6 files changed, 152 insertions, 15 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index cdd97192dc69..4941cade319f 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -97,6 +97,18 @@ config RTC_INTF_DEV
 
           If unsure, say Y.
 
+config RTC_INTF_DEV_UIE_EMUL
+        bool "RTC UIE emulation on dev interface"
+        depends on RTC_INTF_DEV
+        help
+          Provides an emulation for RTC_UIE if the underlying rtc chip
+          driver does not expose RTC_UIE ioctls. Those requests generate
+          once-per-second update interrupts, used for synchronization.
+
+          The emulation code will read the time from the hardware
+          clock several times per second, please enable this option
+          only if you know that you really need it.
+
 config RTC_DRV_TEST
         tristate "Test driver/device"
         help
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index a0c01967244d..cb2f0728fd70 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -209,9 +209,8 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
         }
 
         if (err)
-                return err;
-
-        if (!rtc->ops)
+                /* nothing */;
+        else if (!rtc->ops)
                 err = -ENODEV;
         else if (!rtc->ops->alarm_irq_enable)
                 err = -EINVAL;
@@ -229,6 +228,12 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
         if (err)
                 return err;
 
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        if (enabled == 0 && rtc->uie_irq_active) {
+                mutex_unlock(&rtc->ops_lock);
+                return rtc_dev_update_irq_enable_emul(rtc, 0);
+        }
+#endif
         /* make sure we're changing state */
         if (rtc->uie_rtctimer.enabled == enabled)
                 goto out;
@@ -248,6 +253,16 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
 
 out:
         mutex_unlock(&rtc->ops_lock);
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        /*
+         * Enable emulation if the driver did not provide
+         * the update_irq_enable function pointer or if returned
+         * -EINVAL to signal that it has been configured without
+         * interrupts or that are not available at the moment.
+         */
+        if (err == -EINVAL)
+                err = rtc_dev_update_irq_enable_emul(rtc, enabled);
+#endif
         return err;
 
 }
@@ -263,7 +278,7 @@ EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
  *
  * Triggers the registered irq_task function callback.
  */
-static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
+void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
 {
         unsigned long flags;
 
diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index c36749e4c926..5469c52cba3d 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -309,7 +309,7 @@ static const struct rtc_class_ops at91_rtc_ops = {
         .read_alarm     = at91_rtc_readalarm,
         .set_alarm      = at91_rtc_setalarm,
         .proc           = at91_rtc_proc,
-        .alarm_irq_enabled = at91_rtc_alarm_irq_enable,
+        .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 };
 
 /*
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 37c3cc1b3dd5..d0e06edb14c5 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -46,6 +46,105 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
         return err;
 }
 
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+/*
+ * Routine to poll RTC seconds field for change as often as possible,
+ * after first RTC_UIE use timer to reduce polling
+ */
+static void rtc_uie_task(struct work_struct *work)
+{
+        struct rtc_device *rtc =
+                container_of(work, struct rtc_device, uie_task);
+        struct rtc_time tm;
+        int num = 0;
+        int err;
+
+        err = rtc_read_time(rtc, &tm);
+
+        spin_lock_irq(&rtc->irq_lock);
+        if (rtc->stop_uie_polling || err) {
+                rtc->uie_task_active = 0;
+        } else if (rtc->oldsecs != tm.tm_sec) {
+                num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
+                rtc->oldsecs = tm.tm_sec;
+                rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
+                rtc->uie_timer_active = 1;
+                rtc->uie_task_active = 0;
+                add_timer(&rtc->uie_timer);
+        } else if (schedule_work(&rtc->uie_task) == 0) {
+                rtc->uie_task_active = 0;
+        }
+        spin_unlock_irq(&rtc->irq_lock);
+        if (num)
+                rtc_handle_legacy_irq(rtc, num, RTC_UF);
+}
+static void rtc_uie_timer(unsigned long data)
+{
+        struct rtc_device *rtc = (struct rtc_device *)data;
+        unsigned long flags;
+
+        spin_lock_irqsave(&rtc->irq_lock, flags);
+        rtc->uie_timer_active = 0;
+        rtc->uie_task_active = 1;
+        if ((schedule_work(&rtc->uie_task) == 0))
+                rtc->uie_task_active = 0;
+        spin_unlock_irqrestore(&rtc->irq_lock, flags);
+}
+
+static int clear_uie(struct rtc_device *rtc)
+{
+        spin_lock_irq(&rtc->irq_lock);
+        if (rtc->uie_irq_active) {
+                rtc->stop_uie_polling = 1;
+                if (rtc->uie_timer_active) {
+                        spin_unlock_irq(&rtc->irq_lock);
+                        del_timer_sync(&rtc->uie_timer);
+                        spin_lock_irq(&rtc->irq_lock);
+                        rtc->uie_timer_active = 0;
+                }
+                if (rtc->uie_task_active) {
+                        spin_unlock_irq(&rtc->irq_lock);
+                        flush_scheduled_work();
+                        spin_lock_irq(&rtc->irq_lock);
+                }
+                rtc->uie_irq_active = 0;
+        }
+        spin_unlock_irq(&rtc->irq_lock);
+        return 0;
+}
+
+static int set_uie(struct rtc_device *rtc)
+{
+        struct rtc_time tm;
+        int err;
+
+        err = rtc_read_time(rtc, &tm);
+        if (err)
+                return err;
+        spin_lock_irq(&rtc->irq_lock);
+        if (!rtc->uie_irq_active) {
+                rtc->uie_irq_active = 1;
+                rtc->stop_uie_polling = 0;
+                rtc->oldsecs = tm.tm_sec;
+                rtc->uie_task_active = 1;
+                if (schedule_work(&rtc->uie_task) == 0)
+                        rtc->uie_task_active = 0;
+        }
+        rtc->irq_data = 0;
+        spin_unlock_irq(&rtc->irq_lock);
+        return 0;
+}
+
+int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled)
+{
+        if (enabled)
+                return set_uie(rtc);
+        else
+                return clear_uie(rtc);
+}
+EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul);
+
+#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
 
 static ssize_t
 rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
@@ -387,6 +486,11 @@ void rtc_dev_prepare(struct rtc_device *rtc)
 
         rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id);
 
+#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
+        INIT_WORK(&rtc->uie_task, rtc_uie_task);
+        setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
+#endif
+
         cdev_init(&rtc->char_dev, &rtc_dev_fops);
         rtc->char_dev.owner = rtc->owner;
 }
diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
index 23a9ee19764c..950735415a7c 100644
--- a/drivers/rtc/rtc-ds3232.c
+++ b/drivers/rtc/rtc-ds3232.c
@@ -1,7 +1,7 @@
 /*
  * RTC client/driver for the Maxim/Dallas DS3232 Real-Time Clock over I2C
  *
- * Copyright (C) 2009-2010 Freescale Semiconductor.
+ * Copyright (C) 2009-2011 Freescale Semiconductor.
  * Author: Jack Lan <jack.lan@freescale.com>
  *
  * This program is free software; you can redistribute  it and/or modify it
@@ -141,9 +141,11 @@ static int ds3232_read_time(struct device *dev, struct rtc_time *time)
                 time->tm_hour = bcd2bin(hour);
         }
 
-        time->tm_wday = bcd2bin(week);
+        /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
+        time->tm_wday = bcd2bin(week) - 1;
         time->tm_mday = bcd2bin(day);
-        time->tm_mon = bcd2bin(month & 0x7F);
+        /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
+        time->tm_mon = bcd2bin(month & 0x7F) - 1;
         if (century)
                 add_century = 100;
 
@@ -162,9 +164,11 @@ static int ds3232_set_time(struct device *dev, struct rtc_time *time)
         buf[0] = bin2bcd(time->tm_sec);
         buf[1] = bin2bcd(time->tm_min);
         buf[2] = bin2bcd(time->tm_hour);
-        buf[3] = bin2bcd(time->tm_wday); /* Day of the week */
+        /* Day of the week in linux range is 0~6 while 1~7 in RTC chip */
+        buf[3] = bin2bcd(time->tm_wday + 1);
         buf[4] = bin2bcd(time->tm_mday); /* Date */
-        buf[5] = bin2bcd(time->tm_mon);
+        /* linux tm_mon range:0~11, while month range is 1~12 in RTC chip */
+        buf[5] = bin2bcd(time->tm_mon + 1);
         if (time->tm_year >= 100) {
                 buf[5] |= 0x80;
                 buf[6] = bin2bcd(time->tm_year - 100);
diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index cf953ecbfca9..b80fa2882408 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -77,18 +77,20 @@ static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
 }
 
 /* Update control registers */
-static void s3c_rtc_setaie(int to)
+static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 {
         unsigned int tmp;
 
-        pr_debug("%s: aie=%d\n", __func__, to);
+        pr_debug("%s: aie=%d\n", __func__, enabled);
 
         tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
 
-        if (to)
+        if (enabled)
                 tmp |= S3C2410_RTCALM_ALMEN;
 
         writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);
+
+        return 0;
 }
 
 static int s3c_rtc_setpie(struct device *dev, int enabled)
@@ -308,7 +310,7 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
         writeb(alrm_en, base + S3C2410_RTCALM);
 
-        s3c_rtc_setaie(alrm->enabled);
+        s3c_rtc_setaie(dev, alrm->enabled);
 
         return 0;
 }
@@ -440,7 +442,7 @@ static int __devexit s3c_rtc_remove(struct platform_device *dev)
         rtc_device_unregister(rtc);
 
         s3c_rtc_setpie(&dev->dev, 0);
-        s3c_rtc_setaie(0);
+        s3c_rtc_setaie(&dev->dev, 0);
 
         clk_disable(rtc_clk);
         clk_put(rtc_clk);