5121_rtc_remove(struct platform_device *op)
{
    struct mpc5121_rtc_data *rtc = dev_get_drvdata(&op->dev);
    struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

    /* disable interrupt, so there are no nasty surprises */
    out_8(&regs->alm_enable, 0);
    out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);

    rtc_device_unregister(rtc->rtc);
    iounmap(rtc->regs);
    free_irq(rtc->irq, &op->dev);
    free_irq(rtc->irq_periodic, &op->dev);
    irq_dispose_mapping(rtc->irq);
    irq_dispose_mapping(rtc->irq_periodic);
    dev_set_drvdata(&op->dev, NULL);
    kfree(rtc);

    return 0;
}

static struct of_device_id mpc5121_rtc_match[] __devinitdata = {
    { .compatible = "fsl,mpc5121-rtc", },
    { .compatible = "fsl,mpc5200-rtc", },
    {},
};

static struct platform_driver mpc5121_rtc_driver = {
    .driver = {
        .name = "mpc5121-rtc",
        .owner = THIS_MODULE,
        .of_match_table = mpc5121_rtc_match,
    },
    .probe = mpc5121_rtc_probe,
    .remove = __devexit_p(mpc5121_rtc_remove),
};

module_platform_driver(mpc5121_rtc_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Rigby <[email protected]>");