rtc-nuc900.c

Go to the documentation of this file.

/*
 * Copyright (c) 2008-2009 Nuvoton technology corporation.
 *
 * Wan ZongShun <[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;version 2 of the License.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/bcd.h>

/* RTC Control Registers */
#define REG_RTC_INIR        0x00
#define REG_RTC_AER     0x04
#define REG_RTC_FCR     0x08
#define REG_RTC_TLR     0x0C
#define REG_RTC_CLR     0x10
#define REG_RTC_TSSR        0x14
#define REG_RTC_DWR     0x18
#define REG_RTC_TAR     0x1C
#define REG_RTC_CAR     0x20
#define REG_RTC_LIR     0x24
#define REG_RTC_RIER        0x28
#define REG_RTC_RIIR        0x2C
#define REG_RTC_TTR     0x30

#define RTCSET          0x01
#define AERRWENB        0x10000
#define INIRRESET       0xa5eb1357
#define AERPOWERON      0xA965
#define AERPOWEROFF     0x0000
#define LEAPYEAR        0x0001
#define TICKENB         0x80
#define TICKINTENB      0x0002
#define ALARMINTENB     0x0001
#define MODE24          0x0001

struct nuc900_rtc {
    int         irq_num;
    void __iomem        *rtc_reg;
    struct rtc_device   *rtcdev;
};

struct nuc900_bcd_time {
    int bcd_sec;
    int bcd_min;
    int bcd_hour;
    int bcd_mday;
    int bcd_mon;
    int bcd_year;
};

static irqreturn_t nuc900_rtc_interrupt(int irq, void *_rtc)
{
    struct nuc900_rtc *rtc = _rtc;
    unsigned long events = 0, rtc_irq;

    rtc_irq = __raw_readl(rtc->rtc_reg + REG_RTC_RIIR);

    if (rtc_irq & ALARMINTENB) {
        rtc_irq &= ~ALARMINTENB;
        __raw_writel(rtc_irq, rtc->rtc_reg + REG_RTC_RIIR);
        events |= RTC_AF | RTC_IRQF;
    }

    if (rtc_irq & TICKINTENB) {
        rtc_irq &= ~TICKINTENB;
        __raw_writel(rtc_irq, rtc->rtc_reg + REG_RTC_RIIR);
        events |= RTC_UF | RTC_IRQF;
    }

    rtc_update_irq(rtc->rtcdev, 1, events);

    return IRQ_HANDLED;
}

static int *check_rtc_access_enable(struct nuc900_rtc *nuc900_rtc)
{
    unsigned int timeout = 0x1000;
    __raw_writel(INIRRESET, nuc900_rtc->rtc_reg + REG_RTC_INIR);

    mdelay(10);

    __raw_writel(AERPOWERON, nuc900_rtc->rtc_reg + REG_RTC_AER);

    while (!(__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_AER) & AERRWENB)
                                && timeout--)
        mdelay(1);

    if (!timeout)
        return ERR_PTR(-EPERM);

    return 0;
}

static int nuc900_rtc_bcd2bin(unsigned int timereg,
                unsigned int calreg, struct rtc_time *tm)
{
    tm->tm_mday = bcd2bin(calreg >> 0);
    tm->tm_mon  = bcd2bin(calreg >> 8);
    tm->tm_year = bcd2bin(calreg >> 16) + 100;

    tm->tm_sec  = bcd2bin(timereg >> 0);
    tm->tm_min  = bcd2bin(timereg >> 8);
    tm->tm_hour = bcd2bin(timereg >> 16);

    return rtc_valid_tm(tm);
}

static void nuc900_rtc_bin2bcd(struct device *dev, struct rtc_time *settm,
                        struct nuc900_bcd_time *gettm)
{
    gettm->bcd_mday = bin2bcd(settm->tm_mday) << 0;
    gettm->bcd_mon  = bin2bcd(settm->tm_mon) << 8;

    if (settm->tm_year < 100) {
        dev_warn(dev, "The year will be between 1970-1999, right?\n");
        gettm->bcd_year = bin2bcd(settm->tm_year) << 16;
    } else {
        gettm->bcd_year = bin2bcd(settm->tm_year - 100) << 16;
    }

    gettm->bcd_sec  = bin2bcd(settm->tm_sec) << 0;
    gettm->bcd_min  = bin2bcd(settm->tm_min) << 8;
    gettm->bcd_hour = bin2bcd(settm->tm_hour) << 16;
}

static int nuc900_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
    struct nuc900_rtc *rtc = dev_get_drvdata(dev);

    if (enabled)
        __raw_writel(__raw_readl(rtc->rtc_reg + REG_RTC_RIER)|
                (ALARMINTENB), rtc->rtc_reg + REG_RTC_RIER);
    else
        __raw_writel(__raw_readl(rtc->rtc_reg + REG_RTC_RIER)&
                (~ALARMINTENB), rtc->rtc_reg + REG_RTC_RIER);

    return 0;
}

static int nuc900_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    struct nuc900_rtc *rtc = dev_get_drvdata(dev);
    unsigned int timeval, clrval;

    timeval = __raw_readl(rtc->rtc_reg + REG_RTC_TLR);
    clrval  = __raw_readl(rtc->rtc_reg + REG_RTC_CLR);

    return nuc900_rtc_bcd2bin(timeval, clrval, tm);
}

static int nuc900_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    struct nuc900_rtc *rtc = dev_get_drvdata(dev);
    struct nuc900_bcd_time gettm;
    unsigned long val;
    int *err;

    nuc900_rtc_bin2bcd(dev, tm, &gettm);

    err = check_rtc_access_enable(rtc);
    if (IS_ERR(err))
        return PTR_ERR(err);

    val = gettm.bcd_mday | gettm.bcd_mon | gettm.bcd_year;
    __raw_writel(val, rtc->rtc_reg + REG_RTC_CLR);

    val = gettm.bcd_sec | gettm.bcd_min | gettm.bcd_hour;
    __raw_writel(val, rtc->rtc_reg + REG_RTC_TLR);

    return 0;
}

static int nuc900_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct nuc900_rtc *rtc = dev_get_drvdata(dev);
    unsigned int timeval, carval;

    timeval = __raw_readl(rtc->rtc_reg + REG_RTC_TAR);
    carval  = __raw_readl(rtc->rtc_reg + REG_RTC_CAR);

    return nuc900_rtc_bcd2bin(timeval, carval, &alrm->time);
}

static int nuc900_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct nuc900_rtc *rtc = dev_get_drvdata(dev);
    struct nuc900_bcd_time tm;
    unsigned long val;
    int *err;

    nuc900_rtc_bin2bcd(dev, &alrm->time, &tm);

    err = check_rtc_access_enable(rtc);
    if (IS_ERR(err))
        return PTR_ERR(err);

    val = tm.bcd_mday | tm.bcd_mon | tm.bcd_year;
    __raw_writel(val, rtc->rtc_reg + REG_RTC_CAR);

    val = tm.bcd_sec | tm.bcd_min | tm.bcd_hour;
    __raw_writel(val, rtc->rtc_reg + REG_RTC_TAR);

    return 0;
}

static struct rtc_class_ops nuc900_rtc_ops = {
    .read_time = nuc900_rtc_read_time,
    .set_time = nuc900_rtc_set_time,
    .read_alarm = nuc900_rtc_read_alarm,
    .set_alarm = nuc900_rtc_set_alarm,
    .alarm_irq_enable = nuc900_alarm_irq_enable,
};

static int __devinit nuc900_rtc_probe(struct platform_device *pdev)
{
    struct resource *res;
    struct nuc900_rtc *nuc900_rtc;
    int err = 0;

    nuc900_rtc = kzalloc(sizeof(struct nuc900_rtc), GFP_KERNEL);
    if (!nuc900_rtc) {
        dev_err(&pdev->dev, "kzalloc nuc900_rtc failed\n");
        return -ENOMEM;
    }
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "platform_get_resource failed\n");
        err = -ENXIO;
        goto fail1;
    }

    if (!request_mem_region(res->start, resource_size(res),
                pdev->name)) {
        dev_err(&pdev->dev, "request_mem_region failed\n");
        err = -EBUSY;
        goto fail1;
    }

    nuc900_rtc->rtc_reg = ioremap(res->start, resource_size(res));
    if (!nuc900_rtc->rtc_reg) {
        dev_err(&pdev->dev, "ioremap rtc_reg failed\n");
        err = -ENOMEM;
        goto fail2;
    }

    platform_set_drvdata(pdev, nuc900_rtc);

    nuc900_rtc->rtcdev = rtc_device_register(pdev->name, &pdev->dev,
                        &nuc900_rtc_ops, THIS_MODULE);
    if (IS_ERR(nuc900_rtc->rtcdev)) {
        dev_err(&pdev->dev, "rtc device register failed\n");
        err = PTR_ERR(nuc900_rtc->rtcdev);
        goto fail3;
    }

    __raw_writel(__raw_readl(nuc900_rtc->rtc_reg + REG_RTC_TSSR) | MODE24,
                    nuc900_rtc->rtc_reg + REG_RTC_TSSR);

    nuc900_rtc->irq_num = platform_get_irq(pdev, 0);
    if (request_irq(nuc900_rtc->irq_num, nuc900_rtc_interrupt,
                0, "nuc900rtc", nuc900_rtc)) {
        dev_err(&pdev->dev, "NUC900 RTC request irq failed\n");
        err = -EBUSY;
        goto fail4;
    }

    return 0;

fail4:  rtc_device_unregister(nuc900_rtc->rtcdev);
fail3:  iounmap(nuc900_rtc->rtc_reg);
fail2:  release_mem_region(res->start, resource_size(res));
fail1:  kfree(nuc900_rtc);
    return err;
}

static int __devexit nuc900_rtc_remove(struct platform_device *pdev)
{
    struct nuc900_rtc *nuc900_rtc = platform_get_drvdata(pdev);
    struct resource *res;

    free_irq(nuc900_rtc->irq_num, nuc900_rtc);
    rtc_device_unregister(nuc900_rtc->rtcdev);
    iounmap(nuc900_rtc->rtc_reg);

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    release_mem_region(res->start, resource_size(res));

    kfree(nuc900_rtc);

    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver nuc900_rtc_driver = {
    .remove     = __devexit_p(nuc900_rtc_remove),
    .driver     = {
        .name   = "nuc900-rtc",
        .owner  = THIS_MODULE,
    },
};

static int __init nuc900_rtc_init(void)
{
    return platform_driver_probe(&nuc900_rtc_driver, nuc900_rtc_probe);
}

static void __exit nuc900_rtc_exit(void)
{
    platform_driver_unregister(&nuc900_rtc_driver);
}

module_init(nuc900_rtc_init);
module_exit(nuc900_rtc_exit);

MODULE_AUTHOR("Wan ZongShun <[email protected]>");
MODULE_DESCRIPTION("nuc910/nuc920 RTC driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:nuc900-rtc");