From a6c68d233d76b5ba21e4bad1625edf9eb3572b29 Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Fri, 24 Aug 2018 10:16:17 -0600
Subject: [PATCH] drivers/timers:  Add maxtimeout method to the struct
 timer_ops_s interface

---
 drivers/timers/timer.c       | 20 ++++++++++++++++++++
 include/nuttx/timers/timer.h |  8 ++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/timers/timer.c b/drivers/timers/timer.c
index 6bb4edeb19..5c828873df 100644
--- a/drivers/timers/timer.c
+++ b/drivers/timers/timer.c
@@ -390,6 +390,26 @@ static int timer_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
       }
       break;
 
+    /* cmd:         TCIOC_MAXTIMEOUT
+     * Description: Get the maximum supported timeout value
+     * Argument:    A 32-bit timeout value in microseconds.
+     */
+
+    case TCIOC_MAXTIMEOUT:
+      {
+        /*  Get the maximum supported timeout value */
+
+        if (lower->ops->maxtimeout) /* Optional */
+          {
+            ret = lower->ops->maxtimeout(lower, (uint32_t *)arg);
+          }
+        else
+          {
+            ret = -ENOSYS;
+          }
+      }
+      break;
+
     /* Any unrecognized IOCTL commands might be platform-specific ioctl commands */
 
     default:
diff --git a/include/nuttx/timers/timer.h b/include/nuttx/timers/timer.h
index db59e81819..420e8dfbb2 100644
--- a/include/nuttx/timers/timer.h
+++ b/include/nuttx/timers/timer.h
@@ -74,6 +74,8 @@
  *                      the timer expires.
  *                      Argument: A read-only pointer to an instance of
  *                      stuct timer_notify_s.
+ * TCIOC_MAXTIMEOUT   - Get the maximum supported timeout value
+ *                      Argument: A 32-bit timeout value in microseconds.
  *
  * WARNING: May change TCIOC_SETTIMEOUT to pass pointer to 64bit nanoseconds
  * or timespec structure.
@@ -93,6 +95,7 @@
 #define TCIOC_GETSTATUS    _TCIOC(0x0003)
 #define TCIOC_SETTIMEOUT   _TCIOC(0x0004)
 #define TCIOC_NOTIFICATION _TCIOC(0x0005)
+#define TCIOC_MAXTIMEOUT   _TCIOC(0x0006)
 
 /* Bit Settings *************************************************************/
 /* Bit settings for the struct timer_status_s flags field */
@@ -172,6 +175,11 @@ struct timer_ops_s
 
   CODE int (*ioctl)(FAR struct timer_lowerhalf_s *lower, int cmd,
                     unsigned long arg);
+
+  /* Get the maximum supported timeout value */
+
+  CODE int (*maxtimeout)(FAR struct timer_lowerhalf_s *lower,
+                         FAR uint32_t *maxtimeout);
 };
 
 /* This structure provides the publicly visible representation of the