drivers/timers: Add a new method to the struct oneshot_operations_s interface to get the current time from a oneshot timer driver (if it is available from the lower half)

drivers/timers/oneshot.c

@@ -46,7 +46,6 @@
 #include <semaphore.h>
 #include <signal.h>
 #include <assert.h>
-#include <errno.h>
 #include <debug.h>
 
 #include <nuttx/kmalloc.h>
@@ -306,6 +305,21 @@ static int oneshot_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
         }
         break;
 
+      /* OSIOC_CURRENT - Get the current time
+       *                 Argument: A reference to a struct timespec in
+       *                 which the current time will be returned.
+       */
+
+      case OSIOC_CURRENT:
+        {
+          FAR struct timespec *ts = (FAR struct timespec *)((uintptr_t)arg);
+
+          /* Get the current time */
+
+          ret = ONESHOT_CURRENT(priv->od_lower, ts);
+        }
+        break;
+
       default:
         {
           tmrerr("ERROR: Unrecognized cmd: %d arg: %ld\n", cmd, arg);

include/nuttx/timers/oneshot.h

@@ -42,6 +42,7 @@
 
 #include <nuttx/config.h>
 
+#include <errno.h>
 #include <stdint.h>
 #include <time.h>
 
@@ -68,6 +69,9 @@
  * OSIOC_CANCEL     - Stop the timer
  *                    Argument: A reference to a struct timespec in which
  *                    the time remaining will be returned.
+ * OSIOC_CURRENT    - Get the current time
+ *                    Argument: A reference to a struct timespec in which
+ *                    the current time will be returned.
  *
  * NOTE: _TCIOC(0x0020) througn _TCIOC(0x003f) are reserved for use by the
  * oneshot driver to assure that the values are unique.  Other timer drivers
@@ -77,6 +81,7 @@
 #define OSIOC_MAXDELAY   _TCIOC(0x0020)
 #define OSIOC_START      _TCIOC(0x0021)
 #define OSIOC_CANCEL     _TCIOC(0x0022)
+#define OSIOC_CURRENT    _TCIOC(0x0023)
 
 /* Method access helper macros **********************************************/
 
@@ -148,6 +153,27 @@
 
 #define ONESHOT_CANCEL(l,t) ((l)->ops->cancel(l,t))
 
+/****************************************************************************
+ * Name: ONESHOT_CURRENT
+ *
+ * Description:
+ *  Get the current time.
+ *
+ * Input Parameters:
+ *   lower   Caller allocated instance of the oneshot state structure.  This
+ *           structure must have been previously initialized via a call to
+ *           oneshot_initialize();
+ *   ts      The location in which to return the current time. A time of zero
+ *           is returned for the initialization moment.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success, a negated errno value is returned on
+ *   any failure.
+ *
+ ****************************************************************************/
+
+#define ONESHOT_CURRENT(l,t) ((l)->ops->current ? (l)->ops->current(l,t) : -ENOSYS)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -175,6 +201,8 @@ struct oneshot_operations_s
                     FAR const struct timespec *ts);
   CODE int (*cancel)(struct oneshot_lowerhalf_s *lower,
                      FAR struct timespec *ts);
+  CODE int (*current)(struct oneshot_lowerhalf_s *lower,
+                      FAR struct timespec *ts);
 };
 
 /* This structure describes the state of the oneshot timer lower-half driver */