STM32 RTC Alarm: Add Neil's alarm cancellation logic

arch/arm/src/stm32/stm32_rtc_lowerhalf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/stm32/stm32_rtc_lowerhalf.c
  *
- *   Copyright (C) 2015 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2015-2016 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -33,6 +33,8 @@
  *
  ****************************************************************************/
 
+/* REVISIT:  This driver is *not* thread-safe! */
+
 /****************************************************************************
  * Included Files
  ****************************************************************************/
@@ -490,9 +492,11 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
 
           seconds = mktime(&time);
 
-          /* Add the seconds offset */
+          /* Add the seconds offset.  Add one to the number of seconds
+           * because we are unsure of the phase of the timer.
+           */
 
-          seconds += alarminfo->reltime;
+          seconds += (alarminfo->reltime + 1);
 
           /* And convert the time back to broken out format */
 
@@ -563,9 +567,11 @@ static int stm32_setrelative(FAR struct rtc_lowerhalf_s *lower,
       ts.tv_nsec = 0;
 #endif
 
-      /* Add the seconds offset */
+      /* Add the seconds offset.  Add one to the number of seconds because
+       * we are unsure of the phase of the timer.
+       */
 
-      ts.tv_sec += alarminfo->reltime;
+      ts.tv_sec   += (alarminfo->reltime + 1);
 
       /* Remember the callback information */
 

arch/arm/src/stm32/stm32f40xxx_rtcc.c

@@ -787,7 +787,7 @@ static int rtchw_set_alrmar(rtc_alarmreg_t alarmreg)
   ret = rtchw_check_alrawf();
   if (ret != OK)
     {
-      goto rtchw_set_alrmar_exit;
+      goto errout_with_wprunlock;
     }
 
   /* Set the RTC Alarm register */
@@ -802,7 +802,7 @@ static int rtchw_set_alrmar(rtc_alarmreg_t alarmreg)
   cr |= (RTC_CR_ALRAE | RTC_CR_ALRAIE);
   putreg32(cr, STM32_RTC_CR);
 
-rtchw_set_alrmar_exit:
+errout_with_wprunlock:
   rtc_wprlock();
   return ret;
 }
@@ -1406,4 +1406,124 @@ int stm32_rtc_setalarm(FAR struct alm_setalarm_s *alminfo)
 }
 #endif
 
+/****************************************************************************
+ * Name: stm32_rtc_cancelalarm
+ *
+ * Description:
+ *   Cancel an alaram.
+ *
+ * Input Parameters:
+ *  alarmid - Identifies the alarm to be cancelled
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_RTC_ALARM
+int stm32_rtc_cancelalarm(enum alm_id_e alarmid)
+{
+  int ret = -EINVAL;
+
+  DEBUGASSERT(RTC_ALARM_LAST > alarmid);
+
+  /* Cancel the alarm in hardware and disable interrupts */
+
+  switch (alarmid)
+    {
+      case RTC_ALARMA:
+        {
+          /* Cancel the global callback function */
+
+           g_alarmcb[alarmid].ac_cb  = NULL;
+           g_alarmcb[alarmid].ac_arg = NULL;
+
+          /* Need to follow RTC register wrote protection.
+           * Disable the write protection for RTC registers
+           */
+
+          rtc_wprunlock();
+
+#if 0
+          /* Set Initialization mode */
+
+          ret = rtc_enterinit();
+          if (ret < 0)
+            {
+              goto errout_with_wprunlock;
+            }
+#endif
+
+          /* Disable RTC alarm and interrupt */
+
+          modifyreg32(STM32_RTC_CR, (RTC_CR_ALRAE | RTC_CR_ALRAIE), 0);
+
+          ret = rtchw_check_alrawf();
+          if (ret < 0)
+            {
+              goto errout_with_wprunlock;
+            }
+
+          /* Unset the alarm */
+
+          putreg32(-1, STM32_RTC_ALRMAR);
+          rtc_wprlock();
+          ret = OK;
+        }
+        break;
+
+      case RTC_ALARMB:
+        {
+          /* Cancel the global callback function */
+
+           g_alarmcb[alarmid].ac_cb  = NULL;
+           g_alarmcb[alarmid].ac_arg = NULL;
+
+          /* Need to follow RTC register wrote protection.
+           * Disable the write protection for RTC registers
+           */
+
+          rtc_wprunlock();
+
+#if 0
+          /* Set Initialization mode */
+
+          ret = rtc_enterinit();
+          if (ret < 0)
+            {
+              goto errout_with_wprunlock;
+            }
+#endif
+
+          /* Disable RTC alarm and interrupt */
+
+          modifyreg32(STM32_RTC_CR, (RTC_CR_ALRBE | RTC_CR_ALRBIE), 0);
+
+          ret = rtchw_check_alrbwf();
+          if (ret < 0)
+            {
+              goto errout_with_wprunlock;
+            }
+
+          /* Unset the alarm */
+
+          putreg32(-1, STM32_RTC_ALRMBR);
+          rtc_wprlock();
+          ret = OK;
+        }
+        break;
+
+      default:
+        rtcvdbg("ERROR: Invalid ALARM%d\n", alminfo->as_id);
+        break;
+    }
+
+  return ret;
+
+errout_with_wprunlock:
+  rtc_wprlock();
+  return ret;
+}
+#endif
+
 #endif /* CONFIG_RTC */

arch/arm/src/stm32l4/stm32l4_rtc_lowerhalf.c

@@ -34,6 +34,8 @@
  *
  ****************************************************************************/
 
+/* REVISIT:  This driver is *not* thread-safe! */
+
 /****************************************************************************
  * Included Files
  ****************************************************************************/