5 files changed, 67 insertions, 24 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 9a2bd4947007..3ee17c4d7298 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -793,9 +793,13 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
 	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
 	struct rtc_time tm;
 	ktime_t now;
+	int err;
+
+	err = __rtc_read_time(rtc, &tm);
+	if (err)
+		return err;
 
 	timer->enabled = 1;
-	__rtc_read_time(rtc, &tm);
 	now = rtc_tm_to_ktime(tm);
 
 	/* Skip over expired timers */
@@ -809,7 +813,6 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
 	trace_rtc_timer_enqueue(timer);
 	if (!next || ktime_before(timer->node.expires, next->expires)) {
 		struct rtc_wkalrm alarm;
-		int err;
 
 		alarm.time = rtc_ktime_to_tm(timer->node.expires);
 		alarm.enabled = 1;
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index dc3f8b0dde98..b90a603d6b12 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -222,6 +222,8 @@ static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
 
 static int cmos_read_time(struct device *dev, struct rtc_time *t)
 {
+	int ret;
+
 	/*
 	 * If pm_trace abused the RTC for storage, set the timespec to 0,
 	 * which tells the caller that this RTC value is unusable.
@@ -229,7 +231,12 @@ static int cmos_read_time(struct device *dev, struct rtc_time *t)
 	if (!pm_trace_rtc_valid())
 		return -EIO;
 
-	mc146818_get_time(t);
+	ret = mc146818_get_time(t);
+	if (ret < 0) {
+		dev_err_ratelimited(dev, "unable to read current time\n");
+		return ret;
+	}
+
 	return 0;
 }
 
@@ -793,16 +800,14 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
 
 	rename_region(ports, dev_name(&cmos_rtc.rtc->dev));
 
-	spin_lock_irq(&rtc_lock);
-
-	/* Ensure that the RTC is accessible. Bit 6 must be 0! */
-	if ((CMOS_READ(RTC_VALID) & 0x40) != 0) {
-		spin_unlock_irq(&rtc_lock);
-		dev_warn(dev, "not accessible\n");
+	if (!mc146818_does_rtc_work()) {
+		dev_warn(dev, "broken or not accessible\n");
 		retval = -ENXIO;
 		goto cleanup1;
 	}
 
+	spin_lock_irq(&rtc_lock);
+
 	if (!(flags & CMOS_RTC_FLAGS_NOFREQ)) {
 		/* force periodic irq to CMOS reset default of 1024Hz;
 		 *
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c
index 2065842f775d..8abac672f3cb 100644
--- a/drivers/rtc/rtc-mc146818-lib.c
+++ b/drivers/rtc/rtc-mc146818-lib.c
@@ -8,10 +8,36 @@
 #include <linux/acpi.h>
 #endif
 
-unsigned int mc146818_get_time(struct rtc_time *time)
+/*
+ * If the UIP (Update-in-progress) bit of the RTC is set for more then
+ * 10ms, the RTC is apparently broken or not present.
+ */
+bool mc146818_does_rtc_work(void)
+{
+	int i;
+	unsigned char val;
+	unsigned long flags;
+
+	for (i = 0; i < 10; i++) {
+		spin_lock_irqsave(&rtc_lock, flags);
+		val = CMOS_READ(RTC_FREQ_SELECT);
+		spin_unlock_irqrestore(&rtc_lock, flags);
+
+		if ((val & RTC_UIP) == 0)
+			return true;
+
+		mdelay(1);
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(mc146818_does_rtc_work);
+
+int mc146818_get_time(struct rtc_time *time)
 {
 	unsigned char ctrl;
 	unsigned long flags;
+	unsigned int iter_count = 0;
 	unsigned char century = 0;
 	bool retry;
 
@@ -20,13 +46,13 @@ unsigned int mc146818_get_time(struct rtc_time *time)
 #endif
 
 again:
-	spin_lock_irqsave(&rtc_lock, flags);
-	/* Ensure that the RTC is accessible. Bit 6 must be 0! */
-	if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x40) != 0)) {
-		spin_unlock_irqrestore(&rtc_lock, flags);
-		memset(time, 0xff, sizeof(*time));
-		return 0;
+	if (iter_count > 10) {
+		memset(time, 0, sizeof(*time));
+		return -EIO;
 	}
+	iter_count++;
+
+	spin_lock_irqsave(&rtc_lock, flags);
 
 	/*
 	 * Check whether there is an update in progress during which the
@@ -116,7 +142,7 @@ again:
 
 	time->tm_mon--;
 
-	return RTC_24H;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(mc146818_get_time);
 
@@ -176,8 +202,10 @@ int mc146818_set_time(struct rtc_time *time)
 	if (yrs >= 100)
 		yrs -= 100;
 
-	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
-	    || RTC_ALWAYS_BCD) {
+	spin_lock_irqsave(&rtc_lock, flags);
+	save_control = CMOS_READ(RTC_CONTROL);
+	spin_unlock_irqrestore(&rtc_lock, flags);
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 		sec = bin2bcd(sec);
 		min = bin2bcd(min);
 		hrs = bin2bcd(hrs);
diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c
index e38ee8848385..bad6a5d9c683 100644
--- a/drivers/rtc/rtc-pl031.c
+++ b/drivers/rtc/rtc-pl031.c
@@ -350,9 +350,6 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 		}
 	}
 
-	if (!adev->irq[0])
-		clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
-
 	device_init_wakeup(&adev->dev, true);
 	ldata->rtc = devm_rtc_allocate_device(&adev->dev);
 	if (IS_ERR(ldata->rtc)) {
@@ -360,6 +357,9 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
 		goto out;
 	}
 
+	if (!adev->irq[0])
+		clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
+
 	ldata->rtc->ops = ops;
 	ldata->rtc->range_min = vendor->range_min;
 	ldata->rtc->range_max = vendor->range_max;
diff --git a/drivers/rtc/rtc-wm8350.c b/drivers/rtc/rtc-wm8350.c
index 2018614f258f..6eaa9321c074 100644
--- a/drivers/rtc/rtc-wm8350.c
+++ b/drivers/rtc/rtc-wm8350.c
@@ -432,14 +432,21 @@ static int wm8350_rtc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
+	ret = wm8350_register_irq(wm8350, WM8350_IRQ_RTC_SEC,
 			    wm8350_rtc_update_handler, 0,
 			    "RTC Seconds", wm8350);
+	if (ret)
+		return ret;
+
 	wm8350_mask_irq(wm8350, WM8350_IRQ_RTC_SEC);
 
-	wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
+	ret = wm8350_register_irq(wm8350, WM8350_IRQ_RTC_ALM,
 			    wm8350_rtc_alarm_handler, 0,
 			    "RTC Alarm", wm8350);
+	if (ret) {
+		wm8350_free_irq(wm8350, WM8350_IRQ_RTC_SEC, wm8350);
+		return ret;
+	}
 
 	return 0;
 }