rtc: s3c: Handle clock enable failures

clk_enable() can fail so handle such case.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-s3c.c

@@ -68,18 +68,32 @@ struct s3c_rtc_data {
 	void (*disable) (struct s3c_rtc *info);
 };
 
-static void s3c_rtc_enable_clk(struct s3c_rtc *info)
+static int s3c_rtc_enable_clk(struct s3c_rtc *info)
 {
 	unsigned long irq_flags;
+	int ret = 0;
 
 	spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
+
 	if (info->clk_disabled) {
-		clk_enable(info->rtc_clk);
-		if (info->data->needs_src_clk)
-			clk_enable(info->rtc_src_clk);
+		ret = clk_enable(info->rtc_clk);
+		if (ret)
+			goto out;
+
+		if (info->data->needs_src_clk) {
+			ret = clk_enable(info->rtc_src_clk);
+			if (ret) {
+				clk_disable(info->rtc_clk);
+				goto out;
+			}
+		}
 		info->clk_disabled = false;
 	}
+
+out:
 	spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
+
+	return ret;
 }
 
 static void s3c_rtc_disable_clk(struct s3c_rtc *info)
@@ -122,10 +136,13 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 {
 	struct s3c_rtc *info = dev_get_drvdata(dev);
 	unsigned int tmp;
+	int ret;
 
 	dev_dbg(info->dev, "%s: aie=%d\n", __func__, enabled);
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	tmp = readb(info->base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;
 
@@ -136,10 +153,13 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 
 	s3c_rtc_disable_clk(info);
 
-	if (enabled)
-		s3c_rtc_enable_clk(info);
-	else
+	if (enabled) {
+		ret = s3c_rtc_enable_clk(info);
+		if (ret)
+			return ret;
+	} else {
 		s3c_rtc_disable_clk(info);
+	}
 
 	return 0;
 }
@@ -147,10 +167,14 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 /* Set RTC frequency */
 static int s3c_rtc_setfreq(struct s3c_rtc *info, int freq)
 {
+	int ret;
+
 	if (!is_power_of_2(freq))
 		return -EINVAL;
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 	spin_lock_irq(&info->pie_lock);
 
 	if (info->data->set_freq)
@@ -167,8 +191,11 @@ static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
 {
 	struct s3c_rtc *info = dev_get_drvdata(dev);
 	unsigned int have_retried = 0;
+	int ret;
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 retry_get_time:
 	rtc_tm->tm_min  = readb(info->base + S3C2410_RTCMIN);
@@ -212,6 +239,7 @@ static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
 {
 	struct s3c_rtc *info = dev_get_drvdata(dev);
 	int year = tm->tm_year - 100;
+	int ret;
 
 	dev_dbg(dev, "set time %04d.%02d.%02d %02d:%02d:%02d\n",
 		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
@@ -224,7 +252,9 @@ static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
 		return -EINVAL;
 	}
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	writeb(bin2bcd(tm->tm_sec),  info->base + S3C2410_RTCSEC);
 	writeb(bin2bcd(tm->tm_min),  info->base + S3C2410_RTCMIN);
@@ -243,8 +273,11 @@ static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	struct s3c_rtc *info = dev_get_drvdata(dev);
 	struct rtc_time *alm_tm = &alrm->time;
 	unsigned int alm_en;
+	int ret;
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	alm_tm->tm_sec  = readb(info->base + S3C2410_ALMSEC);
 	alm_tm->tm_min  = readb(info->base + S3C2410_ALMMIN);
@@ -293,6 +326,7 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	struct s3c_rtc *info = dev_get_drvdata(dev);
 	struct rtc_time *tm = &alrm->time;
 	unsigned int alrm_en;
+	int ret;
 	int year = tm->tm_year - 100;
 
 	dev_dbg(dev, "s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
@@ -300,7 +334,9 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 		1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
 		tm->tm_hour, tm->tm_min, tm->tm_sec);
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	alrm_en = readb(info->base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;
 	writeb(0x00, info->base + S3C2410_RTCALM);
@@ -349,8 +385,11 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
 {
 	struct s3c_rtc *info = dev_get_drvdata(dev);
+	int ret;
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	if (info->data->enable_tick)
 		info->data->enable_tick(info, seq);
@@ -589,8 +628,11 @@ static int s3c_rtc_probe(struct platform_device *pdev)
 static int s3c_rtc_suspend(struct device *dev)
 {
 	struct s3c_rtc *info = dev_get_drvdata(dev);
+	int ret;
 
-	s3c_rtc_enable_clk(info);
+	ret = s3c_rtc_enable_clk(info);
+	if (ret)
+		return ret;
 
 	/* save TICNT for anyone using periodic interrupts */
 	if (info->data->save_tick_cnt)