lc823450_rtc: use small lock in arch/arm/src/lc823450/lc823450_rtc.c

reason:
We would like to replace the big lock with a small lock.

Signed-off-by: hujun5 <[email protected]>

Author: hujun260

arch/arm/src/lc823450/lc823450_rtc.c

@@ -28,6 +28,7 @@
 
 #include <nuttx/arch.h>
 #include <nuttx/irq.h>
+#include <nuttx/spinlock.h>
 #include <nuttx/timers/rtc.h>
 
 #ifdef CONFIG_RTC_ALARM
@@ -136,6 +137,7 @@ static void rtc_pmnotify(struct pm_callback_s *cb, enum pm_state_e pmstate);
 
 #ifdef CONFIG_RTC_ALARM
 static alarmcb_t g_alarmcb;
+static spinlock_t g_alarmcb_lock = SP_UNLOCKED;
 #endif
 
 #ifdef CONFIG_RTC_SAVE_DEFAULT
@@ -581,6 +583,7 @@ int up_rtc_settime(const struct timespec *ts)
 #ifdef CONFIG_RTC_ALARM
 int up_rtc_setalarm(const struct timespec *ts, alarmcb_t callback)
 {
+  irqstate_t   flags;
   struct tm *tp;
 
   if (g_alarmcb)
@@ -589,9 +592,12 @@ int up_rtc_setalarm(const struct timespec *ts, alarmcb_t callback)
     }
 
   tp = gmtime(&ts->tv_sec);
+
 #ifdef CONFIG_RTC_DIV
   tm_divider(tp, CONFIG_RTC_DIV_M, CONFIG_RTC_DIV_N);
 #endif /* CONFIG_RTC_DIV */
+
+  flags = spin_lock_irqsave(&g_alarmcb_lock);
   g_alarmcb = callback;
 #if 0
   llinfo("SETALARM (%04d/%02d/%02d %02d:%02d:%02d)\n",
@@ -623,6 +629,8 @@ int up_rtc_setalarm(const struct timespec *ts, alarmcb_t callback)
 
   modifyreg8(RTC_RTCINT, 1 << RTC_RTCINT_SET, 1 << RTC_RTCINT_AIE);
 
+  spin_unlock_irqrestore(&g_alarmcb_lock, flags);
+
   return OK;
 }
 
@@ -633,14 +641,14 @@ int up_rtc_setalarm(const struct timespec *ts, alarmcb_t callback)
 int up_rtc_cancelalarm(void)
 {
   irqstate_t   flags;
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_alarmcb_lock);
   g_alarmcb = NULL;
 
   /* Disable IRQ */
 
   putreg8(0, RTC_RTCINT);
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_alarmcb_lock, flags);
   return 0;
 }