RTC: Extend interface by adding a method to set the alarm relative to the current time

arch

@@ -1 +1 @@
-Subproject commit 4a18471087626499f2f57a07238a32cfe803e6d0
+Subproject commit 68a1918ab42332510feca0a2203b768c7bb0c792

drivers/timers/rtc.c

@@ -365,7 +365,7 @@ static int rtc_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
 
         DEBUGASSERT(alarminfo != NULL);
         alarmid = alarminfo->id;
-        DEBUGASSERT(alarminfo->id >= 0 && alarminfo->id < RTC_NALARMS);
+        DEBUGASSERT(alarmid >= 0 && alarmid < RTC_NALARMS);
 
         /* Is the alarm active? */
 
@@ -411,6 +411,69 @@ static int rtc_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
       }
       break;
 
+    /* RTC_SET_RELATIVE sets the alarm time relative to the current time.
+     *
+     * Argument: A read-only reference to a struct rtc_setrelative_s containing the
+     *           new relative alarm time to be set.
+     */
+
+
+    case RTC_SET_RELATIVE:
+      {
+        FAR const struct rtc_setrelative_s *alarminfo =
+          (FAR const struct rtc_setrelative_s *)((uintptr_t)arg);
+        FAR struct rtc_alarminfo_s *upperinfo;
+        struct lower_setrelative_s lowerinfo;
+        int alarmid;
+
+        DEBUGASSERT(alarminfo != NULL);
+        alarmid = alarminfo->id;
+        DEBUGASSERT(alarmid >= 0 && alarmid < RTC_NALARMS);
+
+        /* Is the alarm active? */
+
+        upperinfo = &upper->alarminfo[alarmid];
+        if (upperinfo->active)
+          {
+            /* Yes, cancel the alarm */
+
+            if (ops->cancelalarm)
+              {
+                (void)ops->cancelalarm(upper->lower, alarmid);
+              }
+
+            upperinfo->active = false;
+          }
+
+        if (ops->setrelative)
+          {
+            /* Save the signal info to be used to notify the caller when the
+             * alarm expires.
+             */
+
+            upperinfo->active   = true;
+            upperinfo->signo    = alarminfo->signo;
+            upperinfo->pid      = alarminfo->pid;
+            upperinfo->sigvalue = alarminfo->sigvalue;
+
+            /* Format the alarm info needed by the lower half driver */
+
+            lowerinfo.id        = alarmid;
+            lowerinfo.cb        = rtc_alarm_callback;
+            lowerinfo.priv      = (FAR void *)upper;
+            lowerinfo.reltime   = alarminfo->reltime;
+
+            /* Then set the alarm */
+
+            ret = ops->setrelative(upper->lower, &lowerinfo);
+            if (ret < 0)
+              {
+                upperinfo->active = false;
+              }
+          }
+      }
+      break;
+
     /* RTC_WKALRM_CANCEL cancel the alarm.
      *
      * Argument: An ALARM ID value that indicates which alarm should be

include/nuttx/timers/rtc.h

@@ -151,12 +151,20 @@
 
 #define RTC_SET_ALARM      _RTCIOC(0x0003)
 
-/* RTC_WKALRM_CANCEL cancel the alarm.
+/* RTC_SET_RELATIVE sets the alarm time relative to the current time.
+ *
+ * Argument: A read-only reference to a struct rtc_setrelative_s containing the
+ *           new relative alarm time to be set.
+ */
+
+#define RTC_SET_RELATIVE   _RTCIOC(0x0004)
+
+/* RTC_SET_RELATIVE cancel the alarm.
  *
  * Argument: An ALARM ID value that indicates which alarm should be canceled.
  */
 
-#define RTC_CANCEL_ALARM   _RTCIOC(0x004)
+#define RTC_CANCEL_ALARM   _RTCIOC(0x0005)
 
 /* Architecture-specific RTC IOCTLS should begin at RTC_USER_IOCBASE.  For
  * example:
@@ -166,7 +174,7 @@
  *   etc.
  */
 
-#define RTC_USER_IOCBASE   0x0005
+#define RTC_USER_IOCBASE   0x0006
 
 /****************************************************************************
  * Public Types
@@ -207,7 +215,7 @@ struct rtc_rdalarm_s
   struct rtc_time time;     /* Current RTC time (if enabled) */
 };
 
-/* Structure used with the RTC_SETALARM IOCTL command. */
+/* Structure used with the RTC_SET_ALARM IOCTL command. */
 
 struct rtc_setalarm_s
 {
@@ -218,6 +226,17 @@ struct rtc_setalarm_s
   struct rtc_time time;     /* Alarm time */
 };
 
+/* Structure used with the RTC_SET_RELATIVE IOCTL command. */
+
+struct rtc_setrelative_s
+{
+  uint8_t id;               /* Indicates the alarm to be set */
+  uint8_t signo;            /* Signal number for alarm notification */
+  pid_t pid;                /* Identifies task to be notified */
+  union sigval sigvalue;    /* Data passed with notification */
+  time_t reltime;           /* Relative time in seconds */
+};
+
 /* Callback type used by the RTC harware to notify the RTC driver when the
  * alarm expires.
  */
@@ -233,6 +252,16 @@ struct lower_setalarm_s
   FAR void *priv;           /* Private argurment to accompany callback */
   struct rtc_time time;     /* Alarm time */
 };
+
+/* Structure used with the setrelative method */
+
+struct lower_setrelative_s
+{
+  uint8_t id;               /* Indicates the alarm to be set */
+  rtc_alarm_callback_t cb;  /* Callback when the alarm expires */
+  FAR void *priv;           /* Private argurment to accompany callback */
+  time_t reltime;           /* Relative time in seconds */
+};
 #endif
 
 /* The RTC driver is implemented as a common, upper-half character driver
@@ -266,6 +295,11 @@ struct rtc_ops_s
   CODE int (*setalarm)(FAR struct rtc_lowerhalf_s *lower,
                        FAR const struct lower_setalarm_s *alarminfo);
 
+  /* setalarm sets up a new alarm relative to the current time. */
+
+  CODE int (*setrelative)(FAR struct rtc_lowerhalf_s *lower,
+                          FAR const struct lower_setrelative_s *alarminfo);
+
   /* cancelalarm cancels the current alarm. */
 
   CODE int (*cancelalarm)(FAR struct rtc_lowerhalf_s *lower, int alarmid);