rtc-at91rm9200.c

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/*
 *  Real Time Clock interface for Linux on Atmel AT91RM9200
 *
 *  Copyright (C) 2002 Rick Bronson
 *
 *  Converted to RTC class model by Andrew Victor
 *
 *  Ported to Linux 2.6 by Steven Scholz
 *  Based on s3c2410-rtc.c Simtec Electronics
 *
 *  Based on sa1100-rtc.c by Nils Faerber
 *  Based on rtc.c by Paul Gortmaker
 *
 *  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/kernel.h>
#include <linux/platform_device.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/completion.h>
#include <linux/io.h>

#include <asm/uaccess.h>

#include <mach/at91_rtc.h>

#define at91_rtc_read(field) \
    __raw_readl(at91_rtc_regs + field)
#define at91_rtc_write(field, val) \
    __raw_writel((val), at91_rtc_regs + field)

#define AT91_RTC_EPOCH      1900UL  /* just like arch/arm/common/rtctime.c */

static DECLARE_COMPLETION(at91_rtc_updated);
static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
static void __iomem *at91_rtc_regs;
static int irq;

/*
 * Decode time/date into rtc_time structure
 */
static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
                struct rtc_time *tm)
{
    unsigned int time, date;

    /* must read twice in case it changes */
    do {
        time = at91_rtc_read(timereg);
        date = at91_rtc_read(calreg);
    } while ((time != at91_rtc_read(timereg)) ||
            (date != at91_rtc_read(calreg)));

    tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
    tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
    tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);

    /*
     * The Calendar Alarm register does not have a field for
     * the year - so these will return an invalid value.  When an
     * alarm is set, at91_alarm_year will store the current year.
     */
    tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
    tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */

    tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
    tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
    tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
}

/*
 * Read current time and date in RTC
 */
static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
    at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
    tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
    tm->tm_year = tm->tm_year - 1900;

    pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
        1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    return 0;
}

/*
 * Set current time and date in RTC
 */
static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
{
    unsigned long cr;

    pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
        1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    /* Stop Time/Calendar from counting */
    cr = at91_rtc_read(AT91_RTC_CR);
    at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);

    at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
    wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
    at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);

    at91_rtc_write(AT91_RTC_TIMR,
              bin2bcd(tm->tm_sec) << 0
            | bin2bcd(tm->tm_min) << 8
            | bin2bcd(tm->tm_hour) << 16);

    at91_rtc_write(AT91_RTC_CALR,
              bin2bcd((tm->tm_year + 1900) / 100)   /* century */
            | bin2bcd(tm->tm_year % 100) << 8   /* year */
            | bin2bcd(tm->tm_mon + 1) << 16     /* tm_mon starts at zero */
            | bin2bcd(tm->tm_wday + 1) << 21    /* day of the week [0-6], Sunday=0 */
            | bin2bcd(tm->tm_mday) << 24);

    /* Restart Time/Calendar */
    cr = at91_rtc_read(AT91_RTC_CR);
    at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));

    return 0;
}

/*
 * Read alarm time and date in RTC
 */
static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct rtc_time *tm = &alrm->time;

    at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
    tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
    tm->tm_year = at91_alarm_year - 1900;

    alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
            ? 1 : 0;

    pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
        1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    return 0;
}

/*
 * Set alarm time and date in RTC
 */
static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct rtc_time tm;

    at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);

    at91_alarm_year = tm.tm_year;

    tm.tm_hour = alrm->time.tm_hour;
    tm.tm_min = alrm->time.tm_min;
    tm.tm_sec = alrm->time.tm_sec;

    at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
    at91_rtc_write(AT91_RTC_TIMALR,
          bin2bcd(tm.tm_sec) << 0
        | bin2bcd(tm.tm_min) << 8
        | bin2bcd(tm.tm_hour) << 16
        | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
    at91_rtc_write(AT91_RTC_CALALR,
          bin2bcd(tm.tm_mon + 1) << 16      /* tm_mon starts at zero */
        | bin2bcd(tm.tm_mday) << 24
        | AT91_RTC_DATEEN | AT91_RTC_MTHEN);

    if (alrm->enabled) {
        at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
        at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
    }

    pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
        at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
        tm.tm_min, tm.tm_sec);

    return 0;
}

static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    pr_debug("%s(): cmd=%08x\n", __func__, enabled);

    if (enabled) {
        at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
        at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
    } else
        at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);

    return 0;
}
/*
 * Provide additional RTC information in /proc/driver/rtc
 */
static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
{
    unsigned long imr = at91_rtc_read(AT91_RTC_IMR);

    seq_printf(seq, "update_IRQ\t: %s\n",
            (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
    seq_printf(seq, "periodic_IRQ\t: %s\n",
            (imr & AT91_RTC_SECEV) ? "yes" : "no");

    return 0;
}

/*
 * IRQ handler for the RTC
 */
static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
{
    struct platform_device *pdev = dev_id;
    struct rtc_device *rtc = platform_get_drvdata(pdev);
    unsigned int rtsr;
    unsigned long events = 0;

    rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
    if (rtsr) {     /* this interrupt is shared!  Is it ours? */
        if (rtsr & AT91_RTC_ALARM)
            events |= (RTC_AF | RTC_IRQF);
        if (rtsr & AT91_RTC_SECEV)
            events |= (RTC_UF | RTC_IRQF);
        if (rtsr & AT91_RTC_ACKUPD)
            complete(&at91_rtc_updated);

        at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */

        rtc_update_irq(rtc, 1, events);

        pr_debug("%s(): num=%ld, events=0x%02lx\n", __func__,
            events >> 8, events & 0x000000FF);

        return IRQ_HANDLED;
    }
    return IRQ_NONE;        /* not handled */
}

static const struct rtc_class_ops at91_rtc_ops = {
    .read_time  = at91_rtc_readtime,
    .set_time   = at91_rtc_settime,
    .read_alarm = at91_rtc_readalarm,
    .set_alarm  = at91_rtc_setalarm,
    .proc       = at91_rtc_proc,
    .alarm_irq_enable = at91_rtc_alarm_irq_enable,
};

/*
 * Initialize and install RTC driver
 */
static int __init at91_rtc_probe(struct platform_device *pdev)
{
    struct rtc_device *rtc;
    struct resource *regs;
    int ret = 0;

    regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!regs) {
        dev_err(&pdev->dev, "no mmio resource defined\n");
        return -ENXIO;
    }

    irq = platform_get_irq(pdev, 0);
    if (irq < 0) {
        dev_err(&pdev->dev, "no irq resource defined\n");
        return -ENXIO;
    }

    at91_rtc_regs = ioremap(regs->start, resource_size(regs));
    if (!at91_rtc_regs) {
        dev_err(&pdev->dev, "failed to map registers, aborting.\n");
        return -ENOMEM;
    }

    at91_rtc_write(AT91_RTC_CR, 0);
    at91_rtc_write(AT91_RTC_MR, 0);     /* 24 hour mode */

    /* Disable all interrupts */
    at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
                    AT91_RTC_SECEV | AT91_RTC_TIMEV |
                    AT91_RTC_CALEV);

    ret = request_irq(irq, at91_rtc_interrupt,
                IRQF_SHARED,
                "at91_rtc", pdev);
    if (ret) {
        printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
                irq);
        return ret;
    }

    /* cpu init code should really have flagged this device as
     * being wake-capable; if it didn't, do that here.
     */
    if (!device_can_wakeup(&pdev->dev))
        device_init_wakeup(&pdev->dev, 1);

    rtc = rtc_device_register(pdev->name, &pdev->dev,
                &at91_rtc_ops, THIS_MODULE);
    if (IS_ERR(rtc)) {
        free_irq(irq, pdev);
        return PTR_ERR(rtc);
    }
    platform_set_drvdata(pdev, rtc);

    printk(KERN_INFO "AT91 Real Time Clock driver.\n");
    return 0;
}

/*
 * Disable and remove the RTC driver
 */
static int __exit at91_rtc_remove(struct platform_device *pdev)
{
    struct rtc_device *rtc = platform_get_drvdata(pdev);

    /* Disable all interrupts */
    at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
                    AT91_RTC_SECEV | AT91_RTC_TIMEV |
                    AT91_RTC_CALEV);
    free_irq(irq, pdev);

    rtc_device_unregister(rtc);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

#ifdef CONFIG_PM

/* AT91RM9200 RTC Power management control */

static u32 at91_rtc_imr;

static int at91_rtc_suspend(struct device *dev)
{
    /* this IRQ is shared with DBGU and other hardware which isn't
     * necessarily doing PM like we are...
     */
    at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
            & (AT91_RTC_ALARM|AT91_RTC_SECEV);
    if (at91_rtc_imr) {
        if (device_may_wakeup(dev))
            enable_irq_wake(irq);
        else
            at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
    }
    return 0;
}

static int at91_rtc_resume(struct device *dev)
{
    if (at91_rtc_imr) {
        if (device_may_wakeup(dev))
            disable_irq_wake(irq);
        else
            at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
    }
    return 0;
}

static const struct dev_pm_ops at91_rtc_pm = {
    .suspend =  at91_rtc_suspend,
    .resume =   at91_rtc_resume,
};

#define at91_rtc_pm_ptr &at91_rtc_pm

#else
#define at91_rtc_pm_ptr NULL
#endif

static struct platform_driver at91_rtc_driver = {
    .remove     = __exit_p(at91_rtc_remove),
    .driver     = {
        .name   = "at91_rtc",
        .owner  = THIS_MODULE,
        .pm = at91_rtc_pm_ptr,
    },
};

static int __init at91_rtc_init(void)
{
    return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
}

static void __exit at91_rtc_exit(void)
{
    platform_driver_unregister(&at91_rtc_driver);
}

module_init(at91_rtc_init);
module_exit(at91_rtc_exit);

MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:at91_rtc");