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* drivers/rtc/rtc-vt8500.c
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* Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/bcd.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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* Register definitions
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#define VT8500_RTC_TS 0x00 /* Time set */
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#define VT8500_RTC_DS 0x04 /* Date set */
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#define VT8500_RTC_AS 0x08 /* Alarm set */
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#define VT8500_RTC_CR 0x0c /* Control */
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#define VT8500_RTC_TR 0x10 /* Time read */
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#define VT8500_RTC_DR 0x14 /* Date read */
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#define VT8500_RTC_WS 0x18 /* Write status */
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#define VT8500_RTC_CL 0x20 /* Calibration */
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#define VT8500_RTC_IS 0x24 /* Interrupt status */
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#define VT8500_RTC_ST 0x28 /* Status */
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#define INVALID_TIME_BIT (1 << 31)
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#define DATE_CENTURY_S 19
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#define DATE_YEAR_S 11
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#define DATE_YEAR_MASK (0xff << DATE_YEAR_S)
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#define DATE_MONTH_S 6
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#define DATE_MONTH_MASK (0x1f << DATE_MONTH_S)
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#define DATE_DAY_MASK 0x3f
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#define TIME_DOW_MASK (0x07 << TIME_DOW_S)
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#define TIME_HOUR_S 14
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#define TIME_HOUR_MASK (0x3f << TIME_HOUR_S)
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#define TIME_MIN_MASK (0x7f << TIME_MIN_S)
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#define TIME_SEC_MASK 0x7f
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#define ALARM_DAY_S 20
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#define ALARM_DAY_MASK (0x3f << ALARM_DAY_S)
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#define ALARM_DAY_BIT (1 << 29)
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#define ALARM_HOUR_BIT (1 << 28)
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#define ALARM_MIN_BIT (1 << 27)
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#define ALARM_SEC_BIT (1 << 26)
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#define ALARM_ENABLE_MASK (ALARM_DAY_BIT \
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#define VT8500_RTC_CR_ENABLE (1 << 0) /* Enable RTC */
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#define VT8500_RTC_CR_24H (1 << 1) /* 24h time format */
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#define VT8500_RTC_CR_SM_ENABLE (1 << 2) /* Enable periodic irqs */
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#define VT8500_RTC_CR_SM_SEC (1 << 3) /* 0: 1Hz/60, 1: 1Hz */
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#define VT8500_RTC_CR_CALIB (1 << 4) /* Enable calibration */
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void __iomem *regbase;
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struct rtc_device *rtc;
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spinlock_t lock; /* Protects this structure */
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static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
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struct vt8500_rtc *vt8500_rtc = dev_id;
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unsigned long events = 0;
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spin_lock(&vt8500_rtc->lock);
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/* clear interrupt sources */
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isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
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writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
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spin_unlock(&vt8500_rtc->lock);
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events |= RTC_AF | RTC_IRQF;
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rtc_update_irq(vt8500_rtc->rtc, 1, events);
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static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
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struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
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date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
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time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
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tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
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tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
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tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
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tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
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tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S);
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tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
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+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
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tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
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static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
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struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
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if (tm->tm_year < 100) {
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dev_warn(dev, "Only years 2000-2199 are supported by the "
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writel((bin2bcd(tm->tm_year - 100) << DATE_YEAR_S)
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| (bin2bcd(tm->tm_mon) << DATE_MONTH_S)
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| (bin2bcd(tm->tm_mday)),
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vt8500_rtc->regbase + VT8500_RTC_DS);
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writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
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| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
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| (bin2bcd(tm->tm_min) << TIME_MIN_S)
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| (bin2bcd(tm->tm_sec)),
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vt8500_rtc->regbase + VT8500_RTC_TS);
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static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
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alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
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isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
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alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
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alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
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alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
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alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
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alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
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alrm->pending = (isr & 1) ? 1 : 0;
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return rtc_valid_tm(&alrm->time);
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static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
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writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
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| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
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| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
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| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
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| (bin2bcd(alrm->time.tm_sec)),
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vt8500_rtc->regbase + VT8500_RTC_AS);
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static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
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struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
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unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
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tmp |= ALARM_ENABLE_MASK;
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tmp &= ~ALARM_ENABLE_MASK;
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writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
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static const struct rtc_class_ops vt8500_rtc_ops = {
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.read_time = vt8500_rtc_read_time,
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.set_time = vt8500_rtc_set_time,
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.read_alarm = vt8500_rtc_read_alarm,
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.set_alarm = vt8500_rtc_set_alarm,
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.alarm_irq_enable = vt8500_alarm_irq_enable,
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static int __devinit vt8500_rtc_probe(struct platform_device *pdev)
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struct vt8500_rtc *vt8500_rtc;
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vt8500_rtc = kzalloc(sizeof(struct vt8500_rtc), GFP_KERNEL);
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spin_lock_init(&vt8500_rtc->lock);
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platform_set_drvdata(pdev, vt8500_rtc);
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vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!vt8500_rtc->res) {
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dev_err(&pdev->dev, "No I/O memory resource defined\n");
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vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
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if (vt8500_rtc->irq_alarm < 0) {
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dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
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vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,
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resource_size(vt8500_rtc->res),
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if (vt8500_rtc->res == NULL) {
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dev_err(&pdev->dev, "failed to request I/O memory\n");
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vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,
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resource_size(vt8500_rtc->res));
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if (!vt8500_rtc->regbase) {
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dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
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/* Enable RTC and set it to 24-hour mode */
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writel(VT8500_RTC_CR_ENABLE | VT8500_RTC_CR_24H,
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vt8500_rtc->regbase + VT8500_RTC_CR);
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vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
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&vt8500_rtc_ops, THIS_MODULE);
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if (IS_ERR(vt8500_rtc->rtc)) {
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ret = PTR_ERR(vt8500_rtc->rtc);
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"Failed to register RTC device -> %d\n", ret);
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ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,
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"rtc alarm", vt8500_rtc);
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dev_err(&pdev->dev, "can't get irq %i, err %d\n",
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vt8500_rtc->irq_alarm, ret);
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rtc_device_unregister(vt8500_rtc->rtc);
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iounmap(vt8500_rtc->regbase);
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release_mem_region(vt8500_rtc->res->start,
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resource_size(vt8500_rtc->res));
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static int __devexit vt8500_rtc_remove(struct platform_device *pdev)
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struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
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free_irq(vt8500_rtc->irq_alarm, vt8500_rtc);
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rtc_device_unregister(vt8500_rtc->rtc);
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/* Disable alarm matching */
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writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
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iounmap(vt8500_rtc->regbase);
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release_mem_region(vt8500_rtc->res->start,
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resource_size(vt8500_rtc->res));
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platform_set_drvdata(pdev, NULL);
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static struct platform_driver vt8500_rtc_driver = {
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.probe = vt8500_rtc_probe,
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.remove = __devexit_p(vt8500_rtc_remove),
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.name = "vt8500-rtc",
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.owner = THIS_MODULE,
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static int __init vt8500_rtc_init(void)
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return platform_driver_register(&vt8500_rtc_driver);
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module_init(vt8500_rtc_init);
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static void __exit vt8500_rtc_exit(void)
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platform_driver_unregister(&vt8500_rtc_driver);
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module_exit(vt8500_rtc_exit);
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MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
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MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:vt8500-rtc");