From dc366ecf7a2946c8f071735f5f2065d51000240a Mon Sep 17 00:00:00 2001
From: Grissiom <chaos.proton@gmail.com>
Date: Wed, 18 Jun 2014 11:16:21 +0800
Subject: [PATCH 1/2] device: only increase the ref_count when device is truly
 opened

---
 src/device.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/device.c b/src/device.c
index 75b88bf6e..7ee130041 100644
--- a/src/device.c
+++ b/src/device.c
@@ -239,11 +239,6 @@ rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflag)
         return -RT_EBUSY;
     }
 
-    dev->ref_count++;
-    /* don't let bad things happen silently. If you are bitten by this assert,
-     * please set the ref_count to a bigger type. */
-    RT_ASSERT(dev->ref_count != 0);
-
     /* call device open interface */
     if (dev->open != RT_NULL)
     {
@@ -252,8 +247,15 @@ rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflag)
 
     /* set open flag */
     if (result == RT_EOK || result == -RT_ENOSYS)
+    {
         dev->open_flag = oflag | RT_DEVICE_OFLAG_OPEN;
 
+        dev->ref_count++;
+        /* don't let bad things happen silently. If you are bitten by this assert,
+         * please set the ref_count to a bigger type. */
+        RT_ASSERT(dev->ref_count != 0);
+    }
+
     return result;
 }
 RTM_EXPORT(rt_device_open);

From aca8f8eb2d732af34be31b7c9dce43de5187496e Mon Sep 17 00:00:00 2001
From: Grissiom <chaos.proton@gmail.com>
Date: Wed, 18 Jun 2014 11:18:43 +0800
Subject: [PATCH 2/2] shell: print the ref count in `list_device`

---
 components/finsh/cmd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/components/finsh/cmd.c b/components/finsh/cmd.c
index 9a79ba396..e449e0c2d 100644
--- a/components/finsh/cmd.c
+++ b/components/finsh/cmd.c
@@ -471,17 +471,18 @@ static long _list_device(struct rt_list_node *list)
         "Unknown"
     };
 
-    rt_kprintf("device    type      \n");
-    rt_kprintf("-------- ---------- \n");
+    rt_kprintf("device   type                 ref count\n");
+    rt_kprintf("-------- -------------------- ----------\n");
     for (node = list->next; node != list; node = node->next)
     {
         device = (struct rt_device *)(rt_list_entry(node, struct rt_object, list));
-        rt_kprintf("%-8.*s %-8s \n",
+        rt_kprintf("%-8.*s %-20s %-8d\n",
                    RT_NAME_MAX,
                    device->parent.name,
                    (device->type <= RT_Device_Class_Unknown) ?
                    device_type_str[device->type] :
-                   device_type_str[RT_Device_Class_Unknown]);
+                   device_type_str[RT_Device_Class_Unknown],
+                   device->ref_count);
     }
 
     return 0;