rtc: s3c: Rewrite clock handling

s3c_rtc_enable/disable_clk() functions were designed to be called multiple
times without reference counting, because they were initially only used in
alarm setting/clearing functions, which can be called both when alarm is
already set or not. Later however, calls to those functions have been added to
other places in the driver - like time and /proc reading callbacks, what
results in broken alarm if any of such events happens after the alarm has
been set. Fix this by simplifying s3c_rtc_enable/disable_clk() functions
to rely on proper reference counting in clock core and move alarm enable
counter to s3c_rtc_setaie() function.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 31 insertions, 43 deletions

diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
index 04c68178c42d..ea82efba6f94 100644
--- a/drivers/rtc/rtc-s3c.c
+++ b/drivers/rtc/rtc-s3c.c
@@ -39,7 +39,7 @@ struct s3c_rtc {
         void __iomem *base;
         struct clk *rtc_clk;
         struct clk *rtc_src_clk;
-        bool clk_disabled;
+        bool alarm_enabled;
 
         const struct s3c_rtc_data *data;
 
@@ -47,7 +47,7 @@ struct s3c_rtc {
         int irq_tick;
 
         spinlock_t pie_lock;
-        spinlock_t alarm_clk_lock;
+        spinlock_t alarm_lock;
 
         int ticnt_save;
         int ticnt_en_save;
@@ -70,44 +70,27 @@ struct s3c_rtc_data {
 
 static int s3c_rtc_enable_clk(struct s3c_rtc *info)
 {
-        unsigned long irq_flags;
-        int ret = 0;
+        int ret;
 
-        spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
+        ret = clk_enable(info->rtc_clk);
+        if (ret)
+                return ret;
 
-        if (info->clk_disabled) {
-                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;
-                        }
+        if (info->data->needs_src_clk) {
+                ret = clk_enable(info->rtc_src_clk);
+                if (ret) {
+                        clk_disable(info->rtc_clk);
+                        return ret;
                 }
-                info->clk_disabled = false;
         }
-
-out:
-        spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
-
-        return ret;
+        return 0;
 }
 
 static void s3c_rtc_disable_clk(struct s3c_rtc *info)
 {
-        unsigned long irq_flags;
-
-        spin_lock_irqsave(&info->alarm_clk_lock, irq_flags);
-        if (!info->clk_disabled) {
-                if (info->data->needs_src_clk)
-                        clk_disable(info->rtc_src_clk);
-                clk_disable(info->rtc_clk);
-                info->clk_disabled = true;
-        }
-        spin_unlock_irqrestore(&info->alarm_clk_lock, irq_flags);
+        if (info->data->needs_src_clk)
+                clk_disable(info->rtc_src_clk);
+        clk_disable(info->rtc_clk);
 }
 
 /* IRQ Handlers */
@@ -135,6 +118,7 @@ static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
 static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 {
         struct s3c_rtc *info = dev_get_drvdata(dev);
+        unsigned long flags;
         unsigned int tmp;
         int ret;
 
@@ -151,17 +135,19 @@ static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
 
         writeb(tmp, info->base + S3C2410_RTCALM);
 
-        s3c_rtc_disable_clk(info);
+        spin_lock_irqsave(&info->alarm_lock, flags);
 
-        if (enabled) {
-                ret = s3c_rtc_enable_clk(info);
-                if (ret)
-                        return ret;
-        } else {
+        if (info->alarm_enabled && !enabled)
                 s3c_rtc_disable_clk(info);
-        }
+        else if (!info->alarm_enabled && enabled)
+                ret = s3c_rtc_enable_clk(info);
 
-        return 0;
+        info->alarm_enabled = enabled;
+        spin_unlock_irqrestore(&info->alarm_lock, flags);
+
+        s3c_rtc_disable_clk(info);
+
+        return ret;
 }
 
 /* Set RTC frequency */
@@ -357,10 +343,10 @@ static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
         writeb(alrm_en, info->base + S3C2410_RTCALM);
 
-        s3c_rtc_disable_clk(info);
-
         s3c_rtc_setaie(dev, alrm->enabled);
 
+        s3c_rtc_disable_clk(info);
+
         return 0;
 }
 
@@ -491,7 +477,7 @@ static int s3c_rtc_probe(struct platform_device *pdev)
                 return -EINVAL;
         }
         spin_lock_init(&info->pie_lock);
-        spin_lock_init(&info->alarm_clk_lock);
+        spin_lock_init(&info->alarm_lock);
 
         platform_set_drvdata(pdev, info);
 
@@ -591,6 +577,8 @@ static int s3c_rtc_probe(struct platform_device *pdev)
 
         s3c_rtc_setfreq(info, 1);
 
+        s3c_rtc_disable_clk(info);
+
         return 0;
 
 err_nortc: