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![John Stultz](/assets/img/avatar_default.png)
Commit f44f7f96a2
("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.
This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.
The solution is to ensure the drvdata is initialized prior to registering
the rtc device.
CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: John Stultz <john.stultz@linaro.org>
221 lines
5.5 KiB
C
221 lines
5.5 KiB
C
/*
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* pcap rtc code for Motorola EZX phones
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*
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* Copyright (c) 2008 guiming zhuo <gmzhuo@gmail.com>
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* Copyright (c) 2009 Daniel Ribeiro <drwyrm@gmail.com>
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*
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* Based on Motorola's rtc.c Copyright (c) 2003-2005 Motorola
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/mfd/ezx-pcap.h>
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#include <linux/rtc.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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struct pcap_rtc {
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struct pcap_chip *pcap;
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struct rtc_device *rtc;
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};
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static irqreturn_t pcap_rtc_irq(int irq, void *_pcap_rtc)
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{
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struct pcap_rtc *pcap_rtc = _pcap_rtc;
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unsigned long rtc_events;
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if (irq == pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ))
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rtc_events = RTC_IRQF | RTC_UF;
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else if (irq == pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA))
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rtc_events = RTC_IRQF | RTC_AF;
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else
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rtc_events = 0;
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rtc_update_irq(pcap_rtc->rtc, 1, rtc_events);
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return IRQ_HANDLED;
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}
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static int pcap_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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struct rtc_time *tm = &alrm->time;
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unsigned long secs;
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u32 tod; /* time of day, seconds since midnight */
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u32 days; /* days since 1/1/1970 */
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ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_TODA, &tod);
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secs = tod & PCAP_RTC_TOD_MASK;
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ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_DAYA, &days);
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secs += (days & PCAP_RTC_DAY_MASK) * SEC_PER_DAY;
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rtc_time_to_tm(secs, tm);
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return 0;
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}
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static int pcap_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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struct rtc_time *tm = &alrm->time;
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unsigned long secs;
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u32 tod, days;
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rtc_tm_to_time(tm, &secs);
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tod = secs % SEC_PER_DAY;
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ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_TODA, tod);
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days = secs / SEC_PER_DAY;
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ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_DAYA, days);
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return 0;
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}
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static int pcap_rtc_read_time(struct device *dev, struct rtc_time *tm)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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unsigned long secs;
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u32 tod, days;
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ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_TOD, &tod);
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secs = tod & PCAP_RTC_TOD_MASK;
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ezx_pcap_read(pcap_rtc->pcap, PCAP_REG_RTC_DAY, &days);
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secs += (days & PCAP_RTC_DAY_MASK) * SEC_PER_DAY;
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rtc_time_to_tm(secs, tm);
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return rtc_valid_tm(tm);
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}
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static int pcap_rtc_set_mmss(struct device *dev, unsigned long secs)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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u32 tod, days;
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tod = secs % SEC_PER_DAY;
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ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_TOD, tod);
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days = secs / SEC_PER_DAY;
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ezx_pcap_write(pcap_rtc->pcap, PCAP_REG_RTC_DAY, days);
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return 0;
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}
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static int pcap_rtc_irq_enable(struct device *dev, int pirq, unsigned int en)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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if (en)
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enable_irq(pcap_to_irq(pcap_rtc->pcap, pirq));
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else
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disable_irq(pcap_to_irq(pcap_rtc->pcap, pirq));
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return 0;
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}
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static int pcap_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
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{
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return pcap_rtc_irq_enable(dev, PCAP_IRQ_TODA, en);
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}
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static const struct rtc_class_ops pcap_rtc_ops = {
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.read_time = pcap_rtc_read_time,
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.read_alarm = pcap_rtc_read_alarm,
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.set_alarm = pcap_rtc_set_alarm,
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.set_mmss = pcap_rtc_set_mmss,
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.alarm_irq_enable = pcap_rtc_alarm_irq_enable,
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};
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static int __devinit pcap_rtc_probe(struct platform_device *pdev)
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{
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struct pcap_rtc *pcap_rtc;
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int timer_irq, alarm_irq;
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int err = -ENOMEM;
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pcap_rtc = kmalloc(sizeof(struct pcap_rtc), GFP_KERNEL);
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if (!pcap_rtc)
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return err;
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pcap_rtc->pcap = dev_get_drvdata(pdev->dev.parent);
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platform_set_drvdata(pdev, pcap_rtc);
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pcap_rtc->rtc = rtc_device_register("pcap", &pdev->dev,
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&pcap_rtc_ops, THIS_MODULE);
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if (IS_ERR(pcap_rtc->rtc)) {
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err = PTR_ERR(pcap_rtc->rtc);
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goto fail_rtc;
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}
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timer_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ);
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alarm_irq = pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA);
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err = request_irq(timer_irq, pcap_rtc_irq, 0, "RTC Timer", pcap_rtc);
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if (err)
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goto fail_timer;
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err = request_irq(alarm_irq, pcap_rtc_irq, 0, "RTC Alarm", pcap_rtc);
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if (err)
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goto fail_alarm;
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return 0;
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fail_alarm:
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free_irq(timer_irq, pcap_rtc);
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fail_timer:
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rtc_device_unregister(pcap_rtc->rtc);
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fail_rtc:
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platform_set_drvdata(pdev, NULL);
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kfree(pcap_rtc);
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return err;
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}
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static int __devexit pcap_rtc_remove(struct platform_device *pdev)
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{
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struct pcap_rtc *pcap_rtc = platform_get_drvdata(pdev);
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free_irq(pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_1HZ), pcap_rtc);
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free_irq(pcap_to_irq(pcap_rtc->pcap, PCAP_IRQ_TODA), pcap_rtc);
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rtc_device_unregister(pcap_rtc->rtc);
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kfree(pcap_rtc);
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return 0;
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}
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static struct platform_driver pcap_rtc_driver = {
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.remove = __devexit_p(pcap_rtc_remove),
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.driver = {
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.name = "pcap-rtc",
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.owner = THIS_MODULE,
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},
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};
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static int __init rtc_pcap_init(void)
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{
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return platform_driver_probe(&pcap_rtc_driver, pcap_rtc_probe);
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}
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static void __exit rtc_pcap_exit(void)
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{
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platform_driver_unregister(&pcap_rtc_driver);
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}
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module_init(rtc_pcap_init);
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module_exit(rtc_pcap_exit);
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MODULE_DESCRIPTION("Motorola pcap rtc driver");
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MODULE_AUTHOR("guiming zhuo <gmzhuo@gmail.com>");
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MODULE_LICENSE("GPL");
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