Blackfin RTC Driver: dont let RTC programming in bootloaders randomly cause ~5 second...

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rtc/rtc-bfin.c b/drivers/rtc/rtc-bfin.c
index 9d2da1cd7773a149ecee1a532a14733bb074ab16..34439ce3967e1844c552091fb72a0555b904644d 100644 (file)
--- a/drivers/rtc/rtc-bfin.c
+++ b/drivers/rtc/rtc-bfin.c
@@ -363,6 +363,7 @@ static int __devinit bfin_rtc_probe(struct platform_device *pdev)
        struct bfin_rtc *rtc;
        struct device *dev = &pdev->dev;
        int ret = 0;
+       unsigned long timeout;
 
        dev_dbg_stamp(dev);
 
@@ -377,6 +378,13 @@ static int __devinit bfin_rtc_probe(struct platform_device *pdev)
        ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_SHARED, pdev->name, dev);
        if (unlikely(ret))
                goto err;
+       /* sometimes the bootloader touched things, but the write complete was not
+        * enabled, so let's just do a quick timeout here since the IRQ will not fire ...
+        */
+       timeout = jiffies + HZ;
+       while (bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING)
+               if (time_after(jiffies, timeout))
+                       break;
        bfin_rtc_reset(dev, RTC_ISTAT_WRITE_COMPLETE);
        bfin_write_RTC_SWCNT(0);