Blackfin RTC driver: convert sync wait to use the irq write complete notice
- thus clearing out the need for spin locks - add a small optimization for reading of the rtc field Signed-off-by: Mike Frysinger <michael.frysinger@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com> Acked-by: Alessandro Zummo <alessandro.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>hifive-unleashed-5.1
Mike Frysinger
Linus Torvalds
parent
48c1a56b4b
commit
095b9d546f
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@ -1,6 +1,6 @@
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/*
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* Blackfin On-Chip Real Time Clock Driver
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* Supports BF53[123]/BF53[467]/BF54[2489]
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* Supports BF52[257]/BF53[123]/BF53[467]/BF54[24789]
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*
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* Copyright 2004-2007 Analog Devices Inc.
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*
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@ -32,16 +32,16 @@
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* writes to clear status registers complete immediately.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/bcd.h>
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#include <linux/rtc.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/seq_file.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#include <linux/seq_file.h>
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#include <asm/blackfin.h>
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@ -50,7 +50,7 @@
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struct bfin_rtc {
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struct rtc_device *rtc_dev;
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struct rtc_time rtc_alarm;
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spinlock_t lock;
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u16 rtc_wrote_regs;
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};
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/* Bit values for the ISTAT / ICTL registers */
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@ -96,7 +96,10 @@ static inline void rtc_bfin_to_tm(u32 rtc_bfin, struct rtc_time *tm)
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rtc_time_to_tm(rtc_bfin_to_time(rtc_bfin), tm);
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}
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/* Wait for the previous write to a RTC register to complete.
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/**
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* bfin_rtc_sync_pending - make sure pending writes have complete
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*
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* Wait for the previous write to a RTC register to complete.
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* Unfortunately, we can't sleep here as that introduces a race condition when
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* turning on interrupt events. Consider this:
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* - process sets alarm
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@ -117,64 +120,102 @@ static inline void rtc_bfin_to_tm(u32 rtc_bfin, struct rtc_time *tm)
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* inc rate for all RTC registers from 1HZ to 32.768kHZ ...
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* - use the write complete IRQ
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*/
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static void rtc_bfin_sync_pending(void)
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/*
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static void bfin_rtc_sync_pending_polled(void)
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{
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while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE)) {
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while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE))
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if (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING))
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break;
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}
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bfin_write_RTC_ISTAT(RTC_ISTAT_WRITE_COMPLETE);
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}
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*/
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static DECLARE_COMPLETION(bfin_write_complete);
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static void bfin_rtc_sync_pending(struct device *dev)
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{
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dev_dbg_stamp(dev);
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while (bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING)
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wait_for_completion_timeout(&bfin_write_complete, HZ * 5);
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dev_dbg_stamp(dev);
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}
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static void rtc_bfin_reset(struct device *dev)
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/**
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* bfin_rtc_reset - set RTC to sane/known state
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*
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* Initialize the RTC. Enable pre-scaler to scale RTC clock
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* to 1Hz and clear interrupt/status registers.
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*/
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static void bfin_rtc_reset(struct device *dev)
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{
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struct bfin_rtc *rtc = dev_get_drvdata(dev);
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/* Initialize the RTC. Enable pre-scaler to scale RTC clock
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* to 1Hz and clear interrupt/status registers. */
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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dev_dbg_stamp(dev);
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bfin_rtc_sync_pending(dev);
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bfin_write_RTC_PREN(0x1);
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bfin_write_RTC_ICTL(0);
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bfin_write_RTC_ICTL(RTC_ISTAT_WRITE_COMPLETE);
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bfin_write_RTC_SWCNT(0);
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bfin_write_RTC_ALARM(0);
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bfin_write_RTC_ISTAT(0xFFFF);
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spin_unlock_irq(&rtc->lock);
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rtc->rtc_wrote_regs = 0;
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}
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/**
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* bfin_rtc_interrupt - handle interrupt from RTC
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*
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* Since we handle all RTC events here, we have to make sure the requested
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* interrupt is enabled (in RTC_ICTL) as the event status register (RTC_ISTAT)
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* always gets updated regardless of the interrupt being enabled. So when one
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* even we care about (e.g. stopwatch) goes off, we don't want to turn around
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* and say that other events have happened as well (e.g. second). We do not
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* have to worry about pending writes to the RTC_ICTL register as interrupts
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* only fire if they are enabled in the RTC_ICTL register.
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*/
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static irqreturn_t bfin_rtc_interrupt(int irq, void *dev_id)
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{
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struct device *dev = dev_id;
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struct bfin_rtc *rtc = dev_get_drvdata(dev);
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unsigned long events = 0;
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u16 rtc_istat;
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bool write_complete = false;
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u16 rtc_istat, rtc_ictl;
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_istat = bfin_read_RTC_ISTAT();
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rtc_ictl = bfin_read_RTC_ICTL();
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if (rtc_istat & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY);
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events |= RTC_AF | RTC_IRQF;
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if (rtc_istat & RTC_ISTAT_WRITE_COMPLETE) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_WRITE_COMPLETE);
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write_complete = true;
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complete(&bfin_write_complete);
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}
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if (rtc_istat & RTC_ISTAT_STOPWATCH) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
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events |= RTC_PF | RTC_IRQF;
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bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
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if (rtc_ictl & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
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if (rtc_istat & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY);
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events |= RTC_AF | RTC_IRQF;
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}
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}
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if (rtc_istat & RTC_ISTAT_SEC) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
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events |= RTC_UF | RTC_IRQF;
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if (rtc_ictl & RTC_ISTAT_STOPWATCH) {
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if (rtc_istat & RTC_ISTAT_STOPWATCH) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
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events |= RTC_PF | RTC_IRQF;
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bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
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}
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}
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rtc_update_irq(rtc->rtc_dev, 1, events);
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if (rtc_ictl & RTC_ISTAT_SEC) {
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if (rtc_istat & RTC_ISTAT_SEC) {
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bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
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events |= RTC_UF | RTC_IRQF;
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}
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}
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spin_unlock_irq(&rtc->lock);
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if (events)
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rtc_update_irq(rtc->rtc_dev, 1, events);
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return IRQ_HANDLED;
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if (write_complete || events)
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return IRQ_HANDLED;
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else
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return IRQ_NONE;
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}
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static int bfin_rtc_open(struct device *dev)
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@ -183,13 +224,9 @@ static int bfin_rtc_open(struct device *dev)
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dev_dbg_stamp(dev);
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ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_DISABLED, "rtc-bfin", dev);
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if (unlikely(ret)) {
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dev_err(dev, "request RTC IRQ failed with %d\n", ret);
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return ret;
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}
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rtc_bfin_reset(dev);
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ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_SHARED, to_platform_device(dev)->name, dev);
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if (!ret)
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bfin_rtc_reset(dev);
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return ret;
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}
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@ -197,93 +234,70 @@ static int bfin_rtc_open(struct device *dev)
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static void bfin_rtc_release(struct device *dev)
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{
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dev_dbg_stamp(dev);
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rtc_bfin_reset(dev);
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bfin_rtc_reset(dev);
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free_irq(IRQ_RTC, dev);
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}
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static void bfin_rtc_int_set(struct bfin_rtc *rtc, u16 rtc_int)
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{
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bfin_write_RTC_ISTAT(rtc_int);
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | rtc_int);
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}
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static void bfin_rtc_int_clear(struct bfin_rtc *rtc, u16 rtc_int)
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{
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & rtc_int);
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}
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static void bfin_rtc_int_set_alarm(struct bfin_rtc *rtc)
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{
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/* Blackfin has different bits for whether the alarm is
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* more than 24 hours away.
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*/
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bfin_rtc_int_set(rtc, (rtc->rtc_alarm.tm_yday == -1 ? RTC_ISTAT_ALARM : RTC_ISTAT_ALARM_DAY));
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}
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static int bfin_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
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{
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struct bfin_rtc *rtc = dev_get_drvdata(dev);
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int ret = 0;
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dev_dbg_stamp(dev);
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bfin_rtc_sync_pending(dev);
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switch (cmd) {
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case RTC_PIE_ON:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
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bfin_rtc_int_set(rtc, RTC_ISTAT_STOPWATCH);
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bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | RTC_ISTAT_STOPWATCH);
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spin_unlock_irq(&rtc->lock);
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return 0;
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break;
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case RTC_PIE_OFF:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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bfin_write_RTC_SWCNT(0);
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~RTC_ISTAT_STOPWATCH);
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spin_unlock_irq(&rtc->lock);
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return 0;
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bfin_rtc_int_clear(rtc, ~RTC_ISTAT_STOPWATCH);
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break;
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case RTC_UIE_ON:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | RTC_ISTAT_SEC);
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spin_unlock_irq(&rtc->lock);
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return 0;
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bfin_rtc_int_set(rtc, RTC_ISTAT_SEC);
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break;
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case RTC_UIE_OFF:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~RTC_ISTAT_SEC);
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spin_unlock_irq(&rtc->lock);
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return 0;
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case RTC_AIE_ON: {
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unsigned long rtc_alarm;
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u16 which_alarm;
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int ret = 0;
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bfin_rtc_int_clear(rtc, ~RTC_ISTAT_SEC);
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break;
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case RTC_AIE_ON:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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if (rtc->rtc_alarm.tm_yday == -1) {
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struct rtc_time now;
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rtc_bfin_to_tm(bfin_read_RTC_STAT(), &now);
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now.tm_sec = rtc->rtc_alarm.tm_sec;
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now.tm_min = rtc->rtc_alarm.tm_min;
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now.tm_hour = rtc->rtc_alarm.tm_hour;
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ret = rtc_tm_to_time(&now, &rtc_alarm);
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which_alarm = RTC_ISTAT_ALARM;
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} else {
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ret = rtc_tm_to_time(&rtc->rtc_alarm, &rtc_alarm);
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which_alarm = RTC_ISTAT_ALARM_DAY;
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}
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if (ret == 0) {
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bfin_write_RTC_ISTAT(which_alarm);
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bfin_write_RTC_ALARM(rtc_time_to_bfin(rtc_alarm));
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | which_alarm);
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}
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spin_unlock_irq(&rtc->lock);
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return ret;
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}
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bfin_rtc_int_set_alarm(rtc);
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break;
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case RTC_AIE_OFF:
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY));
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spin_unlock_irq(&rtc->lock);
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return 0;
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bfin_rtc_int_clear(rtc, ~(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY));
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break;
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default:
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dev_dbg_stamp(dev);
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ret = -ENOIOCTLCMD;
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}
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return -ENOIOCTLCMD;
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return ret;
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}
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static int bfin_rtc_read_time(struct device *dev, struct rtc_time *tm)
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@ -292,10 +306,10 @@ static int bfin_rtc_read_time(struct device *dev, struct rtc_time *tm)
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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rtc_bfin_sync_pending();
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if (rtc->rtc_wrote_regs & 0x1)
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bfin_rtc_sync_pending(dev);
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rtc_bfin_to_tm(bfin_read_RTC_STAT(), tm);
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spin_unlock_irq(&rtc->lock);
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return 0;
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}
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@ -308,16 +322,14 @@ static int bfin_rtc_set_time(struct device *dev, struct rtc_time *tm)
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dev_dbg_stamp(dev);
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spin_lock_irq(&rtc->lock);
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ret = rtc_tm_to_time(tm, &now);
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if (ret == 0) {
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rtc_bfin_sync_pending();
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if (rtc->rtc_wrote_regs & 0x1)
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bfin_rtc_sync_pending(dev);
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bfin_write_RTC_STAT(rtc_time_to_bfin(now));
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rtc->rtc_wrote_regs = 0x1;
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}
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spin_unlock_irq(&rtc->lock);
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return ret;
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}
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@ -326,6 +338,7 @@ static int bfin_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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struct bfin_rtc *rtc = dev_get_drvdata(dev);
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dev_dbg_stamp(dev);
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alrm->time = rtc->rtc_alarm;
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bfin_rtc_sync_pending(dev);
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alrm->enabled = !!(bfin_read_RTC_ICTL() & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY));
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return 0;
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}
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@ -333,8 +346,20 @@ static int bfin_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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static int bfin_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
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{
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struct bfin_rtc *rtc = dev_get_drvdata(dev);
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unsigned long rtc_alarm;
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dev_dbg_stamp(dev);
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if (rtc_tm_to_time(&alrm->time, &rtc_alarm))
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return -EINVAL;
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rtc->rtc_alarm = alrm->time;
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bfin_rtc_sync_pending(dev);
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bfin_write_RTC_ALARM(rtc_time_to_bfin(rtc_alarm));
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if (alrm->enabled)
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bfin_rtc_int_set_alarm(rtc);
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return 0;
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}
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@ -393,8 +418,6 @@ static int __devinit bfin_rtc_probe(struct platform_device *pdev)
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if (unlikely(!rtc))
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return -ENOMEM;
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spin_lock_init(&rtc->lock);
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rtc->rtc_dev = rtc_device_register(pdev->name, &pdev->dev, &bfin_rtc_ops, THIS_MODULE);
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if (unlikely(IS_ERR(rtc))) {
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ret = PTR_ERR(rtc->rtc_dev);
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