blackfin RTC driver: drop PIE/stopwatch code since the hardware can only do a max of 1HZ and this same functionality is provided by UIE

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
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>

1 files changed, 14 insertions, 32 deletions

diff --git a/drivers/rtc/rtc-bfin.c b/drivers/rtc/rtc-bfin.c
index ceebce7e0a0f..a1af4c27939b 100644
--- a/drivers/rtc/rtc-bfin.c
+++ b/drivers/rtc/rtc-bfin.c
@@ -32,6 +32,15 @@
  * writes to clear status registers complete immediately.
  */
 
+/* It may seem odd that there is no SWCNT code in here (which would be exposed
+ * via the periodic interrupt event, or PIE).  Since the Blackfin RTC peripheral
+ * runs in units of seconds (N/HZ) but the Linux framework runs in units of HZ
+ * (2^N HZ), there is no point in keeping code that only provides 1 HZ PIEs.
+ * The same exact behavior can be accomplished by using the update interrupt
+ * event (UIE).  Maybe down the line the RTC peripheral will suck less in which
+ * case we can re-introduce PIE support.
+ */
+
 #include <linux/bcd.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
@@ -151,7 +160,6 @@ static void bfin_rtc_reset(struct device *dev, u16 rtc_ictl)
         bfin_rtc_sync_pending(dev);
         bfin_write_RTC_PREN(0x1);
         bfin_write_RTC_ICTL(rtc_ictl);
-        bfin_write_RTC_SWCNT(0);
         bfin_write_RTC_ALARM(0);
         bfin_write_RTC_ISTAT(0xFFFF);
         rtc->rtc_wrote_regs = 0;
@@ -194,14 +202,6 @@ static irqreturn_t bfin_rtc_interrupt(int irq, void *dev_id)
                 }
         }
 
-        if (rtc_ictl & RTC_ISTAT_STOPWATCH) {
-                if (rtc_istat & RTC_ISTAT_STOPWATCH) {
-                        bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH);
-                        events |= RTC_PF | RTC_IRQF;
-                        bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
-                }
-        }
-
         if (rtc_ictl & RTC_ISTAT_SEC) {
                 if (rtc_istat & RTC_ISTAT_SEC) {
                         bfin_write_RTC_ISTAT(RTC_ISTAT_SEC);
@@ -361,33 +361,14 @@ static int bfin_rtc_proc(struct device *dev, struct seq_file *seq)
         seq_printf(seq,
                 "alarm_IRQ\t: %s\n"
                 "wkalarm_IRQ\t: %s\n"
-                "seconds_IRQ\t: %s\n"
-                "periodic_IRQ\t: %s\n",
+                "seconds_IRQ\t: %s\n",
                 yesno(ictl & RTC_ISTAT_ALARM),
                 yesno(ictl & RTC_ISTAT_ALARM_DAY),
-                yesno(ictl & RTC_ISTAT_SEC),
-                yesno(ictl & RTC_ISTAT_STOPWATCH));
+                yesno(ictl & RTC_ISTAT_SEC));
         return 0;
 #undef yesno
 }
 
-static int bfin_irq_set_state(struct device *dev, int enabled)
-{
-        struct bfin_rtc *rtc = dev_get_drvdata(dev);
-
-        dev_dbg_stamp(dev);
-
-        bfin_rtc_sync_pending(dev);
-
-        if (enabled) {
-                bfin_rtc_int_set(RTC_ISTAT_STOPWATCH);
-                bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq);
-        } else
-                bfin_rtc_int_clear(~RTC_ISTAT_STOPWATCH);
-
-        return 0;
-}
-
 static struct rtc_class_ops bfin_rtc_ops = {
         .open          = bfin_rtc_open,
         .release       = bfin_rtc_release,
@@ -397,7 +378,6 @@ static struct rtc_class_ops bfin_rtc_ops = {
         .read_alarm    = bfin_rtc_read_alarm,
         .set_alarm     = bfin_rtc_set_alarm,
         .proc          = bfin_rtc_proc,
-        .irq_set_state = bfin_irq_set_state,
 };
 
 static int __devinit bfin_rtc_probe(struct platform_device *pdev)
@@ -416,7 +396,9 @@ static int __devinit bfin_rtc_probe(struct platform_device *pdev)
                 ret = PTR_ERR(rtc->rtc_dev);
                 goto err;
         }
-        rtc->rtc_dev->irq_freq = 1;
+
+        /* see comment at top of file about stopwatch/PIE */
+        bfin_write_RTC_SWCNT(0);
 
         platform_set_drvdata(pdev, rtc);