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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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227 lines
4.9 KiB
C
227 lines
4.9 KiB
C
![]() |
/*
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* Dallas DS1216 RTC driver
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*
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* Copyright (c) 2007 Thomas Bogendoerfer
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*
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*/
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/platform_device.h>
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#include <linux/bcd.h>
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#define DRV_VERSION "0.1"
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struct ds1216_regs {
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u8 tsec;
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u8 sec;
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u8 min;
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u8 hour;
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u8 wday;
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u8 mday;
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u8 month;
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u8 year;
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};
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#define DS1216_HOUR_1224 (1 << 7)
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#define DS1216_HOUR_AMPM (1 << 5)
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struct ds1216_priv {
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struct rtc_device *rtc;
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void __iomem *ioaddr;
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size_t size;
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unsigned long baseaddr;
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};
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static const u8 magic[] = {
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0xc5, 0x3a, 0xa3, 0x5c, 0xc5, 0x3a, 0xa3, 0x5c
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};
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/*
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* Read the 64 bit we'd like to have - It a series
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* of 64 bits showing up in the LSB of the base register.
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*
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*/
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static void ds1216_read(u8 __iomem *ioaddr, u8 *buf)
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{
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unsigned char c;
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int i, j;
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for (i = 0; i < 8; i++) {
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c = 0;
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for (j = 0; j < 8; j++)
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c |= (readb(ioaddr) & 0x1) << j;
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buf[i] = c;
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}
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}
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static void ds1216_write(u8 __iomem *ioaddr, const u8 *buf)
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{
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unsigned char c;
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int i, j;
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for (i = 0; i < 8; i++) {
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c = buf[i];
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for (j = 0; j < 8; j++) {
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writeb(c, ioaddr);
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c = c >> 1;
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}
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}
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}
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static void ds1216_switch_ds_to_clock(u8 __iomem *ioaddr)
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{
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/* Reset magic pointer */
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readb(ioaddr);
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/* Write 64 bit magic to DS1216 */
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ds1216_write(ioaddr, magic);
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}
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static int ds1216_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 ds1216_priv *priv = platform_get_drvdata(pdev);
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struct ds1216_regs regs;
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ds1216_switch_ds_to_clock(priv->ioaddr);
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ds1216_read(priv->ioaddr, (u8 *)®s);
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tm->tm_sec = BCD2BIN(regs.sec);
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tm->tm_min = BCD2BIN(regs.min);
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if (regs.hour & DS1216_HOUR_1224) {
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/* AM/PM mode */
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tm->tm_hour = BCD2BIN(regs.hour & 0x1f);
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if (regs.hour & DS1216_HOUR_AMPM)
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tm->tm_hour += 12;
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} else
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tm->tm_hour = BCD2BIN(regs.hour & 0x3f);
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tm->tm_wday = (regs.wday & 7) - 1;
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tm->tm_mday = BCD2BIN(regs.mday & 0x3f);
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tm->tm_mon = BCD2BIN(regs.month & 0x1f);
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tm->tm_year = BCD2BIN(regs.year);
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if (tm->tm_year < 70)
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tm->tm_year += 100;
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return 0;
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}
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static int ds1216_rtc_set_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 ds1216_priv *priv = platform_get_drvdata(pdev);
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struct ds1216_regs regs;
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ds1216_switch_ds_to_clock(priv->ioaddr);
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ds1216_read(priv->ioaddr, (u8 *)®s);
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regs.tsec = 0; /* clear 0.1 and 0.01 seconds */
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regs.sec = BIN2BCD(tm->tm_sec);
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regs.min = BIN2BCD(tm->tm_min);
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regs.hour &= DS1216_HOUR_1224;
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if (regs.hour && tm->tm_hour > 12) {
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regs.hour |= DS1216_HOUR_AMPM;
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tm->tm_hour -= 12;
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}
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regs.hour |= BIN2BCD(tm->tm_hour);
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regs.wday &= ~7;
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regs.wday |= tm->tm_wday;
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regs.mday = BIN2BCD(tm->tm_mday);
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regs.month = BIN2BCD(tm->tm_mon);
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regs.year = BIN2BCD(tm->tm_year % 100);
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ds1216_switch_ds_to_clock(priv->ioaddr);
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ds1216_write(priv->ioaddr, (u8 *)®s);
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return 0;
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}
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static const struct rtc_class_ops ds1216_rtc_ops = {
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.read_time = ds1216_rtc_read_time,
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.set_time = ds1216_rtc_set_time,
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};
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static int __devinit ds1216_rtc_probe(struct platform_device *pdev)
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{
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struct rtc_device *rtc;
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struct resource *res;
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struct ds1216_priv *priv;
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int ret = 0;
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u8 dummy[8];
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res)
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return -ENODEV;
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priv = kzalloc(sizeof *priv, GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->size = res->end - res->start + 1;
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if (!request_mem_region(res->start, priv->size, pdev->name)) {
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ret = -EBUSY;
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goto out;
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}
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priv->baseaddr = res->start;
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priv->ioaddr = ioremap(priv->baseaddr, priv->size);
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if (!priv->ioaddr) {
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ret = -ENOMEM;
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goto out;
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}
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rtc = rtc_device_register("ds1216", &pdev->dev,
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&ds1216_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtc)) {
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ret = PTR_ERR(rtc);
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goto out;
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}
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priv->rtc = rtc;
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platform_set_drvdata(pdev, priv);
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/* dummy read to get clock into a known state */
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ds1216_read(priv->ioaddr, dummy);
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return 0;
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out:
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if (priv->rtc)
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rtc_device_unregister(priv->rtc);
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if (priv->ioaddr)
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iounmap(priv->ioaddr);
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if (priv->baseaddr)
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release_mem_region(priv->baseaddr, priv->size);
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kfree(priv);
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return ret;
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}
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static int __devexit ds1216_rtc_remove(struct platform_device *pdev)
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{
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struct ds1216_priv *priv = platform_get_drvdata(pdev);
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rtc_device_unregister(priv->rtc);
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iounmap(priv->ioaddr);
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release_mem_region(priv->baseaddr, priv->size);
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kfree(priv);
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return 0;
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}
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static struct platform_driver ds1216_rtc_platform_driver = {
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.driver = {
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.name = "rtc-ds1216",
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.owner = THIS_MODULE,
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},
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.probe = ds1216_rtc_probe,
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.remove = __devexit_p(ds1216_rtc_remove),
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};
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static int __init ds1216_rtc_init(void)
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{
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return platform_driver_register(&ds1216_rtc_platform_driver);
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}
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static void __exit ds1216_rtc_exit(void)
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{
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platform_driver_unregister(&ds1216_rtc_platform_driver);
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}
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MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
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MODULE_DESCRIPTION("DS1216 RTC driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION(DRV_VERSION);
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module_init(ds1216_rtc_init);
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module_exit(ds1216_rtc_exit);
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